Wine Cellar Insulation & Vapor Barrier

Why do you want a vapor barrier?

Good reference...

I'm not sure I am following you at all. Wine cellar or not, the vapor barrier goes to the living space side in PA and it should not be loose, it has to seal for the most part.

You want to keep moisture out of the > Hi:

The vapor barrier goes to the 'warm' side, which is the exterior wall. The vapor barrier needs to be contiguous across the wall, without staples/perforations soas not to allow condensation thru into the insulation. By 'loose', I mean that the vapor barrier is draped into the stud bays to make a seal across the wall, not cut and lined in each individual bay. The contractor has placed the FSK foil in the individual stud bays, which would seem to create gaps at the edges to allow penetration of moisture.

The contractor says they've done many like this in the past and that the FSK is a superior material to 6 mil poly. I'm willing to accept it if I can get confirmation that it's an acceptable/superior substitute method. But everything I've found on the Web indicates that the 6 mil poly is the only route... which is what gives me concern with the current implementation.

Thanks,

Ken

I think I follow you now. Does this mean they are putting up the wall and 'pushing' the insulation into the bay; foil face first? If so, the stud is still exposed so I think you are right; i wouldn't care for that.

In Pittsburgh the living space is the warm side, so we do it the opposite, which makes this work better. You push the insulation into the cavity and staple the foil face to both studs, then do the next one, stapling it in an overlap. I can't see them doing that unless they push the wall up after building it on the floor which is certainly do-able.

I'm an electronics guy- not a contractor though. That said, I built my own addition from the ground up and all of it was inspected.

Joe

. The contractor has placed the FSK foil in the

Hey:

It sounds ok to me if I'm reading you right.

If the studs are completely encased in vapor barriers applied on both the interior and exterior wall I would think they'd rot right before your eyes.

However,it sounds like both vapor barriers ( insulation foil and fsk?) are applied from the inside of the structure. The studs are not covered on the exterior side with a vapor barrier and free to breath. Right? That's good.

We use Tyvek here on the outside of the wall which is a more or less one way vapor barrier, allows the wall to shed moisture, tries not to let it back in.

Not sure if fsk is one-way vapor barrier or non permiable, but if the studs are not covered up on the exterior, I'm not sure it matters. Not a contractor so take it with a grain o' salt.

Take Care, Steve noobie Oregon

Steve, FSK is Foil Scrim Kraft. It's that stuck on vapor barrier they use on fiberglass insulation. At least I think that's what it is, I'm not a contractor either...

I agree it has to breath, we get a lot of moisture here too.

Joe

Steve:

Thanks for the reply. The exterior basement wall that I'm concerned about has 2x6 studs sheathed with OSB and I'd have to bet that there's Tyvek wrap between the OSB and fiber cement siding.

Your reply gives me concern in that everything I've read online at sites for wine racking & cellar construction indicate that the wall needs a contiguous vapor barrier of 6 mil poly. If I can't wrap the studs from the exterior, what I've read directs me to loosely drape the stud bays with the 6 mil and then place the fiberglass batting in the bays. Wondering if the combination of Tyvek on one side and 6 mil poly on the other could result in the rot condition you mention?

I'm not sure what to do about this...

Ken

spud wrote:

Ken:

Sounds all right.

No, Tyvek is permiable, more or less one way. Even with the siding, OSB and Tyvek, the wall can dry out from the outside. The objective of Tyvek is to let water vapor out but not in. You're good.

Re-reading your original post, the outside facing fsk is not continous, but 'draped' in the bays. The studs have opporutunity to breath. Ok here.

The interior facing fsk is sealed, or taped up along the studs, between bats to be a continous vapor barrier for the room vs. your question of using 6mil poly draped in the bays prior to installing the insulation. Either technique serves the same goal, to keep outside water vapor from entering the living space.

I think your cool Ken. I would not press for the 6mil and let it go with the fsk as is.

2 things. You want the wall to be able to dry out sometime so the studding must have acess to the outside. You're good here. And, you want to keep any outside water vapor from entering your living space. You're good here too.

Does that make sense?

steve noobie Oregon

Thanks, Steve. I had the contractor come back and replace the FSK in the exterior-facing wall with the 6 mil poly, so I should be good to go. Thanks much for your advice, much appreciated.

Best,

Ken

spud wrote:

Hi Joe:

I think it's draped and stapled inside the bay, installed from the living space. So the studs aren't covered on the exterior facing edge.

steve noobie Oregon

Thanks Steve, I just didn't follow it correctly. Sounds good and it's cheap insurance.

Joe

spud wrote: