In cold climates like Manitoba—closed crawl spaces are the best option. Under hot-humid conditions, warm, moist air enters the vented crawl space from outside and can condense on the cooler surfaces. Even when condensation doesn’t take place, relative humidity (RH) above 80% for an extended period can support mold growth and eventually rot wooden structural materials. Add A/C to the house, and the floor above the crawl space becomes even cooler—and any ductwork in the crawl space creates an added risk of condensation. In Winter other elements come in to play Cold air makes its way in to the space and dramatically cools the floor and living space above greatly effecting living conditions and energy consumption.
At Red River Spray-On we specialize in closed crawlspaces. In closed conditioned crawl spaces insulation is normally placed around the perimeter and not in the floor. With perimeter insulation the house is coupled to the cooler temperatures of the ground, and this can reduce the overall amount of A/C needed to cool the space above. When closed conditioned crawls are used in heating-dominated climates like Manitoba, this same ground coupling can actually increase the heating load of a house, but that may cost very little compared to the cost of damage done by moisture brought in by an unsealed crawlspace envelope.