Loading...
HomeMy WebLinkAbout2025-03-12 - Agenda Packet Historic Preservation Commission and Planning Commission Meeting Agenda Rancho Cucamonga Civic Center COUNCIL CHAMBERS March 12, 2025 10500 Civic Center Drive Rancho Cucamonga, CA 91730 7:00 PM A. CALL TO ORDER AND PLEDGE OF ALLEGIANCE ROLL CALL: Chairman Morales Vice Chairman Boling Commissioner Dopp Commissioner Daniels Commissioner Diaz B. PUBLIC COMMUNICATIONS This is the time and place for the general public to address the Planning/Historic Commission (“Planning Commission”) on any Consent Calendar item or any item not listed on the agenda that is within the Commission’s subject matter jurisdiction. The Planning Commission may not discuss any issue not included on the agenda, but may set the matter for discussion during a subsequent meeting. C. CONSENT CALENDAR C1. Consideration to adopt Regular Meeting Minutes of February 26th, 2025. D. PUBLIC HEARINGS D1. CERTIFICATE OF APPROPRIATENESS – ETIWANDA HISTORICAL SOCIETY – A request to rehabilitate the front porch of the Chaffey-Isle House, a historic landmark, by replacing the wood flooring with composite decking within the Very Low (VL) Residential Zone, located at 7086 Etiwanda Avenue; APN: 1089-071-26. This item is exempt from the requirements of the California Environmental Quality Act (CEQA) under State CEQA Guidelines Section 15301 – Existing Facilities and Section 15331 – Historical Resource Restoration/Rehabilitation (DRC2025-00040). E. GENERAL BUSINESS E1. Consideration to Receive and File the 2024 General Plan Annual Progress Report and the Housing Element Annual Progress Report. F. DIRECTOR ANNOUNCEMENTS G. COMMISSION ANNOUNCEMENTS H. ADJOURNMENT TO ADDRESS THE PLANNING COMMISSION The Planning Commission encourages free expression of all points of view. To allow all persons to speak, given the length of the agenda, please keep your remarks brief. If others have already expressed your position, you may simply indicate that you agree with a previous speaker. If appropriate, a spokesperson may present the views of your entire group. To encourage all views and promote courtesy to others, the audience should refrain from clapping, booing or shouts of approval or disagreement from the audience. If you need special assistance or accommodations to participate in this meeting, please contact the City Clerk's office at (909) 477-2700. Notification of 48 hours prior to the meeting will enable the City to make reasonable arrangements to ensure accessibility. Listening devices are available for the hearing impaired. The public may address the Planning Commission on any agenda item. To address the Planning Commission, please come forward to the podium. State your name for the record and speak into the microphone. After speaking, please complete a speaker card located next to the speaker’s podium. It is important to list your name, address (optional) and the agenda item letter your comments refer to. Comments are generally limited to 3 minutes per individual. If you wish to speak concerning an item not on the agenda, you may do so under “Public Communications.” As an alternative to participating in the meeting you may submit comments in writing to Elizabeth.Thornhill@cityofrc.us by 12:00 PM on the date of the meeting. Written comments will be distributed to the Commissioners and included in the record. AVAILABILITY OF STAFF REPORTS Copies of the staff reports or other documentation to each agenda item are available at www.CityofRC.us. APPEALS Any interested party who disagrees with the City Planning Commission decision may appeal the Commission’s decision to the City Council within 10 calendar days. Any appeals filed must be in writing with the City Clerk’s Office, state the reason for the appeal, and be accompanied by an appeal fee pursuant to the most adopted fee schedule for all decisions for the Commission. (Fees are established and governed by the City Council). Please turn off all cell phones while the meeting is in session. I, Elizabeth Thornhill, Executive Assistant of the City of Rancho Cucamonga, or my designee, hereby certify that a true, accurate copy of the foregoing agenda was posted Seventy-Two (72) hours prior to the meeting per Government Code 54954.2 at 10500 Civic Center Drive, Rancho Cucamonga, California and on the City's website. HPC/PC MINUTES – February 26, 2025 Page 1 of 5 2 8 3 1 Historic Preservation Commission and Planning Commission Agenda February 26, 2025 Draft Minutes Rancho Cucamonga, CA 91730 7:00 p.m. The regular joint meeting of the Historic Preservation Commission and Planning Commission was held on February 26, 2025. The meeting was called to order by Chairman Morales at 7:00 p.m. A. Roll Call Planning Commission present: Chairman Morales, Vice Chairman Boling, Commissioner Dopp, Commissioner Daniels and Commissioner Diaz. Staff Present: Katherine Reed, Assistant City Attorney; Jennifer Nakamura, Planning Director; Kirt Coury, Contract Planner; Mike Parmer, Engagement and Special Programs Director; Sean McPherson, Principal Planner; Elizabeth Thornhill, Executive Assistant. B. Public Communications Chairman Morales opened the public communications. Hearing no comments from the public, Chairman Morales closed the public communications. C. Consent Calendar C1. Consideration to adopt Regular Meeting Minutes of February 12, 2025. Motion: Moved by Vice Chairman Boling; seconded by Commissioner Daniels. Motion carried 5-0 approved the minutes as presented. D. Public Hearings D1. ENVIRONMENTAL ASSESSMENT, TENTATIVE PARCEL MAP, DESIGN REVIEW, CONDITIONAL USE PERMIT AND TREE REMOVAL PERMIT– LING YEN MOUNTAIN TEMPLE – A request to subdivide approximately 77.39 acres of land into 4 numbered lots including site plan and design review for the development of eight buildings for the operation of a Buddhist Temple for the purposes of worship, living quarters, and related administrative or support uses on certain property located near the northeast corner of DeCliff Drive and Ambleside Place. The Project site consists of portions of four parcels; APNs: 0226-061-47, 0226-061-73, 0226-061-74, and 0226-061-76. Primary Case File No. DRC2021-00187. Environmental review of the project has been conducted consistent with California Environmental Quality Act (CEQA) Guidelines Section 15183(a). Contract Planner Coury presented a PowerPoint presentation (copy on file). He stated there was an error in the Resolutions and Conditions with the omission of an existing parcel which should have    Page 3 HPC/PC MINUTES – February 26, 2025 Page 2 of 5 2 8 3 1 been referenced (APN: 0226-061-77). He clarified that the project will still result in 4 new parcels after the subdivision. Commissioner Dopp asked staff about the hillsides and fire risks, inquiring whether there have been discussions with the developer regarding fire mitigation strategies to ensure best practices in hillside communities. Contract Planner Coury responded that the applicant has been in discussions with the Fire Department and currently have plans under review. Commissioner Daniels asked staff what plans are anticipated for the area around EHNCP site. Contract Planner Coury answered that nothing has been talked about that he is aware of. Principal Planner McPherson mentioned that the majority of areas around the site are zoned for open space for flood control and no other applications or inquires have been received about the property. Vice Chairman Boling asked for clarity regarding the parking. He said the ample amount of parking that is provided in the multiple locations throughout the project area and the placement of the spaces were determined based upon anticipated peak usage for annual events, as opposed to regular and consistent daily use for those parking facilities. He said what we would expect much of the year is that the parking facility being proposed for development would be for excess capacity for festivals which occur infrequently and that is when the abundance of parking would be utilized. He wanted to make it clear to all in attendance and for the record to understand that this was over planned for daily use but appropriately sized for anticipated festival use which occur infrequently throughout the year. Contract Planner Coury confirmed. Principal Planner McPherson responded to Commissioner Daniels earlier question that there is one project application that has been received by staff for a five-unit residential development which is west to this site is zoned for residential development. He said any zone within the EHNCP that allows for residential development is highly rural in nature. Chairman Morales opened the public hearing. Applicant Chen was in attendance and available to answer questions. He indicated that they are in discussion with the Fire Department, and they have done extensive modifications to the landscape that does not easily burn. Commissioner Dopp asked if he knows the maximum amount of people that usually attend the big events at the existing temple facility. Applicant Chen responded approximately 200. Commissioner Dopp asked if the surrounding neighborhood has seen any significant impact from those number. Applicant Chen answered no and that the neighbors did not even know the temple existed.    Page 4 HPC/PC MINUTES – February 26, 2025 Page 3 of 5 2 8 3 1 Commissioner Dopp asked for the specific number of events we are looking at. Applicant Chen answered 12 events. He said there are three major events that have the maximum capacity of 500 people, and the other events would have 200 people. Commissioner Daniels asked what type of annual events they have. Applicant Chen indicated, but is not limited to, the following events: •Chinese New Year •Day for Repent •Retreats •Buddha and Vegetarian Festival •Blessing Service Commissioner Daniels asked if the facility is open to the public. Applicant Chen answered that there are one or two events that is somewhat private for the self- study session, but most of it is open to the public. Commissioner Daniels asked how many permanent people live there. Applicant Chen replied that there are 20-30 people, and they are on a rotation basis. Commissioner Diaz asked of the venue would be available for rental to people wishing to host celebrations there. Applicant Chen answered no. Wayne Smith, Resident, expressed concerns about using Ambleside Place as access to the temple, noting that it is a narrow road with traffic passing directly in front of his home. Applicant Chen mentioned the new portion of the street will be improved with curbs, cutter and sidewalk. Hearing no other comments, Chairman Morales closed the public hearing. Commissioner Dopp asked if the main entrance will be on the west or east side, where most people will be parking. Contract Planner Coury answered the main parking will be to the east side. Commissioner Dopp asked is it anticipated that the vast majority, if not all, traffic will go through Colonbero Road. Principal Planner McPherson answered both roads would be used as access. Commissioner Daniels stated he had a discussion with the Planning Director regarding fire sensors in the wildlife areas around the site. Planning Director Nakamura explained that they are working on a grant they received from the State to install wildfire sensors along corridors owned by LADWP. This will provide more active electronic monitoring in the foothill area to quickly detect fires, which is of major concern.    Page 5 HPC/PC MINUTES – February 26, 2025 Page 4 of 5 2 8 3 1 Commissioner Daniels expressed the way the complex is laid out is very functional. He said he likes the architecture and the landscape which will be an improvement to what is already there. Vice Chairman Boling stated there have been access concerns of the main entrance from the public and asked the applicant what their intended use is for primary access, if there is one anticipated. Applicant Chen answered that their preference is for people to come in from the east side but both accesses are open. Vice Chairman Boling reiterated the preference would be entrance to the east side. Applicant Chen confirmed. Vice Chairman Boling expressed he liked the building design and landscape proposal. He said the trees compliment the open space and natural habitat. He wants to make it clear that parking has been planned for based upon peak potential use that is anticipated for periodic festivals and there will be ample parking and will not be an issue. He appreciates the attention to the wildland interface aspects that have been coordinated with the Fire for on-site landscaping. He said the facility overall, the worship and learning, will support the existing and growing population of the City’s Buddha’s residence. Commissioner Dopp concurs with Boling and Daniels comments about the architecture and design. He appreciates Boling’s comments on the future of the site to try and defer parking and traffic through Colonbero which could likely handle it more efficiently. He said he still has trepidation of a project so close to the hills considering what has happened recently with the fires. He said while those concerns are relatively minor overall, the project is still a net positive for the community as evidenced by individuals in attendance tonight. Chairman Morales expressed his concerns of the fire risk because of the high winds. He appreciates the applicant working with the Fire Department. He said having a paved parking lot will be a big help and reduce the risk of fire. He likes the project, and mentioned that the parking issue has been addressed, encouraging people to use the east entrance. Motion: Moved by Vice Chairman Boling; seconded by Commissioner Daniels to adopt Resolution 2025-005, Tentative Parcel Map SUBTPM19720, Resolution 2025-006 Design Review DRC2021-00187, Resolution 2025-007 Conditional Use Permit DRC2021-00188, and Resolution 2025-008 Tree Removal Permit DRC2021-00189 with amendment to Resolutions and Conditions of Approval (APN: 0226-061-77). Motion carried 5-0. E. General Business E1. Finding of General Plan Conformity for Real Property Acquisition of Approximately 122 Acres Located East of West Cucamonga Truck Trail (Big Tree Road), generally north of Via Verde Street and Skyline Road Rancho Cucamonga area in unincorporated San Bernardino County; APNs: Portion of 0200-051-48 and 0200-051-49. Engagement and Special Programs Director Parmer presented a PowerPoint presentation (copy on file). Commissioner Diaz mentioned she read in the Staff Report that the land purchase is being funded with both State and Federal funds.    