Case Studies

Crawl Space Insulation Case Studies: Cold Floors Over Crawl Space in Ashburn, VA

Wednesday, May 8th, 2019 by Justin Dobson


This older home in Ashburn, VA was built entirely over a crawl space.  Cold air was entering the crawl space and making the floors above very cold - especially in the extreme arctic blast we were having!  The homeowner also wanted to make the house more efficient and keep the heat in longer. We used spray foam insulation to "encapsulate" the attic too.


Comfenergy was called in to solve this problem by "encapsulating" the crawl space.  This entails turning the crawl space into a finished space or "conditioned" area.  The Batt insulation on the crawl ceiling is disposed of, and TerraBlock foam insulation in installed on the dirt floor of the crawl.

CleanSpace 20 mil thick anti-microbial vapor barrier is then laid over top of the TerraBlock.  Finally, the entire exterior of the crawl (including rim joists) are sprayed with foam insulation.  Now the crawl space is heated by the space above and the floor stays warm.

Project Summary

Evaluator: Mike Dowling