We're building a small new home, and being only a few years into domestic food production and storage, could use input from more seasoned cellar users on what works for them. What would you do (or have you done) given the opportunity to design and integrate cold storage into a new build (or not)? Some have suggested to us NOT to integrate a cold damp space (root cellar) into a home you generally want warm and dry (site is 4B in Wisconsin), and I suppose that makes sense, though convenience of access is of course a consideration too. We don't really have a full 4 wall basement going in, unless I make a point of putting one in for the sake of cold cellar specifically. So far everything is sitting on what some call a walk out basement (main living level for us), others call it a slab-on-grade with north retaining wall.
Home site is 16% grade, so a nearby cave style cellar should be a natural fit if a better idea, but maybe it is more sensible just to attach it to home and have the excavators and foundation guys dig and pour walls for it while they are there anyhow? Maybe we want a cold DRY space (cold cellar?) integrated into home itself, and then also a stand alone wetter "root" cellar outside the home, maybe some kind of earth bag or easy block build. How about ventilation and temperature management for either. Are there any notable advantages or disadvantages to either style of cellar sharing one wall, or two or three, with other parts of the home? What are your thoughts? Any good resources on the fundamentals of design on cold and or root cellars? Thanks for any help!
In my zone 4b neighborhood, porches are commonly used as cold storage cellars. What that looks like is that an open to the elements front porch has a cement floor. Under that floor is a narrow room, with all cement walls, that is accessed from the basement. That way, the room can get cooled by the winter weather, and warmed by the basement. Another way that I have seen this implemented is to have an outside cement stairway (perhaps covered to keep off weather) going to the basement, and a cold storage cellar is located under the stairs, and again accessed from the basement. These rooms typically have a small window/vent that can be opened to introduce a bit of cool air if desired.
I have also seen pits dug into the floor of the basement. These are typically moister than those made as small rooms sitting just outside the basement.
In my 4A Wisconsin house we added a root cellar. It isn't ideal but it does work. We have a block foundation and a walk out basement with the main living area above. There was a poured cement root cellar installed in the 60's but it was 6' tall without a ceiling. It was on the North side but not in a corner. The walk out is to the West. I insulated the cellar with 2" of Styrofoam and raised the ceiling up to the floor joists (with Styrofoam in that ceiling). I added two 4" duct lines through the rim joist and put a small fan on one and a damper on the other. My theory was that in the winter the frost outside on the block and the colder air on the rim joist area would keep the room cold enough. The fan is for nighttime in the spring and fall when I want to cool the cellar off (60F days and 30F nights).
So, how did it work... The fan did cool it off in the fall. It was plenty cold in the winter. We actually had to crack the door to keep it from freezing. My biggest headache has been getting the humidity up. We have a cheap Menards humidifier going all the time in there and it can barely get over 50%. The room outside the root cellar (mechanical/storage room) is rather cool (60 ish) and is a great place to store the squash and canned goods.
So I'd recommend a separate root cellar with a dirt floor if you can. I don't know how to ventilate and temperature manage it but there are plenty of root cellar books out there with ideas. If it shared a wall with the house foundation it would probably make temperature control easier. As well as running lights/outlets. We find that we only go into the cellar once or twice a week to do our "shopping". So going outside to get into it shouldn't be that big a deal. Your idea for a cold/dry area in the house is great. Be sure to have outlets and lights in the root cellar. You'll want lights in there and outlets to allow for "adjustments" to the design in the future (humidifier, heater, fan, etc).
Thanks for the input guys. Your suggestions have me thinking of a few more things. First, I'm assuming a dirt floor simply allows more moisture to enter the space, is there any disadvantage to putting some rock down over that? Joseph, your mention of a pit dug out of basement floor really has me thinking. What about a cold cellar, with a pit style "rootier" cellar under part of the floor of cold cellar? It could be below a floor hatch door kind of arrangment, and the coolest moistest air might settle there in theory? I could even add water to that space, and it would humidify the pit most, and possibly aid in humidifying the rest of the cold cellar to some degree as a bonus. I do think what we need the MOST volume for is a less humid cold cellar, which I'm thinking will simply be at rear of a walk out basement garage arrangement, two walls are foundation walls direct to subsoil at least 6-7fet up wall on outside, one wall would be shared with utility room, and one wall would shared with garage. Seems like a reasonable ratio to me, kind of like the under porch format. If I ever needed more root cellar space I could add cave style cellar later. Does this arrangement sound sensible?
Nathan P. What you are describing at least sounds very similar to what my sister had built near Ellsworth, WI. A south downward sloping site was excavated for an energy-efficient home (solar water, lots of south-facing windows, etc.). Very square floor plan, and with 3 "basement" walls with a south-facing walk-out. I know she put in a root cellar, but now I can't recall if she simply walled off an area near the north wall of the basement or if a new root cellar was excavated out one of the walls. It may have been the former....I'll try to remember to check. But we are in an older farmhouse with a ~30 X 30' floor plan in which a root cellar (~10X12' dimension, cinder block with cement floor) was added off of one side of the house. The bonus here is that the root cellar essentially provided the foundation for a 10 X 12' addition that was made into an east-facing entryway (mudroom!!) that included a small bathroom, laundry space, and storage space. Properly placed shut-offs in the plumbing in the basement allowed for plumbing of the addition.....one could envision placing all hot water generation (solar or otherwise) in the addition and then not having it in the basement: For us this was crucial since basement flooding in this region is legendary. Our root cellar at this point is only accessible from the basement, but as others have noted it's not (or wasn't) uncommon to have double-doors across a cement entryway leading down into the root cellar from the outside of the house.
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Yes the dirt floor is to help keep the humidity up. Advantage is that I believe you can dump/spray water on it to keep the humidity up. I think gravel would be fine over top of it.
The pit under the cool cellar sounded good at first but you may not be able to keep it cold or ventilated enough. Once you get 6'-10 feet deep the ground gets a bit warmer. My uninformed wild guess would be 45-50 degrees. Maybe higher with a house sitting over it. Ideal root cellar temps are 33-40 degrees. Keeping air circulation in the pit would also be a challenge.
You might want to check your library system for root cellar books. The one I have that has lots of good ideas, options, designs and examples is Root Cellaring by Mike and Nancy Bubel.