So I reviewed all of the great topics and posts on DIY wine cellars, but I have a specific question that I did not see addressed previously, so here goes:
I have a room in my basement that is perfect to use as a wine cellar. My basement was built using the “Superior Wall” foundation system, which basically consists of poured concrete around styrofoam insulation. This system is ready to be finished as it comes with precast metal studs.
Here is a picture of what this looks like (generic pic, not from my wine room):
The room is approx 6’ x 14’, with three of the walls completely underground. The fourth (short 6’) wall faces the inside of the basement, and is where the entry door will be.
My specific question is: Do I need to install vapor barriers on the walls, since they are made of poured concrete and already have built-in styrofoam insulation? Also, I need to insulate the ceiling, between the studs. Do I need to install a vapor barrier in the stud cavities first? Or after I install the insulation, facing the inside of the cellar? (I was thinking about using regular fiberglass insulation between the studs)? Lastly, should I seal the concrete floor?
Paul - I think you need a vapor barrier everywhere. The concern you face is that the cool air of the wine cellar may cause condensation on the “outside”, which could include against the concrete walls if they’re warmer and any moisture travels through (which is still can). You want the vapor barrier to go on the outside of the studs from the wine cellar (ie., insulation is facing the inside of the cellar).
Same thing for the ceiling - you want the vapor barrier up against the subflooring of the first floor.
My suggestion is to look into spray foam (closed cell) which will act as a vapor barrier as well. It’s probably going to be easier than trying to weave in a plastic vapor barrier around the studs and joists.
You still need a vapor barrier. Think of it as building from inside out. Reverse engineering would say: Finish materials inside cellar, stud it, add insulation, then wrap the entire structure with vapor barrier. This question comes up frequently. The foundation you speak of will not offer you protection from water vapor.
We all agree on the vapor barrier. As for whether spray foam or other additional insulation is needed, that largely depends upon the r value of your wall. Do you know what it is - and are you really confident that itwas installed correctly?
There is old school and new school when it comes to building a temp/humidity controlled wine room.
I would suggest using closed cell foam in the ceiling/wall stud cavities - this will give you a perfect vapor barrier and is approx. R7 per inch. In 2X4 framing this would give you approx. R19-21. I also call this method “stupid proof”.
Old school is wrapping the entire envelope with a 6mil visqueen (very problematic) and then using insulation to achieve the ideal R value (at least 19). If using this method I would stay away from batt insulation because if the vapor barrier is breached you could end up with a major mold problem.
Also - when sizing the refrigeration stay away from companies that will “guess” based on cubic feet - you should work with a company/manufacture that offers a thermal load calculation - this will keep you from having many different types of problems.
dont let anyone tell you concrete has a good R value or that it wont allow moisture drive
If you have any questions just let me know - hope this helps.
I also have considered making this a passive cellar for my regular drinking stuff, as I currently store my really good stuff at an off-site professional wine storage facility, and might continue to do so. Does making this a passive cellar make any difference as to whether I install a vapor barrier or not?
If passive and will always be that way, don’t need the vapor barrier. If you, or a future homeowner, desire to ever convert,my will be looking at a lot of demo to make it climate controlled. If I were you, would go ahead and make it climate ready now while you still can. Never know what you may need in a couple years time.
