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Baffling for Gas Tank Venting Pipe That Exits Through Roof Deck

Lindaloowho | Posted in General Questions on

Hi All,

This is an unfinished vented attic in Southern Ontario.

I am using a piece of Aluminum and high temp caulk to air seal the Gas Tank Vent Pipe coming through the ceiling, bought some Roxul to surround the vent  and some metal lath to hold the Roxul in place. This way, I can use fibreglass on the remaining attic floor.

Problem is, I used foam baffles in the rest of the roof deck bays and the gas tank vent goes through the roof deck at the placement of the baffle. I can’t have the vent touch foam, right? Do I build a baffle for this bay? What material would be appropriate?


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  1. Expert Member


    If it's a vented attic, and the baffles are just to keep the eaves clear of insulation, you can remove the baffle and rely on the ones around it for air flow.

  2. Lindaloowho | | #2

    Thanks Malcolm,
    The baffles also serve to prevent the attic floor insulation from touching the roof deck. Any suggestions to prevent this without a foam baffle?

    1. Expert Member
      MALCOLM TAYLOR | | #4


      You are fine having the insulation touch the roof deck for one rafter. The most common practice here by production builders is to only have the minimum code required area of ventilation at the eaves, which usually adds up to every second bay. The ones in-between are blocked by insulation. Not great practice, but causes no real problems.

      1. Lindaloowho | | #5

        Okay, great. Thanks for your help, Malcolm!

  3. Lindaloowho | | #3

    Can I use a piece of plywood (on furring applied to the roof deck) inside that particular roof bay? To prevent the insulation from touching the deck?

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