Slate or Slate Substitute?

by Scott Brooks-Miller

What’s in a roof? Aside from being the most important component (along with the foundation) of a structure, a roof keeps the interior dry, warm, and habitable – take away the roof and the building fails. It is also a significant character-defining element. The roof with windows, doors, and façade all contribute to a building’s architectural significance. What do you do when your historic roof, whether slate, metal, or wood, reaches the end of its material life?
Today, historic homeowners are being sold on new roofing materials of slate- or wood-like in appearance that come with a lifetime warranty. Many manufacturers claim that these are maintenance-free alternatives to the original slate that cover many of Virginia’s historic homes.

We found that several manmade slate substitutes mimic the profile and depth of slate roof tile. They are made from recycled tires or feature a baked finish on a composite substrate. These alternative slates are often times 
Owners of this Winchester home are replacing the slate roof a few pieces at a time over a number of years.
just as expensive to buy and, though easier to install than quality slate, have a limited life span (24 years). The problem with composition shingles and other substitutes is that they rob or whittle away at the historic quality of a home or neighborhood. Real slate is still your best dollar value in terms of longevity and appearance.

A less expensive alternative to the high cost of total replacement of a slate and wooden roof is the replacement of pieces and components as they fail. It might take 25 years to piecemeal new slates or shingles. The bonus is that you get over the fear of heights and are afforded the opportunity to inspect your roof on an annual or semi-annual basis for cleaning and other repairs.

There is help for the homeowner with roof trouble whose property is listed in the state or national registers, or whose property has determined eligible for listing in the Virginia Historic Landmarks Register. You can take advantage of the Commonwealth’s generous investment tax credits to offset the cost of the rehabilitation work.

Have questions? Do not hesitate to contact your regional DHR office, or go to www2.cr.nps.gov and find Preservation Briefs 4, 16, 18, 29 and 30 for more information on the preservation of historic roofs.

 

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