Air barrier on floors?
bsavoie
| Posted in Green Building Techniques on
I am currently renovating a 1960’s ranch home, adding two additions. The house has been fully gutted. I intend to cover the existing sub-floor ( pine boards on 45 degree angle) with 3/4″ Advantek, and screwing the floor in place. The foundation consists of a partial basement and crawl spaces (which I intend to seal and condition). Is there any value to putting down an air barrier before the new sub-floor, and if so, what would be recommended?
Thanks
Bill
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Replies
Bill,
The new subfloor is your air barrier.
If you are worried about air leakage at the Advantek seams, you can (a) include a layer of rosin paper between the old subfloor and the new subfloor, and (b) caulk the Advantek seams.
Bill,
Some of the new subfloor systems have gotten so good at joining that they now include drain holes to let water drain and not create standing puddles during construction. They can surprise you at de-pressurization during a blower door test and can pull sawdust up to head height (my eyes...my eyes!).
If you see any weep holes you might add a layer of good tape (Advanteck has one too: Zip Tape) to the top of the subfloor at all seams. It certainly has served as good practice to reach Passivhaus airsealing levels of 0.6ACH 50.
Taping the face of the subfloor can often be the simplest approach.
In our house I installed a layer of AC ply over the diagonal plank subfloor. I ran a bead of construction adhesive in all of the joints between sheets as I pushed them together (as well as gluing them all down to the planks). This is good for minimizing squeaks as well as air-sealing.