I have a double-flue chimney that has a leaky cap. It gets saturated
with water, then drips down into the wall cavity. I don't think it has
yet caused any real rot (hope not anyway) but I need to seal it from the
elements. I tried cleaning it with bleach/Jomax .. let it dry
thoroughly, then gave it 2 coats of RustOleum's epoxy-based concrete
paint. It held for about a year, but it is now coming off in big
flakes & pieces. What type of material is best to seal this porous
surface ?? ?? I thought about the paint they use on mobile home roofs,
but am looking for opinions. How about that rubber membrane they use
in shower-pans ?? ?? Just thinking out loud .. .. .. any
ideas/thoughts would be much appreciated.