Basement Walls

Is your basement finished? In an unfinished basement, the walls are usually bare concrete, stone, or block. These types of material transfer massive amounts of heat and energy from warm to cold, without providing much heat transfer resistance (R-Value) at all.

Insulating Your (Cold) Minnesota or Wisconsin Basement

One of the most effective ways to insulate a basement is to install a continuous layer of 1.5-3.0 inches of foam board directly to the foundation wall. Foam board can be either Extruded Polystyrene (XPS), which is the blue, purple, or yellow foam board, or foil faced Polyisocyanurate foam.

Foam board is secured to the wall using a compatible foam board adhesive and powder-propelled nails with large plastic heads to keep the foam in place. All seams are taped and sealed, and spray foam sealant is applied to edges. This wall insulation is oftentimes installed before rim joists are foam sealed, so that rim joist foam can lap onto and further seal the wall board.

This uninterrupted layer of foam board creates a monolithic air and moisture barrier around the perimeter, and is not susceptible to moisture damage or rot (as a fiberglass insulated, wood framed wall can be). A treated wood or metal-stud wall can be built inboard of the insulation layer and finished with any variety of materials.