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rachel_lagiakos

Roof coating: silicone, urethane (aliphatic) or rubber formy flat roof

Rachel L
3 years ago

I'm in NYC and have a flat roof with a slight slope. I have some ponding in areas and those ponded areas have caused me grief below. The leaks mainly came after big snowstorms. We've patched what we believe to be the leaking spots with a new layer of roof paper (Firestone APP 160, which I think is modified bitumen), and taped/flashed all the seams. Now I'd like to give it a roof coating.

The roof has previously been coated with fibered aluminum. It seems to be what everyone uses here, though I read that a) it is not giving me any waterproofing protection b) it has poor longevity. The cracks I can see in the old coating support that maybe its not so great.

At the least, I want to upgrade to a better coating to waterproof my troublesome areas, then maybe use a moderately less expensive coating for the rest of the roof where there is no ponding and maybe less necessary to use the fanciest stuff.

What material should I go with: silicone, aliphatic urethane or rubber? And then is there a particular product you recommend? I am in NYC, so extreme cold winters and extreme hot summers. There is very little to no foot traffic on my roof. Roughly 1500 sq ft.

Will your recommendation be compatible with the modified bitumen tar paper, and will it be compatible to paint over the areas with the old fibered aluminum coating?

The roof is VERY old and I will consider replacing it entirely sooner than later. Hoping to get another few years if I can stretch it that far.

Thanks so much in advance!!!

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Comments (3)

  • res2architect
    3 years ago

    The ponding needs to be addressed. Perhaps install tapered insulation and a fully-adhered single-ply membrane.

    Rachel L thanked res2architect
  • PRO
    CoolAir Inc.
    2 years ago

    Silicone is best if you want to cover the ponding it also reduce the seepage and mold.

    Rachel L thanked CoolAir Inc.
  • Jessica Claire
    11 months ago

    What did you end up doing? I'm learning now. We have an old tar and gravel flat roof. We've had a few leaks patched since we purchased a few years ago...we'll be redoing the whole thing in the next year. Same weather in MN. Super hot and super cold. I hope everything went well!