Roofs

Maintenance and Repair

• Clean gutters and downspouts and replace deteriorated flashing. Replacement flashing should match the material, color, profile, and patina of the existing material. Roof sheathing should also be checked for indications of moisture due to leaks or condensation.
• Ensure historic and/or original drainage features and systems that divert rainwater from surfaces (such as roof overhangs, gutters, and downspouts) are intact and functioning properly. If beyond repair, the drainage feature(s) may be replaced with an in-kind product that matches the scale, material, color, and profile.
• Temporary waterproof membranes, roll roofing, plywood, or tarpaulin can be used to protect a leaking roof until it can be repaired, but should not be used more than 4 months.
• When necessary, deteriorated materials may be replaced if the replacement duplicates the form and detailing as closely as possible. Only the portion that has deteriorated should be replaced. 
  • For example, an entire slate roof should not be replaced if only a small portion can be repaired with replacement tiles.

• If using the same kind of material is not feasible on a whole roof replacement, a compatible substitute material may be considered if the appearance, size, scale, and texture are similar.
  • For example, a wood shingle roof may be replaced with a neutral-colored asphalt shingle or synthetic product that matches the appearance of the wood shingles. Low pitched roofs and roofs greater than a story are more ideal for these modifications because the visual impact is reduced.

• Replacement of asphalt shingle roofs whether 3 tab, rolled, or architectural shingle is allowed with any of these three types of asphalt shingle products such that the profile and design of the new shingle product matches the existing or a documented original appearance.

Rooftop Alterations

• Preserve the form and features of the original historic roof.
  • Avoid altering the length and depth of original overhangs which are characteristic of many architectural styles such as the bungalow.
  • Preserve roof features such as original dormers, parapets, chimneys, towers, turrets, crests, etc.
  • Maintain the original roof shape and form.
• Minimize the visual impacts of skylights, dormers, elevator or stair towers, decks or terraces, skylights, or other rooftop alterations.
  • Locate new dormers or skylights below the ridgeline of the roof, preferably on the rear or a side-facing slope when possible. Dormers or skylights installed on the side facing slope shall be set back from the edge of the roofline by at least 2 feet to minimize its visibility.
  •  New skylights should have a low profile, and not be a bubble skylight or other form that is not flat.
  • Dormers should be designed to match the prevailing style of dormers in the area. For example, a shed dormer would be inappropriate when most dormers or rooflines are gable in shape.
• The addition of a cool or green roof can be an efficient energy savings measure for historic buildings when properly designed.
  • Ensure the additional landscaping, railings, or other furnishings are not visible from the public right-of-way and do not damage the roof structure.
  • Inspect the rooftop structure to ensure it has the capacity to carry the additional weight of the plantings and soil necessary for the roof.