A roof coating is a monolithic, fully adhered, fluid applied
roofing membrane. It has elastic properties that allows it to stretch and
return to their original shape without damage.
Typical roof coating dry film thickness vary from paint film
thickness to more than 40 dry mils. This means a roof coating actually becomes
the top layer of a composite roof membrane and underlying system. As such, the
roof coating is the topmost layer of protection for the membrane, receiving the
impact of sunlight (both infrared and ultraviolet (UV), rain, hail and physical
damage.
Benefits
Roof coatings are seamless and when installed correctly, can
solve roof leaks on almost any type of roof substrate.
There are exceptions: "professionals do not recommend
using cool coatings over existing shingles. This technique can cause moisture
problems and water damage because the coating can inhibit normal shingle drying
after rain or dew accumulation, allowing water to condense and collect under
the shingles."
Field-applied reflective roof coatings can extend the useful
life of nearly every roof substrate keeping a roof surface cool and
providing a level of protection from the sun and weather.
However, coating asphalt shingles and built-up composition
roofs requires more caution. The National Roofing Contractors Association’s director
of technical services has stated "The roofing industry is aware of a
number of issues that could have negative consequences for field application of
coatings over asphalt shingle roof systems. Anyone considering this type of
application should be aware of the concerns so they can weigh them against the
benefits claimed in coating product promotional materials."
Roof coatings can add 25 years to the service life of a roof
and reduce the amount of discarded roofing materials that end up in landfills.
The infrared image on the right shows "175°F" on the uncoated (black)
section of the modified bitumen roof. The coated (white) section is
"79°F". Field studies have shown that cool roof coatings can
lower rooftop temperatures and reduce air conditioning bills.
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