Air sealing details
SaltandPine
| Posted in General Questions on
I’ve seen a lot of air-sealing details where the top plate of a wall assembly is wrapped with something like Siga Majvest to connect the exterior wall sheathing to the underside of the inside roof framing, which makes sense to me assuming it’s continued to connect to all sides. My question is: should a similar approach be applied to wrapping under the bottom plate? Specifically, would it be beneficial to connect the exterior wall sheathing to the top of the subfloor , assuming the subfloor seams are already taped?
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Replies
S & P,
The difference in the two conditions is that the subfloor extends out to the exterior sheathing, so you already have continuity if you seal the two at the exterior. There is no need for a separate material to join them across the wall plates the way there is at the ceiling.
Using the subfloor as an air-barrier also only makes sense if the building is open to below, or has a vented crawlspace.
Thank you for the clarification Malcolm. Makes sense now.