What is a good air barrier to use in settling spaces for log homes?
AlPhil47
| Posted in General Questions on
For my handcrafted log home, I will have settling spaces above windows to accommodate 3-5 inches of settlement. To minimize air leakage, I want to use an air barrier. It needs to be flexible as the log wall settles. Will Tyvek House Wrap suffice? Poly? Or is there a better material to use?
see attached schematic
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Replies
Alan,
Tyvek is not made to be an air barrier. For this application I would suggest SIGA Majpell. It's a low perm air barrier designed for the warm side. You can connect it to the assembly using SIGA Rissan. I'd suggest following that up and connecting the widow to the framing at the interior with SIGA Corvum 12/48. This will get you a good quality, long term air barrier, with the flexibility for settling that you want.
SIGA Majpell: http://www.smallplanetworkshopstore.com/products/SIGA-Majpell-5-252d-4.9-ft-roll.html
SIGA Rissan 60: http://www.smallplanetworkshopstore.com/siga-rissan-60-all-around-interior-air-sealing-tape/
SIGA Corvum 12/48: http://www.smallplanetworkshopstore.com/siga-corvum-12-48-window-tape/
Alan,
Three to five inches is a lot of settlement (but is realistic for a log home). Here are two other possibilities:
1. Finish up the air sealing later, after the logs have settled. You can always pull the window casing off and finish up the air sealing details in a couple of years.
2. Use a product like DuPont FlexWrap. But you'll need to leave room for the product to fold and crumple.
Air sealing a log home is something of a fools-errand, damn-near impossible to get right for the long term, since there are both seasonal and long term dimensional changes that never go away, as it adsorbs/releases moisture, and changes temperature. Is there any way to convince you to use a different wall assembly type?