• Alas & Bravo

Flat Roof Elastomeric Coatings


These are three different flat roof maintenance projects I worked on, where a white elastomeric coating was applied over the existing roof. The first image with skylights is an example of the coating application on a section of a residential home. The second is a coating over an apartment building flat roof. The final image is an example of the coating applied over a larger commercial building.


Regardless of the flat roof’s size, an elastomeric coating is an option available for owners looking to extend the lifetime of their existing flat roof. It is a liquid applied coating that dries into an elastic waterproof membrane. The white color of the coating also reflects the sun’s UV rays and keeps a building cooler.

Like any other roofing material, an experienced roofer must properly apply the coating to ensure the durability of the material. Other factors like the condition of the existing flat roof and the amount of weathering it has experienced play a part in the longevity of the coating.


To begin the roof maintenance, it is important for a roofer to remove and clear all debris from the roof. Depending on the condition of the roof, this can be done with any combination of removing debris off with a broom, brush, blow dryer, or using a power washer. If a power washer is used, it is important for the roof to be completely dry before any maintenance continues.

At any roof penetrations or critical areas I use an acrylic white mastic to seal the areas. If need be, at this stage in the process I may also reinforce other areas like corners, crickets, or drain areas. With my years of experience, I am familiar with what materials and tools work best to address any critical areas one may encounter on a flat roof.


Finally, the coating is evenly applied over the entire maintenance area using an airless spray equipment. Two commonly used options of elastomeric coating is acrylic and silicone.


An acrylic based coating is a more water based coating that functions best on areas that are not prone to standing water. If the coating experiences too much water saturation, the consistency and integrity of the coating will be compromised as the coating reverts back to a more fluid state and gets washed aways. Silicone is a more solid resin-based coating that makes it more resistant to water. This consistency and greater durability also makes the material a bit more costly.


Overall, flat roof coatings are a cost-effective option for owners who may not be ready to spend on a new roof. The coating application is a relatively quick maintenance process that can help protect the roof a while longer.