It’s not uncommon for some roofs to receive multiple coating systems during their lifespan. In this case study, we feature a silicone recoat with the Envir-O-Sil System on a 100,000 sq. ft. modified bitumen roof.


Representatives of a high school in the Mobile, Alabama area began to report numerous leaks in their building. To learn the extent of the problem, an American WeatherStar Approved Contractor was sent to evaluate the roof and was quickly able to identify the source of the leaks. They also discovered the roof had previously been coated with a silicone system about 10-12 years earlier.

Aside from a few small problem areas, the existing silicone top coat was found to be mostly intact. It was later determined that the leaks occurred because the seams were not properly addressed during the initial silicone system install. The contractor proposed that a silicone recoat with the Envir-O-Sil System from American WeatherStar was the best solution.


First, an adhesion test patch was performed to ensure the system would adhere to the existing membrane.

Next, the roof was pressure washed to remove any dirt, dust, debris, and loose coatings.

Next, Terminator 622—a thick waterproofing sealant that adheres especially well to silicone—was used for select problem areas of the roof in need of repair. All seams, fasteners, penetrations, and transitions were then coated with Silicone Brush-Grade 422.

Once the problem areas and flashing details were addressed, two coats of High-Solids Silicone 412 were then applied to the roof. This low VOC product forms a weather-resistant, rubber-like seal and provides the roof with excellent UV protection and weatherability.


While the main objective of this project was to stop leaks, proper treatment of the seams and other flashing details will ensure the long-term success and performance of this newly-installed system.

Once completed, the roof received an additional 10 years of warranty protecting it from any future leaking problems. For the school system, the Envir-O-Sil System was a much more cost-effective alternative to a full roof replacement.

Want to know if the Envir-O-Sil System is right for your roof? To learn more, schedule your free roof inspection with an American WeatherStar Approved Contractor today.

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