Page 6 HPC/PC MINUTES – February 26, 2025 Page 5 of 5 2 8 3 1 Engagement and Special Programs Director Parmer confirmed. Commissioner Diaz asked if we have the Federal funding available. Engagement and Special Programs Director Parmer confirmed. Commissioner Daniels asked if there are any plans for annexation of the property. Planning Director Nakamura answered no. Commissioner Diaz expressed that she is in support of this. Vice Chairman Boling stated for clarity that tonight’s action for the Commission to consider is limited to the assessment and determination of General Plan compatibility and conformance and not related to any specific project, activity, or land purchase. He expressed his appreciation to staff that in the Staff Report it called out and identified 16 points of the General Plan which helped support and give the Commissioners guidance necessary for them to render a decision that this is in conformance with the General Plan. Chairman Morales expressed that he is proud of the City for working with the different agencies to address the issues that have been there for a long time, especially for the residence that live there. Motion: Moved by Commissioner Diaz; seconded by Commissioner Daniels to adopt Resolution 2025-004, Proposed Acquisition of 122.09 Acres of Real Property Located East of West Cucamonga Truck Trail. Motion carried 5-0. F. Director Announcements - None G. Commission Announcements - None H. Adjournment Motion: Moved by Commissioner Diaz, seconded by Vice Chairman Boling to adjoin the meeting. Hearing no objections, Chairman Morales adjourned the meeting at 7:55 p.m. Respectfully submitted, Elizabeth Thornhill, Executive Assistant Planning Department Approved:    Page 7 DATE:March 12, 2025 TO:Chairman and Members of the Historic Preservation Commission FROM:Jennifer Nakamura, CNU-A, Planning Director INITIATED BY:Stacy Lee, Assistant Planner SUBJECT: CERTIFICATE OF APPROPRIATENESS – ETIWANDA HISTORICAL SOCIETY – A request to rehabilitate the front porch of the Chaffey-Isle House, a historic landmark, by replacing the wood flooring with composite decking within the Very Low (VL) Residential Zone, located at 7086 Etiwanda Avenue; APN: 1089-071-26. This item is exempt from the requirements of the California Environmental Quality Act (CEQA) under State CEQA Guidelines Section 15301 – Existing Facilities and Section 15331 – Historical Resource Restoration/Rehabilitation (DRC2025-00040). RECOMMENDATION: Staff recommends that the Historic Preservation Commission adopt a resolution for the approval of Certificate of Appropriateness DRC2025-00040 with the attached conditions of approval. BACKGROUND: The Chaffey-Isle House dates to the founding of the Etiwanda in the early 1880s by brothers George and William Chaffey. George was educated as an engineer, and William had a background in agriculture. They formed a partnership to develop an irrigated agricultural colony known at the time as Etiwanda Colony. After the Chaffey brothers relocated, the house passed through several owners before James C. Isle purchased a lot at the corner of Etiwanda Avenue and Highland Avenue in 1902. He moved the house, using log rollers, about half a mile to his newly purchased lot that is now the I-210 freeway by the 1970s. The property served as a rental dwelling and was eventually abandoned until it was acquired by San Bernardino Associated Governments (SANBAG) for the I-210 freeway construction. On May 9, 2001, the Historic Preservation Commission reviewed Historic Landmark Designation DRC2001-00119, a request to designate the structure as a local landmark and recommended approval to the City Council. On that same day, the Historic Preservation Commission approved Historic Landmark Alteration Permit DRC2001-00116 to allow rehabilitation of the Chaffey-Isle House and Conditional Use Permit DRC2001-00115 to establish a community building use. On June 6, 2001, the City Council approved Historic Landmark Designation DRC2001-00119 designating the Chaffey-Isle House as a historic landmark. At the request of the Etiwanda Historical Society, the City of Rancho Cucamonga acquired the structure and entered into a lease agreement with the Etiwanda Historical Society on November 6, 2013, moving the house to its current location at 7086 Etiwanda Avenue. The Chaffey-Isle House Lease between the City of Rancho Cucamonga and the Etiwanda Historical Society    Page 8 Page 2 of 6 2 7 4 2 requires the premises to be maintained and repaired at the Historical Society’s expense. It also prohibits the Historical Society from making any alterations without prior written consent from the City. Any changes must comply with applicable laws, including those related to accessibility. Pursuant to Development Code Section 17.18.040(B), “No person shall carry out or cause to be carried out any alteration, restoration, rehabilitation, construction, removal, relocation, or demolition of any historic landmark or contributing resource unless the city has first issued a certificate of appropriateness in accordance with the requirements of this chapter.” ANALYSIS: Site Characteristics The Chaffey-Isle House is a two-story, 1,768-square-foot structure located on a half-acre, relatively flat and rectangular parcel of land. The house itself was constructed around the 1880s and exhibits a “Second Empire” architectural theme. The period of significance for this style of architecture, which is a subset of Victorian, was roughly between 1860 and 1900, and most predominately between 1860 and 1880. Character defining features typical of Second Empire design include a steep, shingled mansard roof design with unelaborated dormers and windows. Porches, though not uncommon, are not found in most Second Empire construction on account that Second Empire houses have less eave overhang than other subsets of Victorian (i.e. Italianate). In this case, the porch of the Chaffey-Isle House wraps the east and south elevations, featuring turned wood columns supporting the mansard roof. The columns are slightly varied in diameter and height, with evidence of patching at their tops where fretwork may have been. The roof of the porch mirrors the main roof's pattern, with wood shingles in a hexagonal and diamond design. The porch floor consists of narrow tongue-and-groove boards with a center bead detail. Figure 1 – Front Elevation (East) Figure 2 – Side Elevation (South) The existing Land Use, General Plan, and Zoning for this project site and the surrounding properties are provided in the following table:    Page 9 Page 3 of 6 2 7 4 2 Land Use General Plan Zoning Site Historic Property Traditional Neighborhood Very Low (VL) Residential North Historic Property Traditional Neighborhood Very Low (VL) Residential West Single-Family Residence Traditional Neighborhood Very Low (VL) Residential South Community Trail General Open Space and Facilities Parks (P) East Historic Property Rural Open Space Very Low (VL) Residential Figure 3 – Site Map Project Overview As noted, the Chaffey-Isle House is currently in use as a museum and community building to promote the history of the Etiwanda area. The porch lacks appropriate sloping for drainage which has caused the wood planks to rot and the sun exposure from the south is fast deteriorating the wood planks. To continue using the structure in its existing capacity, rehabilitation of the front porch area with new decking material is necessary. The Etiwanda Historical Society is asking the Historic Preservation Commission to consider allowing replacement of the deck with an alternative material rather than wood planks. The lack of appropriate sloping for drainage as well as sun damage on the southern portion of the porch in addition to foot traffic related to the use will shorten the overall life span of the deck and require more frequent replacement than a more modern, but similar decking alternative. As a non-profit entity, the Etiwanda Historical Society is concerned about the long-term economic feasibility of replacing the deck at more frequent intervals by using “like for like” materials. The applicant is proposing to replace 620 square feet of the existing wood planks used for the flooring of the porch with “Trex Enhance” composite decking. This is a long-lasting decking material made from 95% recycled plastic film and reclaimed sawdust as an alternative to wood. As part of the rehabilitation, the applicant is also proposing to install a new subfloor joist and beam system due to severe water and termite damage. The proposed replacement of the deteriorated wood porch decking with composite decking will not result in a substantial adverse change to the historic resource. The composite material has N    Page 10 Page 4 of 6 2 7 4 2 been selected to closely match the original wood in appearance, texture, and color, ensuring the preservation of the porch’s historic character. Furthermore, the deterioration of the existing wood decking necessitates its replacement to maintain the structure’s integrity. As such, the project does not diminish the historical significance of the property of the broader historic region. The replacement composite decking will preserve the visual and structural character of the porch while enhancing durability and reducing the need for frequent repairs. Additionally, the project ensures the continued use and longevity of the historic resource, supporting the broader goals of historic preservation in the district. Secretary of the Interior’s Standards Pursuant to Development Code Section 17.18.040(E)(1)(c), “the Historic Preservation Commission shall only approve an application for a certificate of appropriateness if the project is consistent with the secretary’s standards.” The project is consistent the Secretary of the Interior’s Standards for the treatment of historic properties, specifically the standards for rehabilitation. The applicable standards are as follows: •Standard 2: The historic character of a property shall be retained and preserved. The removal of distinctive materials or alteration of features, spaces, and spatial relationships that characterize a property will be avoided. The applicant proposes to install a composite material that closely mimics the appearance of traditional wood while maintaining the historic character of the porch. All other elements of the existing porch, such as the turned wood columns, and all other character-defining features of the existing structure, such as the steep-pitched shingled mansard roof and unelaborated dormers and windows, shall remain as is. •Standard 5: Distinctive materials, features, finishes, and construction techniques or example of craftsmanship that characterize a property shall be preserved. The new composite material will closely match the original wood material in appearance, color, and dimension. The applicant selected to use the “Basics” line from the “Trex Enhance” composite decking product, which features a wood-like grain pattern. The character-defining elements of the porch, such as the balustrade, turned porch posts, and wooden skirting, are to remain fully preserved. •Standard 6: Deteriorated historic features shall be repaired rather than replaced. Where the severity of deterioration requires replacement of a distinctive feature, the new feature shall match the old in design, color, texture, and where possible, materials. Replacement of missing features shall be substantiated by documentary and physical evidence. While the decking of the existing porch may not be considered a distinctive feature of this architectural style, in an abundance of caution, the applicant has documented the advanced deterioration of the wood decking and proposed a composite alternative that closely matches the original in design, color, and texture while offering improved durability. The use of “Trex Enhance” composite decking for the Chaffey-Isle House rehabilitation aligns with historic preservation standards while offering durability, sustainability, and low maintenance. Made from 95% recycled materials, it mimics natural wood with authentic grain textures and historically compatible colors. Its moisture, rot, and insect resistance ensure longevity, reducing upkeep costs. With dimensions like traditional wood, it integrates seamlessly without altering the Chaffey-Isle House’s historic proportions. This choice balances preservation and modern    Page 11 Page 5 of 6 2 7 4 2 performance, making it an ideal substitute for traditional wood decking. Environmental Assessment The Planning Department staff determined that the project is categorically exempt from the requirements of the California Environmental Quality Act (CEQA) and the City’s CEQA Guidelines. The project qualifies as a Class 1 exemption under State CEQA Guidelines Section 15301 – Existing Facilities, which consists of the operation, repair, maintenance, permitting, leasing, licensing, or minor alteration of existing public or private structures, involving negligible or no expansion existing or former use. Specifically, this includes the restoration or rehabilitation of deteriorated or damaged structures and facilities to meet current standards of public health and safety. Additionally, the project qualifies as a Class 31 exemption under State CEQA Guidelines Section 15331 – Historical Resource Restoration/Rehabilitation. The project scope is to rehabilitate the porch of a historic property by replacing all 620 square feet of the wood porch decking to a substitute composite material, “Trex Enhance” composite decking. There is no substantial evidence that the project will have a significant effect on the environment. Public Art Per Section 17.124.020.A of the Development Code, public art requirements do not apply to Certificates of Appropriateness and are applicable only to Site Development Review, Minor Design Review, or Design Review applications that meet specified criteria. As such, the Certificate of Appropriateness is exempt from the public art requirement. Correspondence This item was advertised as a public hearing with a regular legal advertisement in the Inland Valley Daily Bulletin newspaper on February 26, 2025. Notices were also mailed to a total of 635 property owners within 660 feet of the site on February 25, 2025. The site was posted on February 26, 2025. As of date, staff has not received any public comment. FISCAL IMPACT: The lease between the City of Rancho Cucamonga and the Etiwanda Historical Society requires the maintenance and repair of the premises in good condition and repair at the Etiwanda Historical Society’s sole cost and expense. A well-maintained historical site attracts visitors, benefitting local businesses and increasing sales tax revenue. In addition to providing historical education opportunities and enhancing community identity, the rehabilitation also supports employment in preservation, tourism, and event management sectors. COUNCIL MISSION / VISION / VALUE(S) ADDRESSED: The project supports the Council’s core values of providing and nurturing a high quality of life for all, in addition to working together cooperatively and respectfully with each other, staff, and all stakeholders. The rehabilitation of the porch for the Chaffey-Isle House, a historic property will contribute to preserving the history of the neighborhood. In addition to the preservation of Historic Etiwanda’s history, the structure offers the community a gathering space for events, access to cultural education, and a sense of belonging. The issuance of this Certificate of Appropriateness demonstrates a cooperative and respectful relationship between the City and the Etiwanda Historical Society.    