Often promoted in southern Ontario, this theory has never, to my knowledge, been proven by any government agency or independent researcher in the insulation field. On the contrary, the unanimous opinion seems to be that it will cause, not prevent, condensation. Even efforts to drain condensation to the crack between the wall and the floor - common in Quebec, opens a pathway for deadly radon gas to come into the house. See Air Spaces in Walls -- Myth and Science.
Last Updated: Friday, October 20th, 2017, Created: Thursday, October 14th, 1999
MYTH: AN AIR SPACE BETWEEN THE INSULATION AND THE WALL PREVENTS CONDENSATION.