- Q.What is the best way to protect
exterior foundation foam insulation where it projects above
A. While there are a number of
trowel-on or paint-on coatings on the market, I have found that
most of these coatings chip easily. My choice is a strip of
1/2-inch foundation-grade (FDN) pressure-treated plywood (see
illustration). It can take a lot of abuse and can be painted or
stained any color.