Page 12 Page 6 of 6 2 7 4 2 EXHIBITS: Exhibit A – Estimates for Chaffey-Isle House Porch Replacement Exhibit B – Preservation Brief - The Use of Substitute Materials on Historic Building Exteriors Exhibit C – Draft Resolution HPC_2025-001 with Conditions of Approval    Page 13    Page 14 1 16 PRESERVATIONBRIEFS The Use of Substitute Materials on Historic Building Exteriors John Sandor, David Trayte, and Amy Elizabeth Uebel National Park Service U.S. Department of the Interior Technical Preservation Services The Secretary of the Interior's Standards for Rehabilitation generally require that deteriorated distinctive architectural features of a historic property be repaired rather than replaced. Standard 6 of the Standards for Rehabilitation further states that when replacement of a distinctive feature is necessary, the new feature must “match the old in composition, design, color, texture, and other visual properties, and, where possible, materials” (emphasis added). While the use of matching materials to replace historic ones is always preferred under the Standards for Rehabilitation, the Standards also purposely recognize that flexibility may sometimes be needed when it comes to new and replacement materials as part of a historic rehabilitation project. Substitute materials that closely match the visual and physical properties of historic materials can be successfully used on many rehabilitation projects in ways that are consistent with the Standards. The flexibility inherent in the Standards for Rehabilitation must always be balanced with the preservation of the historic character and the historic integrity of a building, of which historic materials are an important aspect. Any replacement work reduces the historic integrity of a building to some degree, which can undermine the historic character of the property over time. With limited exceptions, replacement should only be considered when damage or deterioration is too severe to make repair feasible. When needed replacement is made with a material that matches the historic material, the impact on integrity can be minimal, especially when only a small amount of new material is needed. When a substitute material is used for the replacement, the loss in integrity can sometimes, although not always, be greater than that of a matching material. Also, whether historic or substitute material, there is a point where the amount of replacement can become excessive and the building’s historic integrity is diminished to an unacceptable degree, regardless of the material used—that is, a loss of authenticity and the physical features and characteristics closely associated with the property’s historic significance. The term substitute materials is used to describe building materials that have the potential to match the appear- ance, physical properties, and related attributes of historic materials well enough to make them alternatives for use in current preservation practice when historic materials require replacement. Compelling reasons to use a substitute material instead of the historic material include the unavailability or poor performance of the historic material, or environmental pressures or code-driven requirements that necessitate a change in material. When using a substitute material for replacement it is critical that it match the historic material in all of its visual and physical properties to preserve the historic character of the building and minimize the impact on its integrity. Substitute materials can be cost-effective, permit the ac- curate visual duplication of historic materials, and provide improved durability. While the behavior of traditional, his- toric materials is generally well understood, the behavior of newer materials can be less established and sometimes less predictable. Substitute materials are most successful when the properties of both the original material and the substitute are thoroughly understood by all those involved in the design and construction process. The architect must be adept at the selection of substitute materials and their incorporation into architectural plans and specifications. The contractor or tradesperson in the field must also be experienced with their use. This Preservation Brief provides general guidance on the use of substitute materials as replacement materials for distinctive features on the exterior of historic buildings. Due to the ever-evolving product market for construction materials, this Brief does not provide specifications for substitute materials. This guidance should be used in conjunction with qualified professionals who are knowledgeable in current construction and historic preservation practices. Exhibit B   Page 15 2 This Brief includes a discussion of the appropriate use of substitute materials and provides a path for decision- making in their use. In considering the use of substitute materials, such issues as the deterioration or failure of the historic building component and material must be understood. The existing component’s physical and visual properties, profile, surface texture, dimensions, and performance should be identified to establish the basis for evaluating a possible replacement material. The physical and visual properties of the various substitute materials available should also be assessed and compared to the original material for their physical and visual compatibility. Lastly, the suitability of a given substitute replacement material should be determined based on how well the material matches both the physical and visual properties of the existing material as well as any specific performance or application needs. The Brief’s descriptions of common substitute materials are not meant to be comprehensive, and, as the performance history of newer materials continues to grow and new materials are developed, available options will change, and our understanding of current material performance will continue to evolve. Historical Use of Substitute Materials The tradition of using affordable and common materials in imitation of more expensive and less available materi- als is a long one. At Mount Vernon, for example, George Washington used wood painted with sand- impregnated paint to imitate rusticated stone. This technique, along with scoring stucco into block patterns, was common in Colonial America to imitate stone. Nineteenth-century technology made a variety of materi- als readily available and widely used that were not only able to imitate traditional materials but were also cheaper to fabricate and easier to use. Traditionally, carved stone units were individually worked. Molded or cast materials greatly increased efficiency in creating repetitive ele- ments. Cement-based products such as cast stone could provide convincing imitations of natural stone with care - fully chosen aggregates and cements and was typically a commercially manufactured product. It could be tooled like natural stone, though that could reduce much of the cost advantage. These carefully-crafted cementitious products were widely used as trim elements for masonry structures or as the face material for an entire building. At the other end of the spectrum, mail-order catalogs provided a wide variety of forms for molding concrete that were merely evocative of natural stone and did little to match its appearance. Concrete masonry units could be fabricated locally and on site, avoiding expensive quarry- ing and shipping costs. Offering similar efficiencies as cast stone for reproducing repetitive and even complex decorative shapes, terra cotta could mimic the surface characteristics of stone with vari- ous textures and glazes. It was popular in the late nine - teenth and early twentieth centuries for details on stone or brick buildings as well as for the entire skin of large and elaborately detailed buildings. Cast iron was also used to imitate stone, often with very decorative profiles, for a variety of architectural features ranging from window hoods to columns, piers, balus- trades, and even whole façades. Cast iron offered its own set of efficiencies including cost, fabrication time, and weight, but required a painted finish. While cast stone, terra cotta, and cast iron offered effi- ciencies over quarried and, particularly, carved stone, they were not cheap or impermanent materials. Less costly, but also less durable, stamped or brake-formed sheet metal, typically galvanized, could also be used instead of masonry for cornices, window hoods, roofing tiles, and even entire building façades. Substitute Materials and Applying the Standards for Rehabilitation The Standards for Rehabilitation are focused on preserving the important and distinctive character-defining features of a historic property (Standards 2 and 6), and they are to be applied in a reasonable manner, taking into account economic and technical feasibility (36 CFR 67.7 and 36 CFR 68). The Standards have an inherent flexibility that facilitates their application to diverse projects, historic properties, and conditions. They are to be applied on a “cumulative-effect” basis, when the overall effect of all work in the context of the specific conditions of the property and the project is consistent with the property's historic character. The Standards for Rehabilitation require that the replacement of a distinctive feature match the old in physical and visual properties. While the use of matching materials is always preferred, the Standards purposely allow for the use of substitute materials when the use of original materials is not reasonably possible, such as in consideration of economic and technical feasibility or in new construction. They also provide additional flexibility in the treatment of secondary, less distinctive features that are less important in defining the historic character of the property. The Standards for Rehabilitation recognize that flexibility is appropriate to facilitate “a compatible use for a property … while preserving those portions or features which convey its historical, cultural, or architectural values” (definition of “Rehabilitation,” 36 CFR 67.2(b)).    Page 16 3 Examples of Historical Use of Substitute Materials Figure 2a. Casting concrete blocks to mimic quarried stone was a popular late 19th- to mid 20th-century technique. Concrete masonry units could be completed by local craftsman, saving time and shipping costs. Photo: John Sandor, NPS. Figure 2b: The 19th century also produced a variety of metal products used to imitate other materials. Across the country, cast iron was used in storefronts to imitate stone. Photo: John Sandor, NPS. Figure 2c: Stucco has been used to imitate a number of building materials for many centuries. Seen here, stucco was applied to a brick structure and scored to represent a stone façade. Photo: John Sandor, NPS. Figure 2d: Terra cotta gained popularity in the late 19th century as a cheap and lightweight alternative to stone. Glazing techniques allowed the blocks to imitate a variety of natural stone materials. Photo: John Sandor, NPS.    Page 17 4 These examples of one material used to imitate another, more often in initial construction than for later repair and replacement purposes, are referred to as imitative materi- als in the Guidelines for Preserving, Rehabilitating, Restor- ing & Reconstructing Historic Buildings, updated in 2017, that accompany the Secretary of the Interior's Standards for the Treatment of Historic Properties. These imitative materials, while evoking other materials, usually had dis- tinctive qualities of their own and were not always a very close match in appearance to the historic material they were meant to imitate. Many of the traditional materials discussed above are still available and used to replace damaged or missing original features, both to replace matching historic materials and sometimes as substitute materials. Because of their exten- sive use over time and their known physical and chemical properties, cast stone, cast iron, and terra cotta are well understood substitute materials. This continued usage and familiarity means their installation requirements and service life are well established, which in turn makes it easier to determine when and how to use these traditional materials as substitutes for a deteriorated material. Howev- er, innovation in replacement materials continues, and new products (many of them consisting of synthetic materials) are continually introduced. These non-traditional products are an increasing part of both the new construction and rehabilitation industries. Some materials, like glass fiber reinforced polymers, glass fiber reinforced concrete, or fiber cement, have been in use long enough for an accu- rate prediction of their service life and performance. Other newer, non-traditional materials may be too new to have established performance records, thus, understanding their material properties is critical, and their use should be approached with more caution. When to Consider Using Substitute Materials in Preservation Projects According to the Standards for Rehabilitation, deteriora- tion should generally be addressed through repair if in repairable condition. Repair can entail a variety of treat- ments that retain the unit of building material and remove and patch or replace only the damaged portion. This ap- proach can be done with traditional methods and materi- als such as a dutchman, where like-kind material is pre- cisely inserted into wood or stone, or it may employ other materials such as epoxies for wood repair or cementitious compounds for masonry. As long as the repair methods are sound and do not damage or accelerate the deterioration of the historic material, repairs are generally preferable to replacement of an entire element. More complex manufac- tured products, typical of more recent historic materials (as well as a lot of modern building materials generally), may be more difficult to repair, if they can be repaired at all. There are situations, however, when the level of deterio- ration makes localized repairs infeasible and entire fea- tures or units of historic material must be replaced. While achieving an effective match of all of the visual qualities of a material can be challenging, even when replacement is in kind, it can be even more challenging when the replace- ment is a substitute material. A good visual match is not the only consideration when a substitute material is to be used for incremental replacement within a larger assem- bly of historic material. When an individual siding board or a single block of ashlar is being replaced, it is usually best achieved with the original material. Introduction of a different material into an intact assembly requires that its inherent properties, such as expansion and contraction, moisture resistance, or permeability, be thoroughly consid- ered relative to those of the surrounding historic materials to avoid causing damage. Figure 3: Incremental repair is best done using in-kind material to minimize differences in the performance characteristics that could negatively affect the overall assembly. Photo: NPS. Figure 4. While occasionally used to imitate other materials such as wood or slate shingle, many asbestos shingles and siding materials had their own distinct shape and profile. No longer manufactured today, alternative materials must be found to replace these materials when they are distinctive features on a historic structure. Drawing: Association for Preservation Technology, Building Technology Heritage Library.   