Preferred Brand for Cellar Vapor Barrier

I’m building a wine cellar from scratch and after trying to research the preferred vapor barrier(s) for cellar applications, I have not found a definitive answer. Maybe I’m looking in the wrong places, but so far, many vapor barrier manufacturers seem to highlight usage under laminate flooring or even landscaping project. Since I do not want to ‘assume’ they would also work for a cellar, can anyone offer any insight, guidance or even personal preferences? Relatively new to WB, so apologies in advance if this is a dumb question…and thanks for any help or reassurances.

I used a 6 mil black plastic and it is fine. Used the same thing on the concrete floor before putting down the floating cork floor.

Thanks Paul. Sounds like generic, 6 mil polyethylene sheeting is just fine in this scenario.


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Tim - you can use that poly. The point is only to get something waterproof. Are you doing it yourself?

Thanks for the feedback, but according to DuPont, Tyvek is not a vapor barrier: Resource Center | DuPont

Q3: Is DuPont™ Tyvek® a vapor barrier? No, DuPont™ Tyvek® is not a vapor barrier. It is made with unique material science to keep air and bulk water out while allowing moisture vapor inside walls to escape.

Hi Greg - I am serving as a general contractor (sort of, at least; it’s really not my forte either, but much better than actually handling power tools!) and hiring individuals from the design all the way through construction. The carpenter was not 100% sure about the vapor barrier, so I started looking into it further and found less than specific guidance.

Disclaimer: No expertise in building or construction. I wrapped the exterior with Tyvek and filled the interior walls with closed cell foam. I see no downside to having moisture on the outside of the foam permeate through the Tyvek to the exterior wall. The problem with plastic is with time it becomes brittle and deteriorates. Roofs were always covered with “felt” but today there are better options.

Thanks, Michael. I see your point. The key difference is closed cell foam (more expensive), which if I’m not mistaken, also serves as a vapor barrier. I am using R-19 batt insulation (cheaper), which by default needs a proper/separate vapor barrier. That’s why I’m trying to educate myself and make a more informed decision. Thanks for the input.


That is my understanding as well. In that scenario, the closed foam cell is the vapor barrier, not the Tyvek.

I agree with others, a good 6ml plastic sheet, properly installed, should do the trick.

(And, don’t ask me what “properly installed” means. I just know if you do it poke holes in it, it won’t be a vapor barrier any more! [cheers.gif] )

Dupont Tyvek is not a vapor barrier.

Dupont website FAQs.

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

A fellow named Paul Fisette, in the Building & Construction Technology program at U-Mass Amherst, wrote the bible on this question:

At least back in 2001, he felt that felt was as good as anything else on the market.

The key question, though, is what happens to the moisture as it starts dripping down towards the floor.

And that’s a hard problem.

Ideally, the moisture would congregate on a concrete slab on grade [or, better yet, a concrete slab resting on bedrock], but if the moisture congregates on a floor made of non-pressure-treated wood, then you have big problem on your hands.

At the end of the day, in an high-humidity environment, water management is a very, very difficult [and, to a certain extent, arguably impossible] problem to deal with.

But you’ll sleep a lot better at night if your 43-degree wine cellar [within a very high-humidity 78-degree household] were made entirely of exterior grade components [pressure-treated wood, double-dipped or stainless steel fasteners, hardipanel rather than drywall, etc etc etc].

Because if you have water dripping down onto white wood, then eventually the white wood is gonna rot.

PS: Proper insulation helps a lot here - there’s an yuge difference between the best insulation you can do in a wall with 2x4 studs made of white wood versus 2x12 studs made of pressure-treated wood.

If you’ve got 2x12 pressure-treated studs for your wall, with 11-ish inches of insulation in there, and if you upgraded to stainless steel fasteners & hardipanel, and if it’s all sitting on a concrete slab in your basement, then you can sleep like a baby at night.

500 years from now, someone else can worry about whether or not the pressure-treated wood actually started to rot.

I put my wine cellar together myself in my basement. The inside walls are Owens Corning rigid foamboard, which serves as the vapor barrier. The seams were taped with vapor barrier tape. The ceiling has foamboard, but is not taped, to allow any moisture that does build, to escape out the ceiling. The floor is just concrete. The cellar is actively cooled. Through one summer I have had zero moisture issues - knock on wood.

What do you mean by plastic not lasting long enough ? I used a very thick plastic (sorry, but I don’t recall the exact thickness) when I built my wine room 20 years ago, and based on thermal imaging, it’s still working very well.

I used closed cell sprayed icynene foam. Not inexpensive but has perform beautifully as both insulation and vapor barrier. Do not have to worry about holes in plastic or leak around rigid foam.

We used 2 by 6 wall construction with R-21 insulation. As I recall they used a 10 mil barrier normally used for basement crawl spaces. The contractor said it was the best thing he’d found for walls in the Napa area and the concrete floor sealed with epoxy, so the cool concrete naturally reduces average room temperature.

Thanks to one and all for your collective input. In addition to the feedback here, I called a cellar building company today and was told there is no difference between applications (i.e., a vapor barrier used under flooring—typically 6 mil polyethelyne—will work just fine in a wine cellar). Pretty sure I’ll be long gone by the time the plastic degrades. HA!

Another vote for closed cell foam.