Root cellar insulation

insulation

Building a root cellar in corner of full basement. No water issues. Humidity is relatively low in winter (SW Montana).

Details:
The root cellar will be located inside a full basement . The basement is poured concrete and is heated. The root cellar is going to be placed in a corner where 2 sides will remain bare concrete walls. The two adjoining walls that complete the room are 2×4 construction. It will be cooled by cool air from outside via duct work dropping cold air to bottom of room. There will be a warm air “exhaust” near top allowing warmer air to exit to the outside. I don’t think moisture will be an issue as humidity is typically low even in winter and there is no water in the basement (bathrooms, etc)

For insulation, is it best to use XPS panels or are batts ok?

Best Answer

I would use plastic foam panels; they won't be damaged so easily as batts and never absorb water. They could be easily moved to prevent freezing in winter and expose cool soil in summer.