Page 18 5 Figure 5. (Left) Asbestos shingles were often used as a substitute for traditional slate roof shingles. The historic asbestos roof on this rehabilitation project had reached the end of its lifespan and required complete replacement. (Right) Given the limited replacement materials available to match the historic asbestos shingles, utilizing natural slate was determined to be the best visual match for the original shingles and design intent in this instance. Photos: Crosskey Architects. Circumstances in which the use of substitute materials may generally be considered appropriate, taking into consideration technical and economic feasibility reasons, include: the unavailability of historic materials; the unavailability of skilled artisans or historic craft techniques; inadequate durability of the original materials; the replacement of a secondary feature; construction of a new addition; the reconstruction of a missing feature; code-required performance; and for enhanced resilience and sustainability: • Unavailability of historic material. A common reason for using substitute materials is the difficulty in finding a good match using the historic material (particularly a problem for masonry materials where the color and texture are derived from the material itself). This may be due to the actual unavailability of the material or to protracted delivery dates, particularly if the material cannot be sourced domestically. It is not uncommon for a local quarry that is no longer in operation to have been the source of an original stone. If another quarry cannot supply a satisfactory match, a substitute material such as dry- tamp cast stone or textured precast concrete may be an appropriate alternative, if care is taken to ensure that the detail, color, and texture of the original stone are matched. Even when the color is successfully matched, the appearance of a cementitious product may diverge from that of the historic stone as the substitute material ages. Many manufactured materials that were used historically on buildings are no longer made. Terne- plated steel, which was the material most typically used for painted standing-seam or flat-seam roofing, is no longer made. However, because it was always painted, other metals including galvanized steel or copper can generally be substituted if painted. When the historic material needing to be replaced is a manufactured product developed as an imitation of a natural material, which was the case with asbestos shingles meant to imitate slate, the natural material may now be an appropriate substitute material to consider for the manufactured one that is no longer produced. • Unavailability of skilled artisans or historic craft techniques. These two issues can complicate any preservation or rehabilitation project. This is particularly true for intricate ornamental work, such as carved wood, carved stone, wrought iron, or cast iron. While skilled craftsmen may not be as difficult to find as they once were, there can still be limitations geographically, even in finding less specialized skills, and particularly if a project is small. Technical advances have allowed some stone or wood carvers to take advantage of computerized equipment, but complex designs will likely still require hand work. It may also be possible to mimic a carved element using a material that can be cast in a mold, adding significant efficiency where an historic element survives from which a mold can be made. Options for casting include aluminum, cast stone, fiberglass, glass fiber reinforced concretes, and terra cotta, but not all carved elements can be duplicated by a casting, and mold-making and casting still require skilled craftsmen. • Inadequate durability of the original material. Some historic building materials were of inherently poor quality or were not durable. In other cases, one material was naturally incompatible with other materials on the building, causing staining or galvanic corrosion. Examples of poor-quality materials are very soft sandstones, which eroded quickly, and brownstone, which is vulnerable to delamination. In some cases, more durable natural stones may be visually similar enough to stand in for these soft stones but cast stone or another material may be needed to achieve an appropriate match.    Page 19 6 Figure 6. The dramatic difference in the number of growth rings between old-growth wood and wood that was recently harvested from second- or third-growth forests is indicative of the diminished dimensional stability and durability of most lumber currently available. Photo: Zachary Dettmore. The ready availability of manufactured ornamental wood features fed a nineteenth-century taste for decorative architectural details that were often used on the exterior of buildings with little concern for how they would be affected by moisture or maintained. Even old-growth wood from decay- resistant species often could not prevent features with severe exposure from eventually needing to be replaced. Today’s available commercial supplies of lumber no longer provide the denser, more decay- resistant wood of old-growth forests, so even careful matching to species, which is not always possible, will not yield a replacement equal in performance to the historic material. Old-growth wood is likely to be very expensive, if it can be found, and may not be available from a sustainable, environmentally responsible source. When features with severe exposure need to be replaced or reproduced, substitute materials that are less susceptible to decay can have a longer life, and when the feature is painted, as exterior wood features generally are, the visual effect of a substitute material can be minimal. • Replacement of a secondary feature. When it is necessary to replace a less distinctive, secondary feature that is less important in defining the historic character of the property, there is more flexibility in how it can be replaced. While it may be less important to find an exact match in materials when replacing such a feature, the retention of the overall historic character should still guide selection of an appropriate replacement material. For example, replacing secondary features such as those with limited visibility (e.g., siding materials on a rear elevation) may permit replacement materials that are similar in appearance or character without having to be a perfect match. • Construction of a new addition. The Standards require that new additions to historic buildings and related new construction be differentiated from the old as well as be compatible with the historic character of the property and its site and environment. Using materials that evoke, without matching, the historic material can be an effective means of achieving the needed balance between compatibility and Figure 7. A new addition replaced non-historic construction on the rear elevation of this building. Fiber cement gives the addition a compatible appearance without replicating the exposure for thickness of the historic siding. Photo: Ward Architecture + Preservation.    Page 20 7 Figure 8. A long-missing cast-iron steeple was reconstructed in aluminum and fiber-reinforced polymer (FRP). Photo: John Sandor, NPS, Inset: Quinn Evans. differentiation for new additions and new construction. Even if differentiation is achieved through design rather than materials, there generally is no basis for requiring the use of matching historic materials for new additions and new construction as part of a rehabilitation project. • Reconstruction of a missing feature. Many buildings lose significant features over the course of their lives for reasons such as those previously discussed. When a missing feature is to be reconstructed, the importance of matching the original mate- rial may be less important to the effect replacing the missing feature may have on the overall historic character and appear- ance of the building. Though replacement of missing features must be substantiated by documentary, physical, or pictorial evidence, in many cases the authenticity of the material may be secondary to the overall visual qualities. The use of a more cost-effective substitute material for the construction of a missing feature can often be an important factor in the feasibility of undertaking such work. • Code-required performance. Modern building codes are regularly amended to require higher performance levels for new and existing buildings in such areas as life safety, seismic retrofits, and accessibility. Rehabilitation projects often trigger compliance with code requirements that were not in place when a building was constructed. Although building codes may often allow for the retention of historic materials and assemblies, substitute materials can offer an alternative in situations when the historic materials are non-compliant and cannot otherwise be reasonably retained. In these instances, a change in material may be appropriate to meet code requirements, while in other instances selecting the optimal code compliance method for the project may achieve code-compliant solutions that also allow for the preservation of a building’s historic materials and finishes. For example, fire codes may require increased resistance to flame spread for buildings within dense urban environments where building proximity and separation between buildings is a concern. Some substitute materials are non-combustible, have good ratings for flame spread, and can provide an alternative to help meet    Page 21 8 fire code requirements. Depending on the building component and the material, however, a substitute material may not resist fire any better than the historic material. In addressing code issues, all feasible alternatives should be considered to minimize the impact on the historic character of the building while still meeting code requirements. With specific provisions in building code related to issues such as seismic hazards, the choice of materials for features inherently unstable in a seismic event can be a key part of a code-compliant retrofit solution. Elements at risk of falling such as parapets, finials, and overhanging cornices may be made safe by anchoring them to new structural frames. However, for some heavy masonry features, especially where there is deterioration or the feature is difficult to effectively brace, adequately anchoring the existing feature may not prove feasible. In such cases removing and replacing these features with lighter-weight replicas that incorporate a resilient structural framework can help preserve the historic character of the building while improving life safety performance. • Enhanced resilience and sustainability. Wildfires, earthquakes, floods, hurricanes, and other extreme weather events put historic buildings and their occu- pants at risk and may require adaptive treatments that are more invasive than might be accepted in other cir- cumstances, including related to the use of substitute materials. In these contexts, it is still necessary to try to minimize impacts on a building’s historic character as much as possible while still adapting it to be more resilient. Widespread wildfires, for example, have increased demand for fire resistant materials for the exterior building envelope. Flood events may neces- sitate the replacement of historic materials that have been damaged or inundated with hazardous substanc- es in contaminated floodwaters. When undertaking repairs in such circumstances, substitute materials may offer greater resilience to anticipated future exposure to natural hazard risks. Similarly, efforts to improve energy efficiency and performance may include the use of substitute materi- als as replacement components when modifications to building assemblies are required and the historic mate- rials cannot be preserved. When evaluating substitute materials in the context of sustainability objectives, factors such as the environmental impact of produc- tion, the full life cycle of products, and the embodied carbon of the materials already in place should be carefully analyzed. There may be more sustainable choices for a replacement material, including the use of more traditional materials in place of manufactured products that may consist of non-renewable resources or hazardous materials. While some synthetic substi- tute materials are made from recycled materials or are otherwise sustainably produced, many are not repairable, salvageable, or recyclable themselves, and they may have shorter lifespans to their historic mate- rial counterparts. When either greater resilience or sustainability is a factor, all feasible alternatives should be considered in finding a balanced approach that maintains historic character while meeting resilience and sustainability goals. Substitute Materials and Economic Feasibility Economic feasibility is inevitably a concern when choosing a material for any part of a project, whether a historic or substitute material, but it should not be the sole determinant factor at the expense of maintaining the Figure 9. Previously bricked-in openings below the flood line were reopened and new aluminum windows installed with cellular PVC trim detailed to hold back moderate flood waters and survive exposure to water. Photo: John Sandor, NPS. historic character and historic integrity of a building. Other factors may prompt the consideration of a substitute material, such as the cost of maintaining the historic material, because it is comparatively difficult or costly to reach or access, or the frequency of required maintenance the historic material needs. Additionally, where in- kind replacement material is found to be prohibitively expensive, it may be reasonable to consider a substitute that offers an alternative and is a good physical and visual match. Not all substitute materials are, however, cost-effective replacements. Long-term durability and maintainability are other factors that should be considered in conjunction with initial cost. Maintenance of a material, particularly where accessibil- ity is difficult or expensive, can be an important part of a    Page 22 9 cost evaluation. Maintenance costs should not be consid- ered without also considering life-cycle expenses. While some substitute materials may offer reduced initial costs, they may be as or more costly than traditional materials to maintain over time. For example, many substitute materials are not readily repairable, necessitating full replacement when damaged. The cost to replace a material or assem- bly at the end of its lifespan may also be greater than the accumulated incremental expense to maintain the historic material, particularly if it is a more traditional, repairable material. Maintenance cost should never be the sole reason for replacing a historic material that is not deteriorated. Criteria for the Appropriate Use of Substitute Materials Substitute materials must meet three basic criteria to be considered: they must be compatible with the historic materials in appearance; their physical properties must be similar to those of the historic materials, or the materials must be installed in a manner that tolerates differences; and they must meet certain basic performance expecta- tions over an extended period of time. •Matching the Appearance of the Historic Material Any material’s appearance varies depending on the nature of the material and how it is used. Some historic materials, such as wood and ferrous metals, were typically painted, making the color of the substitute unimportant, though the texture of the