This case study describes the University of Minnesota’s Cloquet Residential Research Facility (CRRF) in northern Minnesota, which features more than 2,500 ft2  of below-grade space for building systems foundation hygrothermal research. Here, the NorthernSTAR Building America Partnership team researches ways to improve the energy efficiency of the building envelope, including wall assemblies, basements, roofs, insulation, and air leakage.