How do you insulate a crawlspace with dirt floor?

sal Bellicoso
Updated: Aug. 7, 2020

We have a cottage with a crawl space near Halliburton, Ontario,Canada.  It has a solid block perimeter but has a dirt floor. Also, there is a very large rock under the cottage which makes the crawl space uneven-  ranging from 2 ft to 4 ft high. We have aluminum vents in the block foundation that slide open with a little screen. We have rigid foam panels on the concrete block walls (2 inch) The cottage is 900 square ft. To complicate things, we have just made a 400 square foot addition on concrete piers which is also not insulated. 

Currently we have a pump bringing water from our lake. We close down the cottage for the winter and drain the water for the season, we would love to insulate and try to make it a 4 season cottage. We are not sure if I should insulate the ceiling of the crawl space or to simply try to get a floor. Some people say we can get foam insulation sprayed in which will harden on the dirt floor.

We are currently power venting the crawl space to protect against radon gas.  What would be you be advice as to how to proceed for insulation/winterization/moisture?

At this point, I’m thinking to simply put a 6 mill poly on the dirt floor to keep the moisture out  and to put rockwool in the ceiling of the crawlspace with no Vapor Barrier….  we would very much appreciate your input and advice. 

Cheers, Sal

Responses (2)

Melody Summers
Melody Summers 3 years ago

Hi Emmanuel! 

CAn this insulation be used on dirt crawl space floors?

Thermoquiet , Thermal Acoustic Insulated Underlayment