surface, which telegraphs through a paint layer, is still an important consideration. Texture can be a large part of distinguishing a material formed by hand from one that is machine-made. Many historic materials, such as most building stones, are used without any coating, making the color, pattern, and reflectivity, as well as surface texture, dependent on the material itself. Matching the color and surface characteristics of a historic natural material with a man-made substitute can often be quite difficult. When the color and surface characteristics of an existing material are important, cleaning the material should be the starting point for evaluating a potential matching material. In situations where there are subtle variations in color and texture within the original material, the substitute material should be similarly varied so that it is not conspicuous by its uniformity. If a material is custom fabricated, a sufficient number of samples should be supplied to permit on-site comparison of color, texture, detailing, and other critical visual qualities. For a manufactured product with preset choices of color or texture, it may be necessary to look at samples from more than one manufacturer to find the best match. Similarly, prefabricated products, such as roofing slate, may offer limited, if any, choice of unit size, which can be a critical factor for achieving a good match. A substitute material should not be used to replace distinctive, character- defining materials and features if an adequate match in design and appearance is not possible. As all exposed materials are subject to ultraviolet degradation, samples of a new material, particularly when custom formulated, should be prepared during the early planning phases to allow for evaluation of the effects of weathering on color stability. When that is not possible, or if a prefabricated product is used, the fabricator or manufacturer may be able to identify regional locations where equivalent products have been installed long enough ago to get a better sense of how the material weathers and performs. While a perfect match is the desired goal for replacing distinctive features, it is not always possible, even when the same matching material is chosen for the replacement. When any compromise Figure 10. Polymer slates offer a choice of shapes but not sizes, limiting their ability to achieve a good visual match for some historic slate. With the size of the polymer slates (right) being nearly twice that of the historic slates (left), the scale of the entire feature is incompatibly altered. The molded edges of this mate- rial, which contribute to its ability to replicate slate, would be lost if each shingle was resized by cutting. Photo: John Sandor, NPS.    Page 23 10 must be made in the precision of the match, it is wise to consider the vantage point from which the material will be seen. Sometimes what seems important at close range, such as variations in the texture of a surface, may be secondary to other aspects of the material when viewed from some distance. The closer a feature is to the viewer, the more closely the material and craftsmanship should match the original. An on-site mock-up using a sample of the proposed material can help evaluate whether it is an adequate visual match. Figure 11. The thickness of the wood siding on the front (left) creates a deeper shadow line than is achieved with the fiber cement siding used on the side (right) elevation. While the exposure can be adjusted, fiber cement siding is not available in a matching thickness. Photo: John Sandor, NPS. • Matching the Physical Properties of the Historic Material Carefully chosen substitute materials can often closely match the appearance of historic materials, but their physical properties may differ greatly. These differences are most critical when incrementally replacing components of a larger assembly that retains significant historic material. The chemical composition of the material (e.g., the presence of acids, alkalis, salts, or metals) should be evaluated to ensure that the replacement materials will be compatible with the adjacent historic materials. Materials that will cause galvanic corrosion or other chemical reactions must be isolated from one another. The thermal- and moisture-driven expansion and contraction coefficients of each adjacent material must be within narrow limits or be accommodated by carefully designed joints and fasteners. Joints can play a role both in accommodating movement of materials as well as in managing moisture, either to keep it from entering the enclosure assembly or to let it escape from the building envelope, or both. Because some synthetic materials are less permeable to moisture than more traditional materials, installations must take into account the potential to trap moisture and cause deterioration of historic and new materials. An assembly incorporating new and historic materials should be designed so that if material failures occur, the failures occur within the new material rather than the historic one. During installation, surface preparation is critical to ensure proper attachment. Deteriorated underlying material must be removed or stabilized. Non- corrosive anchoring devices or fasteners that are designed to carry the new material and to withstand wind, rain, snow, and other destructive elements should be used. Since physical failures often result from poor anchorage or improper installation techniques, a structural engineer should be included in planning any major project. For readily available, off-the-shelf materials, manufacturers’ recommendations for attachment and spacing should be followed. Nearly all substitute materials have some properties that are different from the historic materials they may replace. Even when substitute materials are isolated from historic materials and features, it is important to understand the substitute materials’ properties in order to use them successfully. • Performance of the Material Over Time When more traditional materials are used to replace damaged historic materials and features, their perfor- mance is predictable in most cases. An exception may be modern wood that has durability and other prop- Figure 12. Cellulose composite materials, like wood, expand and contract with moisture. Here it was used to reconstruct a missing storefront. Unlike solid wood that is dimensionally stable parallel to the grain, this composite moves equally in all dimensions, resulting in gaps that were not adequately anticipated in the design. Photo: John Sandor, NPS.    Page 24 11 Figure 13. Cast stone was used to effectively replace individual blocks of sandstone. Both the original ( left) and the substitute material (right) retain similar physical and visible properties. Having weathered for over 30 years, some erosion of the binder has revealed quartz grains of the aggregate (inset), but it is only noticeable upon close inspection. Photo: John Sandor, NPS. erties different than those of historic wood from old- growth forests. Many of the materials used as substi- tutes have been in use long enough to provide some idea of how they perform over time. Other material may only have test results from accelerated weather- ing. The length of manufacturer warranties may be an indicator of expected durability and lifespan. War- ranties only predict a manufacturer’s expectation of a product’s performance and are no guarantee that the manufacturers will still be in business at the time needed to stand behind them. Just as new manufac- turers emerge with new materials, others disappear. Where possible, projects involving substitute materi- als in similar installations and exposures should be examined before selecting a new, less-tested material. It is unrealistic to expect a substitute material, which can be quite different in composition than the historic material, not to age differently. Even traditional materials will not perform well if not used or detailed appropriately, and experienced architects, engineers, fabricators, and installers rely on their professional knowledge and experience to ensure proper installation and techniques when work- ing with familiar materials. This is just one of many reasons that using the original materials for needed replacement is usually the best choice. Some of the materials now available as substitutes have properties that differ greatly from the traditional materials they may be used to replace. It is critical to the successful performance of substitute materials that everyone involved in the selection, design, and installation fully understands the material’s properties, especially how it is different than the material it is replacing, and how that will affect the surrounding materials and building systems. Many traditional building materials can be repaired either with traditional methods and materials or with more modern conservation techniques using sub- stances like epoxies. However, many modern substitute materials (particularly synthetic ones) are not as easily repaired, if repairable at all, as their more traditional counterparts. Confirming that a material is repairable may be important for those used, e.g., where impact or significant wear or abrasion is likely. Finally, it is critical that the substitute materials be documented as part of the historical record of the building so that proper care and maintenance of all of the building materials continue, ensuring the contin- ued life of the historic building. Choosing an Appropriate Substitute Material Once all reasonable options for repair and replacement in kind have been considered and sufficient justification for substitute materials has been established, the choice among the variety of substitute materials currently available must be made. Rapidly developing technologies allow a wide variety of materials to choose from that are intended to mimic historic materials. Many of the materials that were historically used as substitutes for more traditional historic materials have themselves become historic, and some of these early substitutes continue to be reasonable options as substitute materials today. No substitute material will exactly match the historic material in all aspects, but many are able to adequately match the appearance and relevant physical attributes to make for a potential substitute. If a substitute material is not    Page 25 12 an adequate physical and visual match given the specific conditions of the building and the project, then it should not be used to replace distinctive, character-defining materials and features. Listed below are various building components or features and the substitute materials which may, in some circumstances, be considered for use as possible replacement materials in a historic rehabilitation project consistent with the Standards for Rehabilitation. This list includes different substitute material options available today for these building features and poses questions that should be asked and considered when choosing between the original material and various types of substitute materials. This is followed by a list of some of the more commonly used, currently available materials that may have some applications as substitute materials and the properties of each that affect their suitability for use as substitutes. This list should not be read as an endorsement of any of these materials, generally, or their appropriateness for use as a substitute material, but it serves as a reminder that the successful use of any building material requires a careful consideration of its properties relative to where and how it will be used. The above chart lists materials that are sometimes used as substitutes for replacement of historic building features. Even within a given category, all materials may not be equally suitable as a substitute replacement material for the actual historic material or feature. Any substitute material should be selected based on its specific physical and visual characteristics, conditions, and intended application consistent with the Secretary of the Interior's Standards for Rehabilitation. Masonry Stone, terra cotta Architectural Metals Cast & wrought iron, steel, pressed metal Siding Wood, asbestos Roofing Wood shingle, slate, tile Decking Tongue-and- groove & square-edge wood Molding / Trim Wood Aluminum •••• Cast Stone & Precast Concrete •• Fiber Reinforced Concretes • Glass Fiber Reinforced Polymers •• Fiber Cement ••• Mineral / Polymer Composite •••• Cellulose Fiber / Polymer Composite •••• Non-composite Polymers ••• Cellular PVC •••Po t e n t i a l S u b s t i t u t e M a t e r i a l s Historic Building Features Considering Substitute Materials Considering the use of a substitute material should begin with the following questions about the conditions and location where it will be used: • Will the significance or visibility of the historic feature require a very precise match? • Is the entire feature being replaced or just a component of it? • Are pre-existing conditions contributing to the failure of the existing material, and, if so, how will they be addressed/corrected? • Is the need for replacement due to inherent deficiencies of the original material? • Will the material need to resist any environmental hazards such as flooding or fire? Historic Features and Substitute Materials Historic Building Features    Page 26 13 Historic Building Features: Criteria for selecting an appropriate replacement material Masonry FEATURES: corbels, brackets, balusters, cornices, window and door surrounds, friezes, wall surfaces, horizontal surfaces, incidental ornament, columns HISTORIC MATERIALS: terra cotta, cast stone, stone, concrete POTENTIAL SUBSTITUTES: cast stone, pre-cast concrete, GFRC, GFRP, non-composite polymers (polyurethane), cast or stamped metal Questions to ask about the replacement material: • • • • • • • • • • • • Can it serve a structural function? How is the material affected by moisture? Can the material survive flooding and be reused? Can it reproduce the surface texture of the original? Is its shrinkage in curing low enough to allow it to be molded from existing stones? Can matching color be achieved without a coating and with UV stability? Can an adequate match of the surface (color and texture) be achieved with a coating? Is a coating required? If it is not self-supporting, is it lightweight enough to be supported by an underlying framework? Can multiple original units be replicated with a single replacement piece? Where thermal movement is different from the original material, how will joints accommodate? Is the material combustible? Architectural Metals FEATURES: pilasters, door and window surrounds, cornices, incidental ornament, columns, spandrels, ceilings, sheathing, roofing HISTORIC MATERIALS: cast and wrought iron, steel, bronze, lead, aluminum, and stamped steel (usually galvanized or terne-coated) POTENTIAL SUBSTITUTES: GFRP, aluminum, non-composite polymer (polyurethane), GFRC, metallic/polymer composite Questions to ask about the replacement material: • • • • • • • • Will the replacement material serve a structural or cosmetic role? Will it expand and contract with temperature change enough to require special accommodation in its installation? If part of an assembly of mixed materials, how will any expansion and contraction of the dissimilar materials be accommodated? Will the replacement material increase deterioration of the historic or surrounding elements, for instance due to galvanic corrosion, moisture entrapment, jacking of original material, off-gassing creating a corrosive environment, or poor original design of the historic material? How will the replacement material mimic the surface color/patination of the original material? If a coating is needed, what preparation is needed, and what is its durability or service life of the finish? What attachment and support systems are necessary? If the original element is structural, but the new material is not, how can supplemental structure be introduced to support the new?    