Crawl Space
Crawl spaces are not a common foundation type in Minnesota; yet, they may provide a viable and affordable alternative. A crawl space can be less expensive than a basement because footings only extend to frost depth and the slab can be replaced with a durable moisture barrier. However, a crawl space achieves the desired raised floor appearance and feeling of warmth. Depending on the height, crawl spaces can be accessible and contain mechanical equipment, ducts, pipes, and wiring. Traditionally, crawl spaces were vented with outside air to remove moisture. This requires insulation in the crawl space ceiling and means pipes and ducts are open to outside air. Research has shown that in most climates, vented crawl spaces are not effective in terms of energy use and moisture control. Therefore, an unvented crawl space is recommended. An air-tight moisture barrier on the entire floor and walls in addition to wall insulation is essential. The wall structure may be concrete, concrete block, wood, or a pile-type foundation. A shallow frost-protected foundation with horizontally extended insulation can be used to reduce the footing depth of a crawl space. To minimize cost and material use without compromising the quality of above ground space, a crawl space on a low -ost pile foundation may be an optimal solution for affordable housing. Piles could be placed at the appropriate depth and filled with concrete. The wood floor would then be supported on steel beams connecting the grid work of these pipes. However, a thermal perimeter skirt is required to maintain a conditioned crawl space.