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"Synthetic" as it pertains to steep-slope roofing materials refers to manufactured
products that replicate asphalt shingles, concrete tile, clay tile, metal panels,
slate, wood shakes and wood shingles. Synthetic roof coverings contain recycled
plastic and/or rubber as a key ingredient. These products have been available since
There are some advantages to using synthetic roof coverings when compared to their
traditional counterparts. Synthetic slate, or "fake slate," for example, weighs
substantially less than natural slate. The reduction in weight allows synthetic
slate to be installed over conventional roof decks. Some synthetic products purport
to be hail-, mold- and algae-resistant. Several synthetic cedar shake and cedar
shingle manufacturers claim a labor savings, because fire-retardants or anti-algae
coatings do not have to be applied to the product.
Despite the benefits, there are some significant drawbacks. Synthetic roof coverings
are relatively new and there isn't a proven track record about their performance.
Most synthetic products are manufactured with dyes or coloring agents and it is
unknown whether these products will fade because of ultra-violet exposure and weathering.
It also is unknown whether these products will become more brittle or less flexible
over time. And most important, model building codes do not recognize any synthetic
roof coverings. You need to check with your local building department before installing
these products. Because of these reasons, caution should be exercised when using
synthetic roof covering products.
Currently, there are no ASTM International standards for synthetic steep-slope roof