Prepping the slab-on-grade foundation for our addition at Model ReModel 2022, remodeler Symbi Homes has beefed up its sub-slab insulation to maximize energy efficiency and comfort in this Zero Energy Ready 850 square foot in-law suite.
This includes two layers of R-7.5 XPS rigid foam insulation 24” deep vertically along the foundation wall and one layer of R-10 EPS foam insulation horizontally.
“If you want to build high-performance homes, especially in climates with cold winters, foundation insulation is absolutely critical,” explains Symbi CEO Nicole Tysvaer. “Overall, the upcharge for insulating our slab on grade is rather minimal, but the benefits in terms of comfort and energy savings are tremendous.”
The U.S. Department of Energy Zero Energy Ready Homes certification program requires a minimum R-5 vertical insulation for all areas where the foundation wall sits 24” or less below grade.