THERE AREN’T MANY TIMES SILICONE CAN’T BE USED, BUT THEY FALL IN THESE CATEGORIES
- Substrate unsafe, not structurally sound
- Substrate unsettled, such as coal tar pitch
- ubstrate damaged
Silicone roof coatings can adhere to almost any surface. They can restore almost any surface. They can perform in almost every situation. But, there are a few known situations in which they cannot. If your roof falls into one of these categories, we recommend that you steer clear of silicone.
The Roof is Unsafe
In these scenarios, we’re referring to a roof or building that is structurally unsound and is a hazard. It may be dangerous to anyone walking on the roof, and to those inside. Even if it is safe to walk on, this roof shouldn’t be restored until it is adequately prepared. While no one may get hurt while restoring the roof, in 10-15 years, it may have more issues.
Coal Tar Pitch
Coal tar pitch is a roof type that is constantly re-emulsifying. Every day when the temperature increases, the tar returns to its liquid form, resealing cracks and holes. This is a fantastic roofing system because it is self-healing, but when it is coated, the silicone will tear as the substrate moves beneath it. Any roofing system that is unsettled, intentionally or unintentionally, is not a candidate for a silicone roof coating.
The Substrate is Damaged
Different from an unsafe roof, a damaged substrate can still be completely safe while not performing well. One of the most common examples we see is when single-ply membranes wear out and the “scrim” is exposed. The scrim is essentially the backing of the single-ply membrane, almost like a webbing. This scrim is abrasive and corrosive and will eat right through any roof coatings applied to it. When you apply silicone over exposed scrim, you are asking for system failure.
Other systems that are failing to the point of becoming corrosive, developing gaps or holes too big for silicone to cover, or exposing the roof deck are not good fits for silicone without first being repaired. Once repaired, these roofs can be restored. Even after making repairs you can usually still save money.
While silicone roof coatings work in most scenarios, there is no such thing as a magic bullet. You will still find scenarios in which silicone doesn’t perform well and hopefully avoid these pitfalls. If you think your roof might be a candidate but aren’t sure, contact us today.