CCHRC members and sponsors provide vital, sustaining support for our mission to promote and advance healthy, durable, and sustainable shelter for cold climates. Donations help fuel many projects, including sustainable prototype houses in rural Alaska, renewable energy tests, and the production of educational videos, publications and multimedia. Your contribution to CCHRC makes change happen by providing valuable support to our research efforts.
Slab-on-Grade Foundation Best Practices
On-grade foundations are a popular design in Interior Alaska. This project uses modeling software to address these questions:
A shallow frost-protected foundation relies on heat loss to the ground to keep the soils beneath the footing above freezing. What’s the optimal amount of subslab insulation to use to achieve this goal while maximizing energy efficiency?
The Design Guide for Frost-Protected Shallow Foundations (prepared by the U.S. Department of Housing and Urban Development) is based on the assumption that the bearing surface of the building foundation is uninsulated in order to maintain heat flow into the soil. What is the energy loss due to this strategy? Alternatively, what is the right amount of insulation that could be used beneath the foundation bearing surface that both saves building energy while maintaining frost-free soils beneath the bearing surface?
How much “wing” insulation do I need to use if I increase the amount of subslab insulation?
This project will help builders evaluate the most cost effective, energy saving, and safe insulation options for under the slab. A resulting online calculator will help builders and homeowners make decisions about foundation insulation.