Home>Discussions>INSULATION & HVAC>Sealing around bathroom vent fan in attic
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Sealing around bathroom vent fan in attic

In about a week, I'm having 12" of additional insulation blown into my attic on top of the 8" of fiberglass that's already there.

I have a new bathroom vent fan (that's properly vented to the outside) that I need to isolate from the insulation since it's a non-IC rated unit.

I intend to build a box out of rigid foam insulation board and I'd like to know how much space I need to leave around the fan itself? How much bigger than the fan housing does the box need to be in order to be A) safe, B) not a huge void in the insulation and C) not trip the fan's thermal cutoff in case it gets too warm?

Once the box is in place, I'll spray foam seal around it in order to create as tight a seal as possible.

Re: Sealing around bathroom vent fan in attic

The fan manufacturer will have that spec and probably recommended techniques for your kind of install. Check their website.


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