We have a flat roof that sprung a leak last year, I'm just getting around to repairing it. What I found is that the existing elastomeric coating was not put in correctly - it is bubbling (meaning the elastomeric has air underneath it) to the point where I can peel it off, and when I do that, I find a lot of dirt between that layer and the underneath layer.

I want to apply Henry's tropicool (the silicone version) over the area instead of another coat of elastomeric, but I want to ensure I clean it properly. Where it bubbles, I pressure washed it to get most of it loose, then removed it by hand till I don't see anymore dirt. But still, there are a lot of loose pieces dangling around the edges where I peeled.

Before I roll on the Tropicool, is there anything else I can or should do to get it super clean/prepped? I don't want to have more bubbles/boils next year, although I can say for sure there will be close to no dirt between the roof and coating I am about to put on.

  • 2
    Is the old elastomeric material a sheet material that was applied or was it some type of paint/brush on material? Also what is the surface material that is under this elastomeric material? Answers to these will help for formulating a more comprehensive answer.
    – Michael Karas
    Commented Aug 10, 2020 at 0:09
  • @michael it was elastomeric in liquid form that you roll/paint on. Henry's is one example. Underneath is a foam roof but it looks like the previous coat of elastomeric is still intact
    – Greg
    Commented Aug 10, 2020 at 3:52


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