Fixing an airsealing miscommunication
Hello all,
I’m working on new construction in a mixed humid environment. I specified tape be placed on all OSB seams, but when I visited the construction site I found that the seams had not been taped. The housewrap is already on, and I’d really rather not set the project back by removing the housewrap to tape everything.
My question is whether there is a good (or at least workable) alternative to airseal the OSB joints from the inside of the house? I realize this will not be as effective (or likely as time efficient) than if it had been done right to begin with, but I’m essentially trying to mitigate the problem.
I imagine that I could tape from the backside of the OSB (although from what I read I’d likely have to use primer to get the tape to stick), but that seems like it would be pretty fussy. Would it be kosher to use acoustic sealant, mastic, caulk, etc. on the joints from the inside, or would that prove problematic? The last thing that I want to do is inadvertently create durability issues.
For reference, I’m planning on using board and batten siding, with dense pack cellulose insulation in the walls. The walls are 2×6 framing, 24″ on center.
Thanks for any input,
Will
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Replies
Is the housewrap taped? If not I would tape that and not worry about the OSB. If building code requires that the housewrap be taped than I would make sure your builder does it since you're paying him after all.
I guess you could tape/seal the OSB seams from the interior side.
If you told the contractor in writing to tape the osb seams, tell him to remove the housewrap and do it as specified. This needs to be the contractor's problem, not yours. It won't take that long to do it right.
Homeowners need to get past the notion that contractor screwups need to be worked around, instead of redone, especially when the mistake is easily fixed. Why should you pay for taping or caulking?
John, thanks for the help. I think the tape from the inside would work as well, but I'm certainly not a building professional.
Stephen, unfortunately, it was a miscommunication, and I'm hesitant to place all of the blame on the builder. I thought I was being clear in my instructions, but the builder took something totally different away from the conversation. It's not ideal, but at the end of the day the blame falls on me for not making 100% sure everyone was on the same page. That being the case I'm not willing to have him take the hit on his crew's labor to redo it.
Thanks again for any and all suggestions!
I agree that removing the housewrap, taping the seams, and putting the housewrap back is not a huge amount of work and could be worthwhile. I also agree that it's good to aim to hold the contractor responsible ... but sometimes you have to pick your battles, especially if the communications were not clear and documented.
As far as doing it from the inside, something like acoustical sealant could work well, but:
1) The traditional Tremco acoustical sealant smells terrible and continues to smell bad for at least a month. It's made with leftovers from the oil refining process, so it's an unknown mix of hydrocarbons. It's a pretty good bet that at least some of those are bad to breath. My favorite alternative is Contega HF, available from 475.
2) It's a little tricky to know where to seal. If you seal just the studs that are behind seams, air could get behind other studs and travel to the seams. So you are best off sealing all stud/sheathing interfaces. But by the time you do that, it's enough labor and materials that you might have been better off taking down the housewrap.
Will,
Removing the housewrap and taping the OSB seams on the exterior is the right way to go.
On the interior, it's possible to tape some horizontal OSB seams (kind of) -- the ones that don't coincide with plates or a rim joist. But there is no good way to tape the vertical seams that land on studs.
If you want to try to address this boo-boo from the interior, the best way would probably be with sprayable caulk. Here is a link to a relevant article: Air Sealing With Sprayable Caulk.
Thanks to everyone for all of the advice. After reading your suggestions, I had the builder remove the housewrap and tape all of the OSB seams.
Thanks again for all the help!