Abstract | A $12.8 million Conference Center constructed in 1995 showed evidence of pronounced cosmetic and functional distress shortly after construction that raised questions about the overall structural integrity of the building. Detailed structural and geotechnical forensic investigations conducted by the writers determined the cause of the distress to be the expansion of electric arc furnace slag used as a subgrade material beneath column and wall foundations and the slab-on-grade. Specialized confined swell tests demonstrated the ability of the slag to exert uplift pressures in excess of five (5) kips per square foot (ksf). Rehabilitation of the conference center was achieved by underpinning all column and wall foundations in the affected areas, removing the slag from beneath these foundations, and replacing the slag with flowable backfill.