Insulation technique for termite-free areas
Bare concrete foundation walls can look bad, especially if not screened by bushes and shrubs. However, there are several good ways to dress them up and add insulation at the same time. Foundation insulation panels, such as the ones made by Styro Industries, are one good-looking option. The foam panels are available in 1-, 1-1/2- and 2-in. thicknesses, in different widths and lengths, and with either stucco or aggregate textures. We paid $14 for each 2 x 4-ft., 1-in.-thick panel. The panels attach to concrete, stone or block walls with rigid-foam adhesive and can be cut with a utility knife or a circular saw with a masonry blade. Detailed installation instructions and retailers are listed on the company's Web site.
According to Styro, an uninsulated foundation accounts for up to 22 percent of the energy loss in a home. So insulation panels will improve your home's energy efficiency—and its looks.
Insulation option for termite-infested regions
The panels we show above are not termite resistant and could provide a bridge for termites to access the house. A termite specialist told us that installing the panels also makes it difficult to inspect along the bottom of the siding for termites. However, Dow Chemical (dow.com/Styrofoam) offers a termite-resistant insulation panel, called Styrofoam Blueguard, that you can install on the foundation's exterior, then trowel a finish over the surface. The 4 x 8-ft. panels are available in 1-, 1-1/2- and 2-in. thicknesses.
Wear gloves and a long-sleeve shirt when handling the insulation. Adhere the insulation to the foundation with foam-compatible adhesive, butting the joints tightly together. To cut the panels to size, score them with a utility knife and then snap them. Some building codes require a 2- to 6-in. gap between the panels and the siding for termite inspection.
Once the panels are installed, apply a stucco-like finish. We show a premixed acrylic finish by Styro Industries called TUFF II Pre-Mixed Coating (about $70 for a 5-gallon bucket that covers 80 sq. ft.). Etch the insulation with a wire brush just enough to take the sheen off the surface (this allows for better adhesion of the finish). Apply Sticky Mesh HD tape (also made by Styro; $40 for a 9-1/2-in. x 150-ft. roll) over the insulation, overlapping seams by 2 in., then apply two coats of the coating with a trowel or putty knife. Paint the coating using an exterior acrylic paint, if desired.