expandable foam and furnace flue vent?

[biglebowski]

:confused: expandable foam was around both plumb vent pipes and the furnace/hot water heater flue going through the roof. Vent boots were installed wrong and I was assuming they added this because of that but is it flammable ? around the flue vent?

[David McGuire]

I agree. They sell 800 degree fire retardant silicone that would be a better choice. They use it a lot on some vehicle exhaust and BBQ grills and ovens and even some of the pellet wood stoves. There is also that fire rope caulk/gasket stuff that they use on gas and electric ovens, I think it is rated at 1100 degrees.

[Matt Fellman]

:confused: expandable foam was around both plumb vent pipes and the furnace/hot water heater flue going through the roof. Vent boots were installed wrong and I was assuming they added this because of that but is it flammable ? around the flue vent?

Looks like a bad install for sure. Someone was likely trying to prevent leakage after a bad flashing install (not going to work) or prevent drafts (dumb idea) or ?????

btw.... welcome to the board. I like your name and loved the movie (my favorite scene was 'the dude' getting his head shoved in the toilet). You'll likely get better answers and generally more help around here if you post your real name.

[biglebowski]

btw.... welcome to the board. I like your name and loved the movie (my favorite scene was 'the dude' getting his head shoved in the toilet). You'll likely get better answers and generally more help around here if you post your real name.

thanks, ya movie is hilarious, would be great if they had a sequel . i didnt know my name mattered but ill change it if i can

[Michael Thomas]

Going back a step: is that b-vent?

1) If not, it's wrong, you can't vent through an unconditioned attic with single wall.

2) If so, it's wrong, you can't have any material - flammable or not - other than another appropriate portion of the listed vent assembly in contact with the pipe at that location.