Insulating and Parging Foundations
Covering concrete walls with rigid foam insulation and troweling on stucco requires experience with the materials.
Synopsis: A builder explains his method of insulating concrete foundations by applying a layer of rigid foam insulation and a coat of stucco over the insulation above ground. He experiments with a few approaches before settling on a single coat of cement stucco over a substrate of expanded metal lath.
If you’ve got the idea that a builder’s skill is an unchanging body of knowledge passed down through the generations, think for a minute about insulating a foundation from the exterior. Even in cold climates, what you used to see between the bottom of the siding and the grade was the bare concrete foundation wall. But these days, with estimates of heat lost in a house through the foundation running as high as 30%, what looks like concrete is more likely parging, or stucco, applied over rigid foam insulation.
Insulating the outside of foundations has been a problem for…