Subsection R506.3 is hereby added to the International Residential Code for One- and Two-Family Dwellings and shall read as follows:

R506.3 Basement floor slab isolation. Basement floor slabs shall be isolated from column pads, interior columns and interior bearing walls to facilitate differential movement. Nonbearing walls supported on basement floor slabs shall be provided with a minimum one inch (1") expansion joint to facilitate differential movement between the floor slab and the floor framing above. Isolation and/or an expansion joint is not required within six inches (6") of the exterior walls.