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Community and Q&A

Plywood bucks still needed with 1″ continuous foam exterior insulation?

PatriciaCranberry | Posted in Green Building Techniques on

Climate zone 3. 2×6 framing 16″ o.c. 7/16″ OSB sheathing. House wrap. 1″ rigid foam. 1×4 furring strips, lap siding.

I’ve read the Innies or outies article that walks through the steps for an outie window (my preference). Do I need the plywood buck? Is it primarily for air sealing. Are the masonry ties to plywood/stud critical or can the window be installed with just the nailing fin?

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  1. PatriciaCranberry | | #1

    Did some further reading on the site...I think the picture frame of 1x4's (flat on top of the rigid foam), screwed through the nailing fin, through the "picture frame", through the foam and into the sheathing/stud is my proposed method.

  2. GBA Editor
    Martin Holladay | | #2

    In case you haven't seen it yet, here is a link to a relevant article: Installing Windows In a Foam-Sheathed Wall.

  3. PatriciaCranberry | | #3

    Just reviewed Thanks Martin!...regarding WRB: I am allowing builder to put WRB house wrap on my sheathing--I think he will do the best job putting it there rather than on top of the foam. ...the housewrap will be "the"WRB. But I also intend to tape the seams of the foam and flash my windows to the foam as the "pre" WRB. If the foam were to shrink, open gaps/pull tape loose, water would get past the foam and run into the house wrap and I should be okay. Counting on the rainscreen to let wayward water drain and dry.

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