So I've been trying to wrap my head around the purpose of a roof flashing for the wood stove. I know it is supposed to be for waterproofing but wouldn't just running the chimney pipe through the roof with proper combustible clearances and high temp silicone work? The flashing is more a first line of defence I suppose. Flashing plus storm collar will prevent most water from getting to the seam where the chimney pipe goes through the roof but won't it also trap water assuming the stove is not burning to evaporate it. Ive seen the rubber ones people talk about here and they seem like a good idea but do they hold up to the heat well enough? Just over thinking as usual
the "rubber" ones are actually high temp. silicone.
They woork very well. I would not want to have flat surfaces no matter what material gooped on and around the stove pipe attempting to keep the weather out.
The high temp silicone is also use to make molds for casting lead fishing weights and zinc too for other small items. Aluminum too but the silicone breaks down soon due to the 1200 degree temps.
Lead melts at about 620 and zinc at 790 or so and the high temp silicone resist those temps quite well.
Flashing is designed for shingle roofs. If you look at the vent pipes going through the roof on your house you'll see the upper shingle goes over the vent flashing and the lower shingle goes under the flash. This makes the flashing part of the shingle roof and keeps water rolling downhill as it should.
A bus roof has no shingles so just dropping flashing over the pipe won't seal out water. You'd have to seal the flashing to the roof.
As far as heat is concerned, using triple wall piping where the pipe goes through the roof will keep the outer wall of the pipe just warm to the touch so low temp sealants would work fine. Have a look at Henry 212 roof sealant instead of silicone sealants. It's a clear, heavy duty sealant and I've used it on all my caulked seams with great results.
Eric, Hey I just used Dektite High temp flashing rated at continuous temp of 437 degrees with max temp of 500 degrees. It is water proof and super easy to install. Just bolted down seal with Butyl-flex sealant and ran my Class A pipe through it. Here is what i Did.
Thanks guys! I think I'm going to use this and try to get my hands on an o ring to seal between flashing and chimney that way if it goes bad I can just pull the pipe out and replace the o ring. I'll also use a high temp silicone and metal storm collar. Any thoughts?