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Spacing OSB sheets in a conditioned garage?

Renovations102 | Posted in General Questions on

Hi Guys,

I’m headed back into the garage tonight to start hanging my OSB for the walls. In my dads garage, we did thin plywood many years ago, his garage is not air-sealed like mine and is not heated & cooled like mine. We got some buckling during humid months and  had to unscrew some sheets and rip them a bit to leave a gap.

On mine, I am debating the old “1/8” or so gap between sheets because my garage (as garages go w/ (2) large overhead doors) is quite tight, well insulated, & has a mini-split head for heating, cooling., and humidity control.

Should I still gap the OSB sheets even though the humidity will be relatively low year-round? I’m in 4-seasons, zone 5B

If gapping is still recommended, can I caulk the gaps w/ my NP1 to air-seal them as it has pretty good flexibility?

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  1. Expert Member


    Most commodity OSB, like that sold in the big box stores, is nominally sized 8ft x 4ft but is actually smaller, so incorporating a gap keeps you on y0ur stud spacing - and is good practice.

    Gap or not, if y0u using the OSB as an air-barrier you need to either caulk, or more commonly tape the seams.

    1. Renovations102 | | #2

      I guess I'll keep the gap although part of me says I won't have a buckling issue.

      I'm going to caulk vs. tape as the OSB will be exposed and I don't want to look at a mile of tape & NP1 will be a lot tougher to compromise should something impact it.

      Thanks for your input

      1. Expert Member
        MALCOLM TAYLOR | | #3

        You may want to block at the OSB joints. Then you can bed the sheets in caulking (or acoustical sealant, or foam gaskets), and it won't be visible from the interior.

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