What is the minimum SOG thickness recommended for tilt-up projects?

• A. 3"
• B. 4"
• C. 5"
• D. 6"

Answer: (C)

Slab-on-grade thickness in tilt-up work is chosen to ensure the base can safely transfer loads from the wall panels and accommodate necessary reinforcement and joint details. The five-inch minimum is recommended because it provides enough depth to place reinforcing steel and dowels for panel-to-slab connections, gives adequate mass to resist cracking and curling from shrinkage, and offers sufficient bearing and stiffness to distribute loads without excessive deflection. A thinner slab (three or four inches) can underwhelm the load path and make it harder to embed anchors and control joints, while a much thicker slab (six inches) adds cost without typical benefit for standard tilt-up loads. Always align with project specs and local practices, but five inches is the standard baseline for reliable performance.