[SubMareener]

I have used it on a flat roof that had cracks in asphalt. That was two years ago and still no leaks.

[Bethaneidh]

It works if folks use it correctly. Some problems can be averted by 1) degreasing the surface, and 2) using enough spray to cover gaps. However, it stinks like bloomin crazy, thus should be for outdoor use only, unless on an object you can sun for a couple of days. I take a chance on new stuff now n then out of my entertainment budget. ☺