What is roof coating?

Roof coating is a liquid-applied roofing membrane that seals the entire roof from leaks. The roof coating has elastic materials that let it stretch out while liquid and dry completely sealed to the existing roofing, forming a complete waterproofed barrier at the joints and around the flashing.

Typically installed by a roofing contractor, roof coatings are applied by brush, roller, or spray, with the spray application giving the best results. Prior to applying the roof coating, a thorough inspection is done for loose fasteners, gaps, cracks, or tears which must be repaired. Next, a thorough pressure washing with biodegradable detergent is necessary, and the roof must be allowed to dry completely. Primers often improve the bond between the existing roof structure and the roof coating. Sometimes priming might be optional, but the cost is so minimal that it most often is done.

The roof coating is generally applied in two to three layers, always allowing for adequate drying time in between for best waterproofing. Often, the roofing contractor will tint the base coat to ensure even coverage of the final coat.

Roof coating varies in thickness when dry from about 3 mils to more than 40 mils, and the roof coating becomes the new top layer of the entire system; it protects the structure from rain, hail, and other physical damage, as well as the impact of sunlight.  

In fact, often reflective roof coatings are used to extend the life of existing roof substrates by helping to lower the roof surface temperature and providing protection from the weather and sun, as well as keeping the protected structure cooler. Studies by roof coating company Lexis have shown that reflective coatings can also reduce air conditioning bills.