I used Flex Seal (White) to seal under a window. I sprayed it (1/2 can) along the entire bottom of the vinyl window and onto the stucco wall. I let it sit 24 hours then added the rest of the can, so this had at leasts 6 coats. At first it held up really good and was flexible. However, after soaking up the UV rays from the sun for 4 weeks, it has now changed its properties and turned brittle. There are now large cracks in the stuff and it chips away like paint. It’s good for a short duration in the shade, but gives up the ghost after the sun bakes the oils out of it. Do not depend on this stuff to fix your leaky problem. Do it correctly the first time and never worry about the leak again.
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