Get the Ventilation Right

by Jonas

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Posted on 04-12-2020 04:49 PM

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Basement root cellar ventilation

The easiest option for building a root cellar is to section off a part of the basement (or maybe even the whole basement, if you live in an old farmhouse) for produce storage. Old dirt floor basements without heat are great for maintaining proper temperature and humidity levels. Select an area with an existing  window if possible, and use the window for ventilation. 

Yes, pretty much. Traditionally, root cellars were often built in the earth underneath pioneer homes to keep food from freezing over winter. These days basements are still a great place to build a root cellar. This below-ground space is naturally cooler. Choose one corner of your basement (ideally the northeast or northwest corner), build two insulated walls to define your root cellar space in the basement, then install an insulated door and shelves. You’ll also need to install two 4” diameter vents to the outdoors. One vent opens at ceiling level, and the other one at floor level. This encourages ventilation of the entire root cellar space, and that’s important for two reasons. First, you’ll want to admit a controlled amount of cold outdoor air into the root cellar during autumn, winter and spring. Whenever you need to lower the temperature or humidity inside the cellar while it’s cooler outside than inside, open the vents and monitor temperature. The second reason for venting is to expel gases given off by produce.

Root cellars have been used for thousands of years and were essential before the times of refrigeration. Root cellars use properties of the earth to keep many crops cool like carrots, potatoes, carrots, beets, turnips, parsnips, cabbages & other crops cool and fresh during the winter months. A root cellar may be buried under the ground, in a basement corner or even made with garbage bins. Temperature, humidity, ventilation are all important aspects of a proper root cellar to prevent spoilage:.

When you say the root cellar

Making an underground root cellar was my fall project for the year 2010. This article shows step-by-step how it was designed and constructed, from the planning stage to the final result, including information on drainage, ventilation, and insulation. I'll explain the mistakes i made and how they were corrected (or how i learned to live with them!).

We decided that our little farm needed a root cellar to store our produce in. For those unfamiliar with the term, a root cellar is an underground room that acts like a natural refrigerator, maintaining temperatures in the mid 30’s f in the winter and mid 50’s in the summer.

More than anything, we want to create a great space for storage. But, of course, we also want it  to fit in with the look of the existing farm. We are fortunate enough to have an ideal location for the fruit cellar. We have a sloping hill that extends from the edge of the house to the farm below. That hillside also happens to face north, which is perfect for outdoor root cellars.

Martin, thanks for the response and the article. Funny that is shows floor trusses as that is what i am planning on using throughout the house, except in those areas where we need to dense pack, so the garage ceiling, root cellar, and the flat roof sections. The trusses are not cheap, and replacing them with closed web joists or dimensional lumber in those areas saves me some money. After reading the article, i think i am going to add 3" of open cell spray foam to the underside of the subfloor, just to be safe. I was planning on using solitex mento air barrier between the rim board and the joists and then tape it to the polyiso to create a continuous air barrier. Since there is no electrical or mechanical in the ceiling, the gypsum will act as a second air barrier.

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