Exterior Insulation for Foundation Walls

Multiple Plasti-Fab products are an excellent solution for the exterior basement wall application: PlastiSpan, PlastiSpan HD, and DuroFoam Insulation. This guide covers PlastiSpan HD, but keep in mind the other products can be used as well.

Insulating basement walls helps eliminate the transfer of heat and cold through them. This is a step worth serious consideration because it saves money in heating and cooling, while providing a more comfortable basement and more space for everyone to enjoy. Exterior basement walls are a little bit tricky (and dirty), so make sure you are up to the challenge and dressed appropriately.

The first thing to do is make sure that the concrete surface is dry and free of dirt. Then apply a damp proofing compound to the exterior face of the concrete wall from the top of the footings to above the finished grade. (If an asphalt emulsion is used, allow it to cure before installation of PlastiSpan HD.) Any type of damp proofing compound may be used, and one only needs to be applied if one does not already exist on the exterior of the wall.

Start in a corner and apply the PlastiSpan HD insulation from the top of the foundation wall to the top of the footing. Use a foam safe adhesive like PL300 to attach the foam. Measure and trim PlastiSpan HD insulation with a utility knife or fine tooth saw to cut around any openings such as windows.

When this is finished, place a 6" deep layer of coarse gravel against the bottom edge of the PlastiSpan HD insulation and over the drainage tile.

There will be exposed insulation that needs to be protected. PlastiSpan HD Insulation must be protected from the top of the basement wall to 12"" below grade to prevent damage. Stucco parging is one common protective layer that may be used.

When this is all complete, backfill the foundation wall to the required grade using backfill material that will permit drainage to the drainage tile at the bottom of the wall. Grade the soil so that the top soil is sloped away from the foundation wall.

The exterior basement walls are now insulated.