Preferred Brand for Cellar Vapor Barrier

[Rich_Brown]

Another vote for closed cell foam.

Yep. Totally worth the extra expense IMHO.

[mdavis]

3-4" of closed cell foam

[R_Halbert]

Closed cell foam all the way…

[Mike_Q]

I will add another vote for closed cell foam here. It is the best R-value per inch and makes a completely impervious vapor barrier.

[Jeremy_C]

When using closed cell foam insulation as a vapor barrier, does it need to cover all surfaces? That is, all the studs must be covered completely with it (and if so, how does one apply drywall to them)? How thick does the foam need to be to be an adequate vapor barrier?

[Jeremy_C]

Bump.

I came across this quote: “…the wood framing provides sufficient inherent vapor resistance to maintain the moisture content within the safe range even in very cold exterior climates (10 000 HDD) and very humid interior conditions (50%RH in winter).” from a 2009 article, “Spray Polyurethane Foam: The Need for Vapor Retarders in Above-Grade Residential Walls”

I’ve seen examples of plastic film used as a vapor barrier and in those cases they always wrap around the studs. I’m wondering how this issue is addressed with closed cell foam as the vapor barrier.

[brigcampbell]

so if Tyvek is not a vapor barrier, and plastic doesn’t last long enough…what IS the proper vapor barrier?

We’re ripping off your dry wall and spraying closed cell foam then going over that with stone and old barn wood.

Just sayin

[brigcampbell]

When using closed cell foam insulation as a vapor barrier, does it need to cover all surfaces? That is, all the studs must be covered completely with it (and if so, how does one apply drywall to them)? How thick does the foam need to be to be an adequate vapor barrier?

Yes spray the studs, basically fill the wall.

Spray Foam Insulation - Wine Room

Touch 'n Foam 640 oz. Board Polyurethane 2-Component Spray Foam Sealant Kit...

[David_Fisk]

Tyvek is not a vapor barrier as others have mentioned. 6mil or 10mil poly is a vapor barrier. More mil thickness = more durable, but also a little harder to work with, but either will be effective if installed correctly. Make sure to tape the seams. I have not experienced plastic deteriorating inside of a wall. Closed cell spray foam insulation can also function as a VB, although more expensive than batts. I haven’t seen felt used in wall construction in 30 years. I personally would use poly w/ no concerns.

[Jeremy_C]

When using closed cell foam insulation as a vapor barrier, does it need to cover all surfaces? That is, all the studs must be covered completely with it (and if so, how does one apply drywall to them)? How thick does the foam need to be to be an adequate vapor barrier?

Yes spray the studs, basically fill the wall.

Spray Foam Insulation - Wine Room - YouTube

https://www.homedepot.com/p/Touch-n-Foam-200-ft-Board-Polyurethane-2-Component-Spray-Foam-Kit-4006022200/204962748

Thanks, Brig, but I’m speaking of the interior aspect of the studs. That video doesn’t seem to show that aspect being covered.

[Jeremy_C]

One more time.

What have those of you who have used closed cell foam (as insulation and a vapor barrier) for your wine room done with respect to the studs? I just cannot see covering them with two inches of foam and then trying to secure drywall to that. So, I’m assuming that 3.5 inches of foam is sprayed between the studs but the interior aspects of the studs are left bare.