Home > Building > Frost Protection for Walk-Outs Building Posted on: November 12, 2012 Frost Protection for Walk-Outs By Ted Cushman Photos: Pete Sucheski Frost Protection for Walk-Outs 1. Structural Slab Thicken the slab edge to footing depth (typically, 8 inches to 12 inches). 2. Warm Edge Insulate the slab edge with 2-inch extruded polystyrene (XPS). Extend the XPS horizontally a distance equivalent to the frost depth in your climate. 3. Side Protection Where soil cover is thin, protect the sidewall footings with more horizontal XPS—again, insulation should extend outward as far as your local frost depth. Frost footings add cost to a walk-out basement. Instead, you can protect the slab edge with R10 insulation, keeping frost away from the house without the need to excavate.