The structural integrity of a building starts with the foundation, and this part of the house is extremely challenging in the cold climate and difficult soils of Alaska. CCHRC has conducted extensive research and demonstrated experimental foundation systems designed to improve the energy performance and durability and lower the cost of building foundations.
CCHRC's foundation demonstrations include:
Insulated mat foundation
This innovative foundation is designed for permafrost soils as a more energy efficient alternative to a more conventional raised foundation. It is built on top of a gravel pad and consists of steel floor joists elevated from the ground with EPS foam board, and polyurethane foam sprayed through the joists against a geo-textile mat. The idea is to thermally isolate the building from the ground so heat from inside the home does not disrupt the soils. The long-term performance of these foundations is still being studied.
Adjustable piling foundation
Pilings are often the best solution for extremely unstable ground. CCHRC demonstrated several steel piling foundations, which are driven deep into the ground using a pile driver. These foundations are popular on permafrost, as the soil freezes against the pile to further stabilize the foundation. In wet regions with permafrost, like the Yukon Kuskokwim, even pile foundations must be adjusted periodically. CCHRC uses an adjustable bracket welded to the top of the pile so occupants can level their house by hand if necessary.
Adjustable cribbing foundation
This raised foundation is a rigid wood frame diaphragm designed to thermally isolate the building from the soil, span inevitable movement, and be leveled over time. These foundations are placed on well-compacted gravel pads. They are close to the ground, minimizing the effect of cold winds. The floor beams rest on adjustable saddle brackets, on top of a series of treated wood pads.