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Last Updated: , Created: Thursday, October 14th, 1999

CONFLICT: DOES FULL HEIGHT INSULATION OF A BASEMENT WALL CAUSE FROST HEAVING?

Isolating parts of the house located underground from the heat of the house can cause freezing and shifting under certain conditions. Wing walls, carport posts, and the like are common frost heaving or ad-freezing candidates because these structural parts of the house are far away from the heat of the basement. Full height wall insulation will allow ice to form in the soil but this ice will not affect the foundation because despite all the insulation there is always a small heat flow from the basement into the soil that protects the wall.

Field stone foundations are an exception to this as they are structurally weaker and usually have poor drainage. The practice is to not insulate more than a foot below grade on the inside of a fieldstone foundation (protect that old mortar with heat) -- but you can insulate all you want on the outside and that will only keep the foundation dryer and warmer.


Keywords: Frost Heaving, Frost, Basement, Insulation, Techniques

Article 788