Insulation around Exhaust Pipe

I can’t find anything specific about blown insulation around the exhaust piping as seen from the attic. I figure that the insulation should be removed since 1) it could be considered a fire hazard and 2) when it does get cold here, the insulation will become damp from condensation… Any suggestions?

If it’s combustible (cellulose), it should be no closer than the manufacturer’s recommendations (1 inch for a B-vent). If it’s fiberglass, I don’t see a problem.

If you’ve got wet insulation in an attic, that seems like a problem all by itself. Nevertheless, I doubt it would not be wet around a hot pipe.

It’s fiberglass… Just didn’t look right… I’ll have to add a comment about “Manufacturers Specs”… I couldn’t upload a photo cuz it was too big… Thanks Joe! I’ve seen water stains at the drywall around the exhaust on a few houses, with no stains at the roof cut… I thought condensation on the metal “plate” at the drywall cut was a good explaination…

I have called both Dura-vent and Amerivent and they both require 1" clearance of all materials whether combustible or not. What they say is that non-combustible materials can “conduct” heat to combustible materials and therefore should be kept away from the pipe. I know that sometimes it says right on the pipe “1 inch to combustibles” but some of the manufacturers say “1 inch clearance”. Confusing I know. Perhaps they should say “1 inch to conductibles”:smiley:

Duravent quote from their website–B-vent installation instructions: “Where pipe passes through the roof, maintain 1-inch minimum clearance to all combustibles.”

By your reasoning Charles, you can’t use metal straps to support the flue because the straps are nailed to wood on the other end.