This past weekend I was up in the attic getting ready to lay down some insulation when I noticed that there was a pretty big gap between the chimney and the adjoining wall running pretty much the whole lenght of the chimney. I wasn't able to get close enough to measure it, but I'd say it's close to an inch pretty much the whole way.
Is this something I can seal with a can of the spray foam sealant or do I need something else?
TIA, tmo
That's supposed to be there. It keeps the chimney away things that burn, so that your chimney fire doesn't cook off the rest of the house. I don't think you should seal it at all, but if you do, use something that's both non-flamable, and which doesn't conduct heat well.
You can't seal it with anything flammable. If you want to stop the cold air from flowing down along the space, you can use metal flashing.
HTH,
Paul
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