The Secretary of the Interior's Standards:
The Standards require preservation of the building's historic character and significant features. Historic roofs should be repaired if possible. If replacement is necessary, in kind replacement is recommended, but compatible substitute materials can be used with the goal to match the historic material in design, color, texture, and other visual qualities.
Width of shingle tabs -- On typical three tab shingles (approximately 12 inches per shingle tab) the tabs are much wider than historic wood shingles, which were each about 4 to 6 inches wide.
Color -- Simulate weathered wood rather than new shingles (i.e., dark browns and grays rather than tan).
Visual texture -- Historic wood shingle roofs in Utah were typically sawn wood shingles, not split shake shingles. They were installed very evenly (aligned rows), with limited exposure (the distance between rows of shingles). The appearance was crisp and uniform, not shaggy or uneven.
Shingles with strong simulated shadows in the granule colors which results in a rough, pitted appearance.
Strongly variegated colors (i.e., strong mixtures of dark and light colors or shades).
Colors that are too light (e.g., tan, white, light green).
Wavy or deep color/texture used to simulate split shake shingles or slate.
Excessive flared form in the shingle tabs.
Uneven or sculpted bottom edges (either manufactured or installed) that emphasize tab width or edges, unless matching the historic shingles.
Historic conditions -- Examine remaining historic roofing materials, historic photos and wood shingle roofs. Attempt to replicate the historic appearance.
- Visibility and scale of roof -- Slightly more change may be possible on less visible roofs.
- Adjacent decorative elements -- The roof is often an important backdrop to, or actually part of, the overall decorative effort on an historic house.
Unacceptable: (unless matching the historic roofing material)
- GAF Sentinel and Landmark 50
- Certainteed Presidential Shake
- Metal shingles (e.g., aluminum shingles)
- Metal roofs (e.g., standing seam or corrugated panels)
- Concrete or other masonry roof tiles
- Slate or simulated slate products
Typically Unacceptable Shingles:
(See note below)
- Standard three tab shingles (with or without simulated shadows and color variations) – (types included are: Owens-Corning Prominence, Crestwood Shadow, Supreme, Classic, or Supreme Shadow; PABCO HO-25 or HM-30; etc.)
- Owens-Corning Oakridge Shadow and Atlas Pinnacle I or Pro 50 (very heavy shadow and color variation)
- GAF Timberline Grand, Country Mansion, Estate, Shaped Shingles (scalloped or sculpted edges)
- Elk Prestique Grande, Xtra Cool Colors, Gallery, Prestique Plus
- Certainteed Independence Shangle
Typically Acceptable Shingles:
(See note below)
- Owens-Corning Oakridge II
- TAMKO Heritage Premium 30
- GAF Timberline 30
- Elk Prestique High Definition, Raised Profile
- Certainteed Landmark 30, Woodscape
Marginally Acceptable Shingles: (all have light shadowing)
(See note below)
- Owens-Corning Oakridge Pro 4
- TAMKO Heritage Premium Shadowtone Series
- GAF Timberline 40 or Timberline Ultra (both with "Natural Shadow")
- Elk Prestique I (with " High Definition")
- Certainteed Landmark 40
Note: The use of proprietary names is not an endorsement of the product. Typically, equivalent products or materials are offered by other manufacturers. Approval of each rehabilitation is project-specific -- approval of a particular product on one project does not imply blanket approval of the product for subsequent projects. The State Historic Preservation Office and its staff assume no liability for any product recommendations. The building owner and their contractors are responsible for compliance with any and all building or safety codes and requirements.
See also: The National Park Service site on historic roofing.