Subsection R402.2.9.1 is hereby added to the International Energy Conservation Code and shall read as follows:

R402.2.9.1 Concrete and masonry basement walls. Insulation is not required for concrete or masonry portions of basement walls of one- and two-family dwellings which are not adjacent to nor form a common wall with finished space and are more than 50 percent (50%) below grade. Such common walls shall be insulated whenever the adjacent interior space is finished.