Page 27 14 Figure 14. Surface texture is an important aspect in matching the appearance of a historic material, especially when a material is viewed at close range. As seen in these two images, many of the substitute materials produced for siding and trim have an embossed wood grain, making them incompatible for replacing historic wood that was typically planed to a smooth surface. Some substitute products are available with a smooth surface as well. Photos: John Sandor, NPS. Siding FEATURES: clapboard, tongue-and-groove or shiplap siding, board and batten, shingles HISTORIC MATERIALS: wood and asbestos POTENTIAL SUBSTITUTES: cellular PVC, wood fiber/ polymer composite, fiber cement, mineral/polymer composite Questions to ask about the replacement material: • • • • • • • • • • • • • What are the widths, lengths, profiles, thicknesses, and textures available? What, if any, are the finishing requirements, and/or is it available factory-finished? How well does it hold paint, and can prefinished surfaces be renewed? What tools are needed to cut it, and can it be machined? Does it absorb moisture and, if so, to what effect? Can the material survive flooding and be reused? Will it expand and contract with temperature change enough to require special accommodation in its installation? What characteristics can affect its handling (e.g., weight, flexibility, brittleness)? Does it have specific fastening requirements? Is it susceptible to insect damage? What is its impact resistance? Does it have a flame spread rating? What is the expected lifespan and/or warranty? Roofing HISTORIC MATERIALS: wood shingle, slate shingle, asbestos shingle, clay tile, concrete tile, metal POTENTIAL SUBSTITUTES: fiber cement, mineral/poly- mer composite, wood fiber/polymer composite, pre-cast concrete, metal Questions to ask about the replacement material: • • • • • • • • What sizes and shapes are available? What are color choices? What is the color stability of the new material, and how will it age/weather? What is the impact resistance? What is its flame spread rating? What are the installation requirements of the new material? Can the feature being replaced be custom- produced if ready-made ones of the new material are not an accurate match? What is the expected lifespan and/or warranty?    Page 28 15 Figure 15. Tongue-and- groove porch flooring is manufactured in several different substitute materials. Each type has different properties, though most are more moisture- resistant than wood. The prefinished product shown can be painted when worn, but repainting is not recommended for some product choices. Photo: Oak Alley Foundation. Decking FEATURES: tongue-and-groove, square-edge flooring HISTORIC MATERIALS: wood POTENTIAL SUBSTITUTES: cellular PVC, wood fiber/ polymer composite, mineral/polymer composite, non- composite polymers (solid PVC) Questions to ask about the replacement material: • • • • • • • • • • • • • What are the widths, lengths, and textures available? Is it site painted or prefinished? How well does it hold paint, and can prefinished surfaces we renewed? What tools are needed to cut it, and can it be machined? What dimensional span does its strength allow? Does it absorb water, and if so, to what effect? Can the material survive flooding and be reused? Does it require a drainage plane, or can it be installed atop a membrane? Will it expand and contract with temperature change enough to require special accommodation in its installation? Is it susceptible to insect damage? Is it impact resistant? Does it have a flame spread rating? What is the expected lifespan and/or warranty? Molding / Trim FEATURES: run moldings, flat boards, casings, cornice, frieze, railings, balustrade, columns HISTORIC MATERIALS: wood, metal POTENTIAL SUBSTITUTES: cellular PVC, wood fiber/ polymer composite, mineral/polymer composite, non- composite polymer (polyurethane), GFRP, sheet metal Questions to ask about the replacement material: • • • • • • • • • • • • • What are the widths, lengths, and textures available? What, if any, are the finishing requirements and/or is it available factory-finished? How well does it hold paint, and can prefinished surfaces be renewed? What tools are needed to cut it, and can it be machined? Does it absorb moisture, and if so, to what effect? Can the material survive flooding and be reused? Will it expand and contract with temperature change enough to require special accommodation in its installation? What characteristics can affect its handling (e.g., weight, flexibility, brittleness)? Does it have specific fastening requirements? Is it susceptible to insect damage? What is its impact resistance? Does it have a flame spread rating? What is the expected lifespan and/or warranty?    Page 29 • • • • • • • • • • Potential Substitute Materials: Matching properties and performance needs Physical Composition and Properties After assessing different material options based on the intended application, the appropriateness of a substitute material should also be considered in context of the material’s physical composition, associated properties, and necessary visual match. Aluminum MATERIAL: Aluminum is a highly corrosion-resistant alloy that can be cast, wrought, or extruded. Molten alu- minum is cast into permanent (metal) molds or one-time sand molds forming cast aluminum. Extruded aluminum is formed by passing heated aluminum through a die which produces the desired form. Wrought aluminum is worked using the heated metal and then bending, stamping, and otherwise shaping the metal. If not self- supporting, aluminum elements are generally screwed or bolted to a structural frame. Aluminum can be welded, but more often sections, particularly extruded ones, are mechanically connected. PROPERTIES: Isotropic Lightweight Thermal movement greater than cast iron or wood Corrosion-resistant, but direct contact with other metals may trigger galvanic corrosion Lower structural strength that iron or steel Ductile - less brittle than cast iron Non-combustible Retains high definition through molding process and produces crisp profiles through extrusion Can be given a durable metallic finish through anodization. Surface etching required for paint adhesion Can be machined into a large variety of shapes/ dimensions Figure 16. Aluminum is a highly corrosion-resistant metal that is commonly used as a substitute material for cast iron. Aluminum can be a more aordable and lightweight alternative to cast iron that retains a similar texture, shape, and maintenance cycle. Photo: NPS. 16    Page 30 Cast Stone & Precast Concrete MATERIAL : A cement lime and aggregate mixture that is dry-tamped into a mold is generally referred to as cast stone. Cast stone is one of the original substitute materials. Its longevity has proved that the material ages compatibly with stone. A wet mix of cement and aggre- gate poured into molds also has a long history of being used to produce concrete masonry units mimicking stone and roofing tiles mimicking clay tile. Both methods have minimal shrinkage during curing, though they employ different curing and finishing techniques. Both can include reinforcing bars and anchorage devices installed during fabrication. The dry-tamp fabrication method is especially effective at producing an outer surface with the appearance of stone. Figure 17. The balustrade con- sists of multiple prior campaigns of using cast stone to replace the natural stone. The eective match for the surface texture and color of the original stone allowed individual elements to be incrementally replaced only when they had failed, thus retaining the maximum amount of original material as long as possible. Photo: EverGreene Architectural Arts. PROPERTIES: • Isotropic • Weight equivalent to stone • Expansion/contraction similar to stone • Water absorption may differ from that of any particular stone • Can be structural • Non-combustible • Vapor-permeable • May achieve a wide range of color and surface textures by varying mix, but use of pigments may reduce UV stability • Can be coated • May be tooled to match the appearance of tooled stone • Repairs similarly to stone 17    Page 31 Figure 18. Missing historic terra cotta spandrel panels on all floor levels were recreated utilizing glass fiber reinforced concrete (GFRC) replacements. New spandrels were fabricated as individual components and attached with metal clips between historic terra cotta piers. Photo: Kris Frail, Dewberry. Fiber Reinforced Concretes (GFRC, CFRC) MATERIAL : Fiber reinforced concretes are lightweight concrete compounds modified with additives and rein- forced with alkaline resistant glass fibers (GFRC), or less frequently carbon fibers (CFRC). They are generally fab- ricated as thin-shelled panels and applied to a separate structural frame or anchorage system. GFRC is typically sprayed into forms, although it can be poured, and an- choring devices are included in the fabrication. The color is derived from the natural aggregates and, if necessary, a small percentage of added pigments. Because of its low shrinkage in curing, it can be produced using molds taken directly from the building. PROPERTIES: • Isotropic • Lighter weight than solid masonry • Expansion/contraction similar to stone • No load bearing capacity, so underlying framework must be used to accommodate any loads • Material can be fire-rated • Vapor-permeable • Can be produced in larger sections efficiently reproducing repetitive elements or features that were originally made up of small individual units • Large range of colors achievable by varying aggregates, but when pigments are needed UV stability may be reduced • May be left uncoated or may be painted 18    Page 32 Figure 19. A new, lightweight fiber reinforced polymer is attached to a new metal armature to replicate damaged and missing elements of a terra cotta cornice. Photo: Quinn Evans. Glass Fiber Reinforced Polymers (FRP, Fiberglass) MATERIAL : Fiberglass is the most well-known of the FRP products generally produced as a thin, rigid, laminate shell formed by pouring a polyester or epoxy resin gelcoat into a mold. When tack-free, layers of chopped glass or glass fabric are added along with additional resins. The surface gel coat can be pigmented or painted. Reinforcing rods and attachment devices can be added when necessary. Because of is low shrinkage in curing, it can be produced using molds taken directly from the building. Rather than being produced as standard components, FRP is custom fabricated for individual applications. PROPERTIES • Isotropic • Lighter weight than masonry, similar to sheet metal • More thermally driven expansion than masonry or metals • No load bearing capacity, so underlying framework must be used to accommodate any loads • High strength to weight ratio • Flammable • Not vapor-permeable • Can be produced in larger sections efficiently reproducing repetitive elements or features that were originally made up of small individual units • May be difficult to match false joints in multi- unit assemblies to actual joints that need to accommodate movement • Color can be incorporated into the surface gel-coat, or the surface may be coated 19    Page 33 Figure 20. Cement board was used to replace a non-historic infill and mimics the configuration of a typical vehicular door of the period. Photos: Historic Augusta. Fiber Cement MATERIAL : Fiber cement products are made from fiber, sand that is ground to a powder, cement, and proprietary additives to reduce moisture absorption. The fiber used in roof products is glass fiber alone, whereas siding and trim board products are primarily wood fiber. The material is formed with a smooth or textured surface, cut to standard sizes of panels, boards, or shingles, and cured in an autoclave. Roofing material has integral color, but board and siding products are produced with a primer, if not fully factory finished. Most siding and trim boards are embossed with a wood grain on one surface and are smooth on the other, the smooth side being the appropriate surface to imitate planed wood. PROPERTIES: • Products are minimally orthotropic • Heavier and more brittle than wood, limiting available lengths • Very little thermal- and no moisture-driven movement • Low water absorption, but not recommended for ground or roof contact • Class A flame spread • Resists insect damage • Available in limited thicknesses and widths • Not machinable, but may be cut with special carbide blades; cutting requires dust collection and personal protective equipment • Cut edges require sealing • Available unfinished, primed, or prefinished, and must be painted (with latex paint) • 15-year limited warranty typical 20    Page 34 Mineral / Polymer Composite MATERIAL : Calcium carbonate or fly ash are mineral ingredients held in a matrix of various polymers to produce materials formed or molded into a number of building products. Additives found in some of the roof- ing products include pigments and UV stabilizers. Some use a substantial portion of recycled material. Different combinations yield products with different properties, each formulated for a specific building component. When the material is fly ash with some glass fibers bound in a matrix of polyurethane, it is identified as polyash. Siding, trim, bead board, and deck products are primed or prefinished, whereas roof products have integral color. PROPERTIES: Fly ash (siding and trim) • Isotropic • Heavier and more brittle than wood, and lacking structural capacity • Little thermal or moisture-driven movement • Sufficiently low water absorption to permit ground contact • Class C flame spread • Resists insect damage • Available in limited thicknesses and widths • Machinable with carbide tools blades; requires dust collection • Cut edges do not require sealing Figure 21. A mineral polymer composite siding was available in the profile very similar to the historic siding. The replacement siding was used where the original material was almost completely missing beneath a more modern covering. Areas where the original wood was largely intact were replaced with matching wood to sustain more of the material integrity of the building. Photo: Belk Architecture. • Must be painted • 30-year limited warranty typical Calcium carbonate or recycled rubber (roofing) • Isotropic • More thermally-driven movement than slate or wood • Little to no moisture absorption • As shingles: lighter and more flexible than slate • As tongue-and-groove decking: heavier and harder than wood • Not vulnerable to insect damage • Available in limited dimensions • As