Heidi Peters

My grandma had a house that had a cold cellar that was excavated into granite base rock that the house was built on in the 1970s. It had an air intake on the bottom part of the door and also on the exterior wall near the ceiling. No insulation on the walls as the cellar was part of their basement that was only used for storing garden tools, bicycles and similar items. I suppose the granite kept the temperature very consistent all year round. She stored her preserves there and some root vegetables. She plugged the upper air exhaust with a rag when winters got too cold. I have issues with mold spores like yourself, but didn't have issues with that cellar. It was a really simple design and is still in use by the new owners.

Thank you John!

Hi Beau! I don't have a root cellar yet in my yard, as I'm still working on other projects, but my relatives and friends do, which is where I'm learning from hands on and there are also research papers available in Finnish to draw knowledge from if you need translating. I find your project very interesting and educational. Please keep us posted on your progress.

I know the humidity in a cellar can be very local and seasonal. Only observation will tell you what it is in each individual cellar. There used to be a consensus of letting the cellar air out during Spring and Summer, but that can lead to condensation inside the cellar as warm humid air touches the cool surfaces of the cellar, so the experts are now saying to keep the door closed as mold issues tend to come from too much moisture. How are you keeping the ground level moisture under control? You mentioned an additional air intake pipe being installed possibly. Will you be adding a drain at the same time?

I am planning on adding a cold storage room or "wine cellar" in my basement as my first food storage after working on my pantry. I will be insulating it from the heated part of the house and keeping the exterior wall as exposed cinder block, the floor is concrete. I will also be adding a low air intake and high exhaust to the room. The intake I'm planning on doing as an earth tube that drains any condensations in the pipe outwards of the house. I will also be learning as I go as to what the humidity levels are near the floor compared to the ceiling. Such a fun project be working on!

Airflow in a root cellar is important. Replacement air will come from underneath the door or next to it and exhaust air will go out from the upper portion of the back wall of a root cellar. It is possible that the opening at the end of your root cellar was used for dropping in ice or it was used as a coal chute.

Will you be lime washing your root cellar walls to prevent mold and mildew? How will you be disinfecting it annually?

Here's a simple recipe for lime washing the walls that I have from living in Finland where root cellars are still quite common:

5 kg slaked lime, (calcium hydroxide, Ca(OH)2.)
10l (equals 10kg) water

(in other words ratio of 1 part lime to 2 parts water in weight)

1. Mix lime to a small amount of water, until it resembles soupy porridge. Then add the rest of the water mixing it constantly.
2. Let it sit for 12 hrs.
3. Slowly mix it again and add more water if needed. It should look like milk, the consistency is also the same as milk. Lime wash paint is now ready to use.

Clean the walls with a brush or vacuum. If walls are made of concrete then mist them prior to paint application. When applying to the walls it will run like water, and it will look wet, which is part of the deal. It will eventually dry and turn white. Make sure to use a wide brush and criss cross overlapping each stroke as you paint or alternatively rub it in the nooks and crannies with a round brush.

As for maintenance. If you ever see brown spots, it is not mold, it just means that water has seeped through the paint. The spots will need to be brushed and washed off prior to adding lime wash and then once it is clean you can reapply the lime. Cement walls need to be treated more often than stone walls with the lime wash. Wear gloves and goggles when you apply the finish. Avoid wearing your Sunday pants, because the lime wash splatters everywhere.