When having a contractor evaluate your roof or when doing the work yourself, there are many things to look for. One of the most often overlooked problems is determining what the product is that was used to patch or coat the roof previously. Silicone is often used to glob fasteners or even to coat the entire roof itself. Most products can be cleaned and applied over when dry. Silicone, on the other hand, must be completely removed as nothing will bond to it. Before applying any product over suspected silicone, you should apply a test patch to check for adhesion.
When a silicone repair fails, it must be completely removed, as well as the residue it leaves behind. That may mean grinding it off of a metal roof, or scraping it off of other substrates. Once that’s done, use a 100% rubber repair compound, such as Topps Polyprene®. That will get the job done right, the repair will be long-lasting and you won’t continue to experience call-backs.
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