Which foundation statement correctly identifies acceptable foundation elements for tilt-up construction?

• A. Shallow footings, drilled piers, pad footings, continuous footings, grade beams, and stem walls are acceptable; rafts or mat slabs cannot be used.
• B. Rafts or mat slabs are acceptable.
• C. Only raft slabs are acceptable.
• D. No foundations allowed.

Answer: (C)

In tilt-up construction the foundation needs a single, continuous bearing surface that keeps the wall panels and slab level and evenly loaded during erection and in service. A raft slab (mat foundation) provides that by spanning the entire footprint with reinforced concrete, distributing loads from all walls across a wide area and minimizing differential settlement. This creates a stable, flat base for erecting and tying together the tilt-up elements, which is why raft slabs are the acceptable foundation choice. Other footing types—discrete footings, pad footings, grade beams, or stem walls—can create uneven bearing and potential misalignment or differential settlement, making them unsuitable as the standard foundation in tilt-