Taping interior seams of exterior wall (plywood)
Hi,
We have unfortunately gotten to the point where we are now finalizing the exterior wall installation of our new build and it will be raining for the next few months, then likely snowing, before putting the siding on (thats if we get the chance to put the siding on this year)
I want to try and create as tight air barrier but all the exterior wall tapes require the plywood to be dry. Would it be worthwhile taping the interior seams of the plywood?
I know this will likely take a lot longer and not be as effective but just trying to figure out if I should spend my time doing it rather than just leaving the seams open
Any suggestions?
Thanks
Curtis
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Replies
Curtis,
I believe the general advice is to use a high-quality caulk since tape can be a lot more expensive. You could also check into Aeroseal, which probably would be easier and more effective (and likely at a higher price-point than either of the DIY options).
Taping the interior isn't a good option imo. Most of the seams will lie on a stud, and you'll have no clue where the seams are from looking at it from the inside. I've personally done this with spray foam, I ended up foaming a square around each stud bay rather than spending the time to go outside to figure out which studs have a seam.
I suggest using a polyurethane based sealant on the outside or otherwise something that is moisture cured. You probably can't apply it in an active rain storm, but should be good if just damp. Also don't apply during or overnight freezing temps. Most should cure in 24hrs.
I recall a matt risinger video using prosseco (that we can't get here in Canada). He was talking about applying it to window openings after a rain event.
Unless your sheathing is sogging wet, I would try to tape the outside seams. It really is the best in terms of air sealing and long term durability. I've had good luck with Henry flashing tape + primer combination (primer is key), it seems to stick incredibly well to any surface I've tried.
State of the art fluid applied flashings use Silyl-Terminated-Polymer (STP). It's amazing stuff. It is moisture cured and thus can be applied to damp (but not dripping wet) surfaces. Henry's version is called Air-Bloc LF. It comes in 20 oz. sausage cartridges. Prosoco has a family of products. The flashing is called R Guard FastFlash. They have a slightly cheaper product, R Guard Joint and seam filler. It no doubt has some inert filler to give it more body for filling seams. It is meant to be followed up with FastFlash. They also come in sausages. The most widely available seems to be Huber's Zip System Liquid Flash. It comes in sausages as well as 10.3 and 28 oz. cartridges for standard caulking guns. Amazon sells the 10.3 and 28 oz. cartridges.