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| MiraVista by Owens Corning | Majestic Slate by EcoStar | FlexShake by US Century | Celadon Ceramic Slate by CertainTeed |
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Owners of older homes are often determined to keep original exterior features such as slate roofs. That is, until the see the price of replacing one of these roofs. Composition shingles are less expensive, but don't give the same historic look and architectural detail.
A new generation of slate look-alikes offer the best of both worlds -- the look and durability of slate at a lower cost with less weight.
The National Park Service's Historic Preservation briefs recommend repairing or replacing historic architectural material whenever possible. However, this bible of historic preservation, acknowledges that substitute materials that replicate the look of historic materials are being used more and more in preservation projects, and notes that in many cases the results are positive.
"(Substitute materials) can be cost-effective, can permit the accurate visual duplication of historic materials, and last a reasonable time. Growing evidence indicates that with proper planning, careful specifications and supervision, substitute materials can be used successfully in the process of restoring the visual appearance of historic resources," according to Preservation Brief # 16, The Use of Substitute Materials on Historic Building Exteriors.
CertainTeed, better known for its composition roofs, offers Celadon Ceramic Slate, a tile that combines the thickness, texture and color of natural slate with the fired-in strength and durability of ceramic tile. At 580 pounds per square, Celadon is among the heaviest of the substitute slate roofing materials, but its weight is still only about half that of natural slate.
EcoStar's Majestic Slate and EuroSlate are made from recycled post-industrial waste rubber and plastic, and weigh as little as 166 pounds per square, depending on application. The roofing material is derived from EcoStar's "starloy," a product that was developed for sea dock walkways 20 years ago. Majestic Slate is made from 100 percent recycled material and is intended exclusively for historic restoration, while EuroSlate is 60 percent recycled material, and is available in a standard rectangle shape as well as a scalloped edge.
Flex Shake tiles from US Century, are made of recycled steel reinforced rubber fastened heat welded pockets over the tiles to 2.5 mil high-density polyethylene panels. Every shake is hand-crafted and coated with natural ground slate to create subtle variations in color and texture. The inherent properties of slate make it naturally UV resistant, and inhibit the formation of unsightly salt deposits (efflorescence). The panels weigh 350 pounds per square.
MiraVista, from Owens Corning, looks like the real thing, but is made from from slate and clay reinforced with fiberglass and then bonded with resin. Weighing in at 450 pounds per square, MiraVista, like the other imitation slates costs much less than natural stone.
The Extension Service of Cornell University estimated roofing costs in 1997, with natural slate costs ranging from $320 to $1,200 per 100 square feet. A natural slate roof will last anywhere from 50 to 100 or more years, and can weigh as little as 600 or as much as 1,200 pounds pounds per square. A fiberglass shingle roof weighs 200 to 425 pounds per square, depending on the quality of shingle, and lasts 15 to 20 years. According to national mortgage broker Freddie Mac costs $130 to $175 per 100 square feet.
The new generation of synthetic slates fall somewhere between slate and fiberglass shingles in cost and weight. Imitation slate roofs can weigh as little as under 200 pounds per square to as much as 600 pounds per square. Manufacturers of synthetic slates estimate the materials life span at 40 to 60 years or more.