shingles: Class 4 impact resistance, and flame spread ratings ranging from Class A to Class C depending on the specific product • As shingles: integral color, that may be subject to fading • As tongue-and-groove decking: prefinished with non-renewable finish, and can be cut with woodworking tools • 50-year limited warranties on roofing products typical 21    Page 35 Cellulose Fiber / Polymer Composite MATERIAL : Wood strands or fibers are coated with resin for moisture resistance and zinc-borate for insect and fungal-decay resistance, then consolidated under heated pressure. Solid composite core boards are cut from sheets of material, then factory-primed or finished. Resulting siding and trim board products can be referred to as engineered wood, fiber board, or hardboard. Products may be embossed with a wood grain or have a smooth finish, the smooth side being the appropriate surface to imitate planed wood. Siding, trim, and tongue-and-grove decking with a slightly different properties are produced by extruding polyvinyl chloride (PVC) combined with non-wood cellulose. Roofing shingles are molded from fine wood fibers, color additives, and UV stabilizers bound with polypropylene or polyethylene (thermoplastics). Figure 22. A porch was reconstructed using posts fabricated on site from a smooth-surface cellulose/polymer composite material. Though the face of the posts are painted, the lack of paint on the bottom at the cut ends is not consistent with manufacturers’ recommendations. This treatment will allow moisture to be absorbed, shortening the life of the new replacement feature. Photo: John Sandor, NPS. PROPERTIES: Predominantly Cellulose (siding, trim and decking) • Minimal thermal movement • Resistant to moisture-driven movement • Lighter and more flexible than solid wood, but lacks structural capacity • Rice hull cellulose: can span typical floor-framing spacing as decking • Low water absorption (for wood, no ground or roof contact) • Class A or Class C flame spread • Resists insect damage • Available in limited dimensions • Machinable with woodworking tools • Wood cellulose: Cut edges must be sealed and may need additional surface prep for finish; must be painted if unfinished or primed, also available prefinished • Rice hull cellulose: Accepts stain/paint, but no finish required • 30–50 year limited warranty, depending on manufacturer Predominantly Polymer (roofing) • Minimal thermal movement • Little to no moisture absorption • Lighter and more flexible than slate • Class 4 impact-resistance • Class A flame spread • Available in limited shingle size • 50-year limited warranty typical 22    Page 36 Figure 23. 3-D printing using various polymers is occasionally used to replicate missing metal or wood features. This new application is continually being refined, but the application can be successful when a painted, lightweight feature needs to be replicated. Photo: NPS. Non-composite Polymers MATERIALS: The main two polymer materials used without significant other components are polyurethane and polyvinyl chloride (PVC). Polyurethane millwork is constructed of urethane foam created by mixing isocya- nate and resin. The polyurethane mixture is kept under pressure in a mold as it expands to any desired shape. These molded products have a closed-cell, foamed core with a denser surface skin. Polyurethane products can have exterior applications but are more often used for interior features. Polyvinyl chloride (PVC) in a solid extruded form is another polymer that can have archi- tectural application as tongue-and-groove decking. Vari- ous polymers formed using 3-D printing are also being explored as replacements for painted metal or wood ornamental features. PROPERTIES: Each of the two groupings has distinct physical properties Urethane Foam (moldings and decorative elements) • Lightweight and flexible, but lacking structural capacity • More thermally-driven movement than wood or stone, but less than cellular PVC • Does not absorb water • Flammable • Resists insect damage • Can be cut with standard woodworking tools • Adhesive and mechanical fasteners both recommended for installation • Supplied primed and must be painted (latex paint) • Lifetime limited warranty typical Solid PVC (flooring) • Isotropic • Heavier and less flexible that wood • Minimal thermal movement • Does not absorb water • Strength to span typical floor-framing spacing • Impact-resistance greater than wood • Class A flame spread • No insect susceptibility • Good paint adhesion, but also available prefinished • 20-year warranty typical 23    Page 37 Cellular Polyvinyl Chloride (PVC) MATERIAL : Varying amounts of calcium carbonate and a foaming agent are added to melted PVC before passing through an injection die and then a calibrator to produce the shape and size of the finished product. Cellular PVC is produced as sheets, boards, and mold- ings. Differences in the specifics of the equipment and the rate of cooling create two varieties of product, with distinct properties. One is known as free-foam, having a fairly consistent structure throughout its section, and the other is identified as Celuka, having a skin that is denser than its core. This primarily affects the ease with which the product can be milled and shaped. The material is white and needs no applied finish. When produced for decking the material has a colored and textured wear layer over the PVC core. PROPERTIES • Isotropic • Lighter and more flexible than wood • Less strong than wood (in tension and shear), but can span typical floor- framing spacing as decking • More impact-resistance than wood • Negligible water absorption; no moisture-driven movement, unlike wood • Subject to thermal expansion and contraction significantly greater than wood, though the thermal movement is less for the same dimension than the cross-grain moisture-driven movement of wood • For longer pieces, thermal movement requires manufacturer’s specifications to be followed for attachment, and inclusion of expansion joints when installed at low temperature (joints should be glued) • Class A flame spread • Resists insect damage • Machinable with woodworking tools, though cut edges may need additional surface prep for finish • Good paint adhesion; if painted, high light reflectance (HLV) is recommended to minimize heat driven expansion • 25–30-year limited warranty, depending on manufacturer Figure 24. Cellular PVC when painted can be used to replace deteriorated wood features. This beadboard set in a wood frame was not historically designed to shed water eectively and had deteriorated. Cellular PVC was able to match the appearance of the wood details, while its properties were well matched to the shady location, painted finish, and limited size and configuration within the overall assembly; thus, it should provide a long-lasting solution for this application. Photo: Jennifer Balson Alvarez, NPS. Acknowledgements John Sandor, Architectural Historian, David Trayte, Historical Architect, and Amy Elizabeth Uebel, Architectural Historian, Technical Preservation Services, National Park Service, revised Preservation Brief 16: The Use of Substitute Materials on Historic Building Exteriors, originally written by Sharon C. Park, FAIA, FAPT, and published in 1988. The revised Brief contains expanded and updated information as well as new color photographs describing the general issues and application of substitute materials on historic buildings. The authors wish to thank the following: Peyton Hall, FAIA, Principal Architect Emeritus, Historic Resources Group, Mary Jablonski, President, Jablonski Building Conservation, Inc., Thomas Jester, FAIA, FAPT, LEED AP, Principal, Quinn Evans, Sharon Park, FAIA, FAPT, Associate Director Emerita, Smithsonian Institution, Debra Slaton, Principal, Wiss, Janney, Elstner Associates, Inc., for their guidance and review of this revision; and to Brian Goeken, Chief of Technical Preservation Services, National Park Service, and Jo Ellen Hensley, Elizabeth Tune, and Jennifer Oeschger, Technical Preservation Services, National Park Service, for their help in the editing of the publication. Illustrations not specifically credited are from National Park Service files. Front cover image: Installation of a new roof feature on a ca.1895 commercial building. The dome was constructed of fiber-reinforced polymer to replicate the missing original feature in Aurora, Illinois, 2023. Photo: Kelsey Cozens/JH Real Estate Partners LLC. This publication has been prepared pursuant to the National Historic Preservation Act of 1966, as amended, which directs the Secretary of the Interior to develop and make available information concerning historic properties. This publication is available from the Technical Preservation Services website at http://www.nps.gov/tps/ or hard copies may be purchased from the Government Printing Offices at the U.S. Government Bookstore at https://bookstore.gpo.gov/. Comments about this publication should be addressed to Technical Preservation Services, National Park Service, 1849 C Street, NW, Mail Stop 7243, Washington, DC 20240, or by email to NPS_TPS@nps.gov. This publication is not copyrighted and can be reproduced without penalty. Normal procedures for credit to the authors and the National Park Service are appreciated. The photographs used in this publication may not be used to illustrate other publications without permission of the owners. October 2023 24    Page 38 HPC RESOLUTION NO. 2025-001 A RESOLUTION OF THE HISTORIC PRESERVATION COMMISSION OF THE CITY OF RANCHO CUCAMONGA, CALIFORNIA, APPROVING CERTIFICATE OF APPROPRIATENESS DRC2025-00040, A REQUEST TO REHABILITATE THE FRONT PORCH OF THE CHAFFEY-ISLE HOUSE BY REPLACING THE WOOD FLOORING WITH COMPOSITE DECKING WITHIN THE VERY LOW (VL) RESIDENTIAL ZONE, LOCATED AT 7086 ETIWANDA AVENUE, AND MAKING FINDINGS IN SUPPORT THEREOF – APN: 1089-071-26. A.Recitals. 1. The applicant, City of Rancho Cucamonga and Etiwanda Historical Society, filed an application for Certificate of Appropriateness DRC2025-00040, as described in the title of this Resolution. Hereinafter in this Resolution, the subject Certificate of Appropriateness request is referred to as "the application." 2.On the 12th day of March 2025, the Historic Preservation Commission of the City of Rancho Cucamonga conducted a duly noticed public hearing on the application and concluded said hearing on that date. 3.All legal prerequisites prior to the adoption of this Resolution have occurred. B.Resolution. NOW, THEREFORE, it is hereby found, determined, and resolved by the Historic Preservation Commission of the City of Rancho Cucamonga as follows: 1.This Commission hereby specifically finds that all the facts set forth in the Recitals, Part A, of this Resolution are true and correct. 2.Based upon the substantial evidence presented to this Commission during the above- referenced public hearing on March 12, 2025, including written and oral staff reports, together with public testimony, this Commission hereby specifically finds as follows: a.The project site is located at 7086 Etiwanda Avenue, east of Etiwanda Avenue and north of Baseline Road and contains the Chaffey-Isle House, which is a historic landmark owned by the City of Rancho Cucamonga and occupied by the Etiwanda Historical Society; and b. The existing land use, General Plan designation, and Zones for the project site and adjacent properties are as follows: Land Use General Plan Zoning Site Historic Property Traditional Neighborhood Very Low (VL) Residential North Historic Property Traditional Neighborhood Very Low (VL) Residential West Single-Family Residence Traditional Neighborhood Very Low (VL) Residential South Community Trail General Open Space and Facilities Parks (P) Exhibit C   Page 39 HISTORIC PRESERVATION COMMISSION RESOLUTION NO. 2025-001 DRC2025-00040 – CITY OF RANCHO CUCAMONGA/ETIWANDA HISTORICAL SOCIETY March 12, 2025 Page 2 East Historic Property Rural Open Space Very Low (VL) Residential 3. Based upon the substantial evidence presented to this Commission during the above- referenced public hearing and upon the specific findings of facts set forth in paragraphs 1 and 2 above, this Commission hereby finds and concludes as follows: a. The proposed replacement of the deteriorated wood porch decking with composite decking will not result in a substantial adverse change to the historic resource within the meaning of the California Environmental Quality Act (CEQA). As stated in the staff report, the project is exempt from CEQA requirements. The composite material has been selected to closely match the original wood in appearance, texture, and color, ensuring the preservation of the porch’s historic character. Furthermore, the deterioration of the existing wood decking necessitates its replacement to maintain the structure’s integrity. As such, the project does not diminish the historical significance of the property; and b. The project is consistent with the purposes of the Historic Preservation Commission, and more specifically Development Code Sections 17.18.030 (Maintenance of Historic Resources) and 17.18.040 (Certificate of Appropriateness). The project aligns with the intent of these regulations by maintaining the architectural integrity of the historic structure. The replacement decking will preserve the visual and structural character of the porch while enhancing durability and reducing the need for frequent and costly repairs. Additionally, the project ensures the continued use and longevity of the historic resource, supporting the broader goals of historic preservation within the district; and c. The project is consistent with the Secretary of the Interior Standards for the Treatment of Historic Properties by complying with the applicable Standards for Rehabilitation. Standard 2 states, “the historic character of a property shall be retained and preserved. The removal of distinctive materials or alteration of features, spaces, and spatial relationships that characterize a property will be avoided.” The applicant proposes to install a composite material that closely mimics the appearance of traditional wood while maintaining the historic character of the porch. All other elements of the existing porch, including the turned wood columns, as well as all other character-defining features of the existing structure, such as the steep-pitched shingled mansard roof and unelaborated dormers and windows, shall remain unchanged. Standard 5 states, “distinctive materials, features, finishes, and construction techniques or example of craftsmanship that characterize a property shall be preserved.” The new composite material will closely match the original wood material in appearance, color, and dimension. The applicant selected to use the “Basics” line from the “Trex Enhance” composite decking product, which features a wood-like grain pattern. The character-defining elements of the porch, such as the balustrade, turned porch posts, and wooden skirting, are to remain fully preserved. Standard 6 states, “deteriorated historic features shall be repaired rather than replaced. Where the severity of deterioration requires replacement of a distinctive feature, the new feature shall match the old in design, color, texture, and where possible, materials. Replacement of missing features shall be substantiated by documentary and physical evidence.” While the decking of the existing porch may not be considered a distinctive feature of this architectural style, in an abundance of caution, the applicant has documented the advanced deterioration of the wood decking and proposed a composite alternative that closely matches the original in design, color, and texture while offering improved durability; and 4. The Planning Department staff determined that the project is categorically exempt    Page 40 HISTORIC PRESERVATION COMMISSION RESOLUTION NO. 2025-001 DRC2025-00040 – CITY OF RANCHO CUCAMONGA/ETIWANDA HISTORICAL SOCIETY March 12, 2025 Page 3 from the requirements of the California Environmental Quality Act (CEQA) and the City’s CEQA Guidelines. The project qualifies as a Class 1 exemption under State CEQA Guidelines Section 15301 – Existing Facilities, which consists of the operation, repair, maintenance, permitting, leasing, licensing, or minor alteration of existing public or private structures, involving negligible or no expansion existing or former use. Specifically, this includes the restoration or rehabilitation of deteriorated or damaged structures and facilities to meet current standards of public health and safety. Additionally, the project qualifies as a Class 31 exemption under State CEQA Guidelines Section 15331 – Historical Resource Restoration/Rehabilitation. The project scope is to rehabilitate the porch of a historic property by replacing all 620 square feet of the wood porch decking to a substitute composite material, “Trex Enhance” composite decking. There is no substantial evidence that the project will have a significant effect on the environment. 5. Based upon the findings and conclusions set forth in paragraphs 1, 2, 3, and 4 above, this Commission hereby approves the application subject to each condition set forth in the attached Conditions of Approval incorporated herein by this reference. 6. The Secretary to this Commission shall certify to the adoption of this Resolution. APPROVED AND ADOPTED THIS 12TH DAY OF MARCH 2025. HISTORIC PRESERVATION COMMISSION OF THE CITY OF RANCHO CUCAMONGA BY: Tony Morales, Chairman ATTEST: Jennifer Nakamura, Secretary I, Jennifer Nakamura, Secretary of the Historic Preservation Commission of the City of Rancho Cucamonga, do hereby certify that the foregoing Resolution was duly and regularly introduced, passed, and adopted by the Historic Preservation Commission of the City of Rancho Cucamonga, at a regular meeting of the Historic Preservation Commission held on the 12th day of March 2025, by the following vote-to-wit: AYES: COMMISSIONERS: NOES: COMMISSIONERS: ABSENT: COMMISSIONERS: ABSTAIN: COMMISSIONERS:    Page 41 Conditions of Approval Community Development Department Project #: DRC2025-00040 Project Name: Chaffey-Isle House Porch Location: 7086 ETIWANDA AVE - 108907126-0000 Project Type: Certificate of Appropriateness ALL OF THE FOLLOWING CONDITIONS APPLY TO YOUR PROJECT: Planning Department Please be advised of the following Special Conditions The color, material, and texture of the composite decking shall match the existing wood panels to the greatest extent possible or otherwise use comparable components. The final color shall be submitted to the Planning Department for approval by the Planning Director prior to initiating any work. All work must match the description of "Option #1: Trex Enhance Basics," as written in the estimate provided by Raymond Keith Pfau Construction dated 01/27/2025, or better. 1. Standard Conditions of Approval The applicant shall sign the Statement of Agreement and Acceptance of Conditions of Approval provided by the Planning Department. The signed Statement of Agreement and Acceptance of Conditions of Approval shall be returned to the Planning Department prior to the submittal of grading/construction plans for plan check, request for a business license, and/or commencement of the approved activity. 2. www.CityofRC.us Printed: 3/6/2025    Page 42 Project #: DRC2025-00040 Project Name: Chaffey-Isle House Porch Location: 7086 ETIWANDA AVE - 108907126-0000 Project Type: Certificate of Appropriateness ALL OF THE FOLLOWING CONDITIONS APPLY TO YOUR PROJECT: Planning Department Standard Conditions of Approval The applicant shall indemnify, protect, defend, and hold harmless, the City, and/or any of its officials , officers, employees, agents, departments, agencies, those City agents serving as independent contractors in the role of City officials and instrumentalities thereof (collectively “Indemnitees”), from any and all claims, demands, lawsuits, writs of mandamus, and other actions and proceedings (whether legal, equitable, declaratory, administrative or adjudicatory in nature ), and alternative dispute resolutions procedures (including, but not limited to, arbitrations, mediations, and other such procedures ) (collectively “Actions”), brought against the City, and/or any of its officials, officers, employees, agents, departments, agencies, and instrumentalities thereof, that challenge, attack, or seek to modify, set aside, void, or annul, the action of, or any permit or approval issued by, the City and /or any of its officials, officers, employees, agents, departments, agencies, and instrumentalities thereof (including actions approved by the voters of the City ), for or concerning the project, whether such actions are brought under the California Environmental Quality Act (CEQA), State Planning and Zoning Law, the Subdivisions Map Act, Code of Civil Procedure Section 1085 or 1094.5, or any other state, federal, or local statute, law, ordinance, rule, regulation, or any decision of a competent jurisdiction. This indemnification provision expressly includes losses, judgments, costs, and expenses (including, without limitation, attorneys’ fees or court costs) in any manner arising out of or incident to this approval, the Planning Director’s actions, the Planning Commission’s actions, and/or the City Council’s actions , related entitlements, or the City’s environmental review thereof. The Applicant shall pay and satisfy any judgment, award or decree that may be rendered against City or the other Indemnitees in any such suit , action, or other legal proceeding. It is expressly agreed that the City shall have the right to approve , which approval will not be unreasonably withheld, the legal counsel providing the City’s defense, and that the applicant shall reimburse City for any costs and expenses directly and necessarily incurred by the City in the course of the defense. City shall promptly notify the applicant of any Action brought and City shall cooperate with applicant in the defense of the Action. In the event such a legal action is filed challenging the City’s determinations herein or the issuance of the approval, the City shall estimate its expenses for the litigation. The Applicant shall deposit said amount with the City or, at the discretion of the City, enter into an agreement with the City to pay such expenses as they become due. 3. Copies of the signed Planning Commission Resolution of Approval or Approval Letter, Conditions of Approval, and all environmental mitigations shall be included on the plans (full size). The sheet (s) are for information only to all parties involved in the construction /grading activities and are not required to be wet sealed/stamped by a licensed Engineer/Architect. 4. The applicant shall be required to pay California Department of Fish and Wildlife Notice of Exemption fee in the amount of $50.00. All checks are to be made payable to the Clerk of the Board Supervisors and submitted to the Planning Commission Secretary prior to public hearing or within 5 days of the date of project approval. 5. Any approval shall expire if Building Permits are not issued or approved use has not commenced within 2 years from the date of approval or a time extension has been granted. 6. Approval of this request shall not waive compliance with all sections of the Development Code, all other applicable City Ordinances, and applicable Community, Specific Plans and /or Master Plans in effect at the time of Building Permit issuance. 7. www.CityofRC.us Page 2 of 3Printed: 3/6/2025    Page 43 Project #: DRC2025-00040 Project Name: Chaffey-Isle House Porch Location: 7086 ETIWANDA AVE - 108907126-0000 Project Type: Certificate of Appropriateness ALL OF THE FOLLOWING CONDITIONS APPLY TO YOUR PROJECT: Planning Department Standard Conditions of Approval The site shall be developed and maintained in accordance with the approved plans, including site plans , floor plans, elevations, exterior materials and colors on file with the Planning Department, the conditions contained herein, and all other applicable Development Code regulations. 8. The project contains a designated Historical Landmark. The site shall be developed and maintained in accordance with Certificate of Appropriateness DRC 2025-00040. Any further modifications to the site including, but not limited to, exterior alterations and /or interior alterations which affect the exterior of the buildings or structures, removal of landmark trees, demolition, relocation, reconstruction of buildings or structures, or changes to the site, shall require a modification to the Certificate of Appropriateness subject to Historic Preservation Commission review and approval. 9. www.CityofRC.us Page 3 of 3Printed: 3/6/2025    Page 44 DATE:March 12, 2025 TO:Chairman and Members of the Planning Commission FROM:Jennifer Nakamura, CNU-A, Planning Director INITIATED BY:Aracely Estrada, Management Analyst I SUBJECT:Consideration to Receive and File the 2024 General Plan Annual Progress Report and the Housing Element Annual Progress Report RECOMMENDATION: Staff recommends that the Planning Commission receive and file the 2024 General Plan Annual Progress Report and Housing Element Annual Progress Report. BACKGROUND: A General Plan is a city’s blueprint or constitution, for future development. It documents the city’s long-range vision and establishes clear goals, objectives, and actions to guide the community through the next 10 to 20 years of change. A city must update its general plan periodically to keep up with changing needs and conditions of the city and region. It should also be updated to reflect new local, state and federal laws. State law requires each city and county to adopt a General Plan that address several topics, typically referred to as “elements.” This includes the adoption of a Housing Element. The Housing Element is an important planning policy document that is used to identify the City’s projected housing needs and establish policies that support development of all housing types, including affordable housing. The Housing Element is subject to detailed statutory requirements and mandatory review by the California Department of Housing and Community Development (HCD). The Housing Element is currently in its 6th Cycle, which covers an 8-year planning period from October 2021 through October 2029. The 6th Cycle Housing Element was adopted by the City Council in October 2021 and certified by HCD in August 2022. California Government Code Section 65400 requires that each city and county prepare an Annual Progress Report (APR) to report on the status and progress of the General Plan’s implementation and separately, the Housing Element. Copies of both the General Plan and the Housing Element APRs must be provided to the California Governor’s Office of Land Use and Climate Innovation (LCI), formally Governor’s Office of Planning and Research (OPR), and HCD by April 1 of each year. Section 65400 of the Government Code also requires that the annual report be considered at a public meeting before the legislative body allowing for public comment, but not necessarily held as a public hearing. The General Plan APR is separate from the Housing Element APR in that the General Plan APR provides local legislative bodies and the public an update on the progress of implementing the General Plan for their city or county, while the Housing Element APR demonstrates the City’s progress in meeting its projected housing needs. Unlike the Housing Element APR, the General Plan APR does not have a standardized format and the guidance provided by LCI allows for flexibility, which may need to vary based on a jurisdiction’s individual circumstances.    Page 45 Page 2 of 2 2 7 4 4 ANALYSIS: The City Council adopted its current General Plan on December 15, 2021. The updated General Plan, also referred to as Plan RC, lays out a series of strategies to chart a path towards a 21st century world-class community that is grounded in the foundational core values identified by the Rancho Cucamonga community: Health, Equity and Stewardship. The vision of Plan RC is to create a city for people – a city of great neighborhoods, natural open spaces and parks, thriving commercial and industrial areas, and walkable and active centers and districts, all connected by safe and comfortable streets. The attached General Plan APR summarizes a variety of measures and activities undertaken by the City in 2024 that advance the goals and policies of the General Plan. Embracing the opportunity for flexibility in the APR’s format, Rancho Cucamonga’s report has been developed in an easy-to-read format that allows it to also serve as a report card to the residents of Rancho Cucamonga on the city’s progress in implementing Plan RC. Highlights of the APR include measures taken to implement the General Plan and the corresponding General Plan policies it supports as well as highlights of development projects that were active in 2024. The General Plan APR also includes data from the Housing Element APR such as the number of applications submitted and the number of housing units entitled, permitted, and constructed. While the Housing Element APR is submitted to LCI and HCD in a large excel file that includes detailed data as required by HCD, the General Plan APR summarizes key points of the Housing Element APR. The General Plan APR and Housing Element APR will be presented to City Council on the March 19, 2024, meeting and will be submitted to LCI and HCD by the April 1st deadline. FISCAL IMPACT: None. COUNCIL MISSION / VISION / VALUE(S) ADDRESSED: As part of the implementation of the General Plan, this item supports the City Council’s Vision of creating an equitable, sustainable, and vibrant city, rich in opportunity for all to thrive by building on our foundation and success as a world class community. EXHIBITS: Exhibit A – Draft 2024 General Plan Annual Progress Report    Page 46 Exhibit A DRAFT    Page 47    Page 48    Page 49    Page 50    Page 51    Page 52    Page 53    Page 54    Page 55    Page 56    Page 57    Page 58    Page 59    Page 60    Page 61    Page 62    Page 63    Page 64    Page 65    Page 66    Page 67    Page 68    Page 69    Page 70    Page 71    Page 72    Page 73    Page 74    Page 75    Page 76    Page 77    Page 78    Page 79    Page 80    Page 81    Page 82    Page 83    Page 84    Page 85    Page 86    Page 87    Page 88    Page 89    Page 90    Page 91    Page 92    Page 93    Page 94    Page 95    Page 96    Page 97    Page 98    Page 99    Page 100    Page 101    Page 102    Page 103    Page 104    Page 105    Page 106    Page 107    Page 108    Page 109    Page 110    Page 111