Preparation Decides the Result
Silicone adheres only to a clean, dry, sound surface. Dirt, mildew, oxidized membrane and residue from earlier coatings keep it from bonding, so cleaning and priming are most of the work. Some existing coatings and sealants are incompatible and must be removed or isolated.
Before recommending silicone, we pull a small adhesion test patch and record the result. We also check for moisture with an infrared survey and a few core cuts. If the roof passes, the scope is written with preparation steps, coverage rate and cure time, and the log carries the test results.
The log also notes air and surface temperature, dew point, wind and the twelve-hour forecast on the application day. Silicone that gets rained on before it cures can wash out or blister, so the crew starts only when the window is real and stops when it closes. The recorded conditions let the owner and the manufacturer see that the work was done within limits.