I have a fabricated triple wall stainless chimney that I need to reseal the joint between the exterior of the chimney and the roof flashing. It looks like it was previously sealed with black roofing cement. Is there a better choice? I'm thinking I want something somewhat flexible as the chimney should expand and contract some and the flashing sheet is pretty rigidly attached to the roof.
Seems to me that roofing goo (bearchit) is still probably the best bet imho, it flexes and seals well, I have not heard of better solutions yet. I have seen a few sealing jobs done with silicon but my experiences with it is that it has poor adherent qualities to metal over the spectrum of hot/cold/wet/dry, there may be products out there that work well but I have not heard of them yet. I have tried the non-bitumen roofing repair stuff to but it seems to dry out eventually and cracks etc. are hard to find sometimes which is frustrating so I've ended up going back to the tried and true. With a triple wall, just as a thought, there should not be a whole lot of expansion and contraction going on anyhow with the outside metal, I could be mistaken though and stand to be corrected. A good flashing job and a decent collar (the ones that attach to the chimney (you can seal that seam btw with all-weather silicon, that'd be the one that the tightening screw runs in, not the hole around the pipe) makes for a huge piece of mind as well.
My 0.02 fer the evening before I hit da hay (4:30AM wake up to send the dwarflette off on the water taxi for a 2 day class field trip, woo-hoo!)
