Q: What is the R-value of a typical 8-inch-thick, cast-in-place, residential basement wall?

A.: The R-value of an uninsulated, 8-inch-thick basement wall built using normal-weight concrete is 1.35, based on data from the 1993 American Society of Heating, Refrigeration, and Air-Conditioning Engineers' Handbook. By doubling the thickness of the wall to 16 inches, the R-value only increases by 0.50.