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fireplace flues Post New Topic | Post Reply
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mark moyer
Posted: May 02, 2013 03:32 PM
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fireplace flues
old topic,,,revisited..how are you guys dealing with chimney flues?? |
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Mark Mouton
Posted: May 02, 2013 07:25 PM
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If your talking about sealing it at the roof line, I take a fiberglas batt without paper on it, wrap it tight around the pipe , shove it up to the hole, then bring the foam to the batt and glue it in place. If it's a 3" batt, we'll double wrap it. You can use duct tape around it bottom and top, zip ties, wire,etc. Do all this work down low then slide it up. (I'm talking about double wall pipe.) We put a thin piece of batt over can lights,an electrical box in the ceiling of a porch that were going to spray. Just spray over the fiberglas. Duct board would work good. The fiberglas would serve as a fireproof insulator for a short amount of extreme heat(like a short) We use the batts as a backer to seal the end of floor joists. It's already the right width. (I'm just ramblin now.), but the foam mixes good with those glass fibers and I believe it adds a little stability. Kind of like resin and glass on a boat or fiberglas septic tank. |
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SprayFoamSupply.com
Posted: May 03, 2013 06:39 AM
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We advise using rockwool insulation over fiberglass. It is tough to work with as it is so crumbly, but a better, safer end product. Wrap around and spray to it. You might have to use several pieces and foam them in one at a time. George |
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Mark Mouton
Posted: May 03, 2013 07:33 AM
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Rockwool batts? |
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mark moyer
Posted: May 03, 2013 08:39 AM
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look for roxul..good to 2150 degrees f.. mineral wool |
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Mark Mouton
Posted: May 04, 2013 09:50 AM
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Yeah, I looked up temps. Rockwool good for 2200 degrees, fiberglas good for 1000 degrees. 1000 degrees ain't nothing to turn your nose up at. Polyurethane good for 250 degrees. Ever tried to burn fiberglas in a wood fire. It won't go away. Aluminum cans will, fiberglas won't. I do agree though, Rockwool is the best. |
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mark moyer
Posted: May 04, 2013 12:50 PM
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looking for other acknowldegments of this practice,,,is this how its done???? or other acceptable practices... whats a hillbilly to do.. |
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John Shockney
Posted: May 04, 2013 10:52 PM
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3M makes a high temp duct wrap that is required for commercial kitchen exhaust hood ducting, it has an aluminum foil covering and the overlapping seams are taped with aluminum foil tape sealing the seams. Then stainless steel strapping is installed in case the tape fails. This is what is required by code over all welded exhaust duct in case of a grease fire. I use this same system between foam and the stainless steel flue pipe when there is going to be a wood fire, a chimney fire can reach temps over 3000degs burning through the SS pipe. I have used the Rockwool fire bats around masonry chimneys held in place with SS wire and glued in place with foam. But masonry can take more heat. Airpro |
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mark moyer
Posted: May 09, 2013 07:10 PM
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...once again,,as per usual,,, it is great to see all the responses from my seasoned comrades(?),,, |
