Using Roofing Granules with Roof Coatings
Roofing granules may be embedded into roof coating systems to add impact and abrasion resistance. It also helps create a non-slip surface for safety. Application rates can vary. Expect to use about 40 lbs. of #11 3M roofing granules for every 100 SF of application area to cover the roof completely. If a non-slip surface is the only requirement, 10-20 lbs./100 SF should suffice. You are merely adding grit to the surface and not using the granules as a surfacing layer. Lexis recommends the granules be broadcast on the third (adhesive) coat after the base coat and finish coat has been allowed to dry for at least 3 to 4 days. The granules should be spread evenly while the third coat is still wet. Do one section at a time. Once the coating is dry, you can use a blower to remove any remaining loose granules, recover them and use them on the rest of the roof. Granules may continue to release from the coating over time since it is just a surface layer. This behavior is similar to modified bitumen membranes. Granules can slowly penetrate the coating membrane if the surface is subjected to frequent foot traffic. If light maintenance traffic is expected in some areas, install 40” wide SeamStitch fabric between the first and second coats over walkways. Use walkpads over heavy maintenance areas.