Hardie Wrap: Over sheathing or foam board?
The question is :Does it matter where the Hardie Wrap is placed? Our builder would prefer to place it over the Avantech.
1. 5/8” sheetrock
2. “smart” vapor retarder (+/-)
3. Roxul R-23 batts
4. Avantech sheathing (taped)
5. 2 1/2” of type X XPS foam (taped). Foamular F250 product is available in 2 1/2 (R=12.5)”.
6. Hardie wrap or equivalent.
7. 3/4″ strapping (+/- Coravent SV5 product on top and bottom of walls and windows)
8. Hardie clapboard siding
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Replies
My understanding is that from a building science perspective it does not matter as long as your window flashing is integrated with your WRB and not behind it (ex house wrap over the foam but windows flashed to OSB behind the wrb/foam).
Personally I like the approach of having the house wrap against the OSB.
Since you plan on taping the Advantech sheathing have you thought about using ZIP-System? It's also made by Huber (Advantech) and has the WRB integrated into the sheathing. I only ask because Advantech isn't cheap and I bet for about the same cost the ZIP-System would save you time and supplies from having to hang/tape the house wrap.
My two cents.
Frank,
I think you should probably read this article: Where Does the Housewrap Go?
-- Martin Holladay