Since this is early in the winter season, the use of insulated blankets could be preferable to take advantage of the heat within the soil below. It just takes some planning to make it simple and cheap.
If you are a real contractor you should have learned the local seasonal tricks and tips.
If it is very localized, some charcoal and a day or two does wonders. Placing heated concrete does also help because of the mass and thermal effects.
More information and information on the location is important since some people may think you are in FL or GA and not in Ontario or similar locations.
A GC that we do some work for has them. They claim that it will take 12" of frost out of the ground. I have no experience with them but I do have experience with ground heaters. We used one to take frost out of a commercial building so I could finish grade the floor for concrete. That will take 12" of frost out in 24hrs easily.
The electrial company that I used to work for had a small enclosed trailer with a water heater filled with glycol and it used a 60 amp 2 pole breaker. We had about 200'-250' of hose and blankets and it would pull about 8"-12" of frost out in about 24 hours. I think it would heat up to 160 degrees. Our blankets were not electric but standard insulating blankets
Contractor Talk - Professional Construction and Remodeling Forum
A forum community dedicated to professional construction and remodeling contractors. Come join the discussion about the industry, trades, safety, projects, finishing, tools, machinery, styles, scales, reviews, accessories, classifieds, and more!