Air barrier seal at top plate
Hi all,
Looking for a comprehensive explanation, or link to an article, that goes into detail about how to seal the air barrier at the top plate, please.
Will do my best to articulate the concern:
The zip shesthing will be sealed with a good tape to the foundation, creating an air barrier at the sheathing layer; however, the zip won’t be taped/sealed at the top plate, combined with what ever else needs to happen, leading to an incomplete creation of an air barrier at the sheathing layer.
Instead, the guess would be the house would be “forced” into relying on the drywall, at least at the top plate region, for the air barrier.
Therefore, due to lack of complete air sealing at the drywall layer, due to not sealing electrical penetrations etc., The house has neither a complete air barrier at the sheathing or drywall layer.
Hope this make sense and can be answered as it would be of great help.
Thank you.
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Replies
A few more details may help. Is this new construction still in progress?
"the zip won’t be taped/sealed at the top plate"
What's the situation that is preventing this?
You need to think of the air-barrier as a continuous 3-d entity. This means the ceiling (or roof) plane is included. If the wall air-barrier is the sheathing, you must connect your ceiling plane to your sheathing plane.
If you can't use tape on the sheathing due to it extending beyond, perhaps a bead of sealant, or a gasket (such as from conservation technologies)?
Depending on access, you could perhaps tape membrane/drywall/wood (top plate even) to the inside of the wall sheathing above the top plate, and then tape the same to the ceiling air-barrier. This would be difficult if rafters/trusses are already on the wall.
If you are being diligent, realize that the gap/seam in the sheathing (I'm assuming the seams are taped on the exterior) will need to be sealed here since you're working from two different sides of it; either by extending tape up and continuously over the seam, or with a squirt of sealant filling the gap from inside to out at the plane of your interior seal.
https://www.finehomebuilding.com/2014/03/05/a-practical-air-sealing-sequence
https://www.jlconline.com/how-to/insulation/air-sealing-that-works_o