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Community and Q&A

Air sealing guide?

Rocky12 | Posted in PassivHaus on


Are there any documents or guides out there that thoroughly going through all locations that should be air sealed?

This will be my first time trying to achieve an airtight home so I’m looking for all the resources I can get. I would love to study up.

With that being said, all the framing is done and sheathing is next. Is there any airsealing I’m not thinking of that needs to be done before sheathing?

I’m planning on taping all my seams on the plywood (exterior) to act as my air barrier. Also will have a vapor retarder in the interior which will also act as an air barrier (but am relying on the plywood to be the better of the two).

I attached one of the only guides I found but do not know anything about the credibility of International Association of Certified Home Inspectors.

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  1. GBA Editor
    Martin Holladay | | #1

    That's an excellent question, and I'm glad you're focusing on the issue.

    My own article on the topic is called Questions and Answers About Air Barriers. My article lists several areas to focus on, and provides links to helpful resources.

    For a comprehensive document (other than GBA articles), we've always recommended Air Sealing: A Guide for Contractors to Share with Homeowners.

  2. Rocky12 | | #2

    This is great Martin. I will read over your resources this weekend.

    Thank you!

  3. user-1072251 | | #3

    you need to do a Blower Door Test after framing and before insulating. That way, you can find the leaks and fix them before they are buried in insulation or covered up.

  4. GBA Editor
    Martin Holladay | | #4

    While you are 100% right, it's also essential to engage in air sealing efforts well before the blower door person shows up for the test. Air sealing efforts start the day after the concrete contractor strips the foundation forms.

  5. Rocky12 | | #5

    Thanks Bob. I will do that. What's the best way to do a blower test myself?

    Are there any obvious airsealing locations I should focus on before sheathing?

  6. Expert Member
    Dana Dorsett | | #6

    Calibrated blower doors are a bit pricey for the DIYer, and training on how to use it well is more than just watching a few YouTube instructionals.

    While it's possible to do quite a bit of leak chasing with just a ~$90 reversible window fan (eg. Lasko 2155A) and a smoke pencil, with a calibrated blower door it's possible tell just how much more tightening up there is left to do to hit tightness targets as the work progresses. A blower door can move quite a bit more air and sustain bigger pressure differences than a big window fan too, which makes finding leaks easier. At 50+ pascals even small leaks are often audible.

  7. GBA Editor
    Martin Holladay | | #7

    You really need to hire a blower door specialist to perform a blower door test. For more information, see Blower Door Basics.

  8. STEPHEN SHEEHY | | #8

    When we had our blower door test, it was very helpful for the operator to crank the fan up past 50 pascals in order to help locate a few spots where a bit of tape or a squirt of foam was needed to seal a small leak.

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