Details for Insulating a Slab Perimeter
In New Hampshire, Chris Roche is pulling together plans for a new energy-efficient home. The slab-on-grade design calls for double-stud walls insulated with dense-packed cellulose, what Roche believes is the most economical and practical approach for getting the walls to R-40, or beyond. Roche has paused at an important detail: the layer of rigid foam insulation that separates the concrete foundation wall on the outside from the slab on the inside. Roche writes in a recent Q&A post that just about every foundation design for a slab that he’s seen either puts all of the rigid insulation on the outside…