Vapor Barrier Necessary???

Hello all. I would like to install a cooling unit in my 500 cubic foot wine cellar, but would like to avoid ripping out all the racking and walls to install the vapor barrier and insulation they way is needed. My cellar is in the basement and so is already in a pretty stable cool area. Two of the walls are against concrete and the floor is tile. What's the risk if I go without the barrier and added insulation?? Thanks!
Original Post
that is a very good question...anybody?......
.....the whole point of the vapor barrier is.... "no water in--no water out"....and perhaps to help with not only humidity control ... little or no fluctuation in water content in the cellar's airspace ...but also to a much lesser degree--->temperature control (keep in mind the analogy of rescue aid helpers putting on/wrapping the victim with one of those silver foil-like blankets that help to keep stable temperature...they really work like h&*$ ...)
...Do you have a sauna or steam room nearby or even a bathroom within the vicinity of your cellar...if the answer is yes then a vapor barrier is paramount...
I suppose it depends on the climatic conditions around your cellar. Ideally the humility in a wine cellar should be around 60 to 70 percent.

If your cellar is consistently drier than that, in theory the corks will dry out, shrink, and allow wine to seep out and, worse, oxygen to get into the bottle, where it will adversely affect the wine (that's the theory -- I've never actually seen it happen, even after living for 29 years in the desert climate of the San Fernando Valley).

OTOH, if the cellar is too damp, mold might grow on the labels, eventually ruining them, and they might fall off the bottles if the glue gets damp. I've seen some of this on older bottles, but it's never been a problem for me, and I've never heard of the mold actually affecting the wine itself.

I live about 500 yards from the ocean, and my air-conditioned cellar usually stays around 60 percent humidity. However, the house is relatively new and thus well insulated and swathed in Tyvek housewrap. Nonetheless, my guess is that your cellar has to be in a pretty damp area before excessive moisture is much of a problem. Still, if I were building a new cellar, I'd include the moisture barrier on the theory that it would help maintain constant humidity.
Thanks for all the feedback. The basement is finished, so it's heated and cooled. But it's always much cooler than the upstairs. And the HVAC system includes a humidifier. I imagine the vapor barrier allows the cellar unit to work less and last longer. I just wonder how much longer and if I would be ruining the walls by letting moisture in/out. That will help determine if its worth the time and money to rebuild the walls and disturb my friendly wine!
I don't know if this is even correct, but this is my very basic understanding from when I built my cellar. The insulation is basically to prevent your cooling unit from running continuously. The vapor barrier is to prevent the excess moisture from coming into the cellar. Especially in your case, if you have a humidifier in you HVAC, the warmer air in the house is already holding a lot more moisture than the cooler air in the soon to be chilled cellar. (Cooler air loses its' ability to hold water which is what relative humidity measures.) If there is sufficient moisture in the warm air, when it gets chilled, the moisture has to go somewhere and will precipitate onto surfaces in your cellar or inside your cellar walls. That's when mold becomes an issue. The point of the VB is to prevent this from happening inside the cellar and more importantly, inside the framing of the room. That's why it is always recommended to put the VB on the warm side of the room so if mold does occur, it occurs on the drywall and not in the framing. I don't know at what rate the mold will occur and I suspect your conditions will have to be horrific for it to be an issue in the medium-long run. As for insulation, the most important thing to insulate is the ceiling (and the interior walls of the basement). As you already noted, the basement is cooler than upstairs so that will be the place where the most heat transfer will occur. So if your cellar is completely uninsulated from the interior walls of your basement and the ceiling, it will probably cost a lot to run the cooling unit. In a few years time, that cost will probably surpass the cost of opening up the walls now and adding insulation. But if you're going to do that, might as well put in a VB.

Again, I don't know if any of this is true but just my hypothesis based on my own observations and some reasoning.
This subject has been discussed so many times... But here it is simply put. You MUST put in the vapor barrier on the WARM side of the wall........
The reasons are not really anything to do with the cellar itself. It is because you have (in simple terms) a Hot side and a Cold side..... Same as in any building. (Go ask someone in Canada how much water damage they get over winter to the actual structure of the building if they don't have a vapor barrier). The warm air hits the cold air (inside the actual wall basically) and there IS water in that air, no matter what you may think. So the water condenses inside the wall and that is where the problems will occur... Because it is inside the wall you won't notice it until it is way too late to make it a simple fix.

So put the vapor barrier in now before you find the bad smell/ rotted walls/rotted foundations in 2-5 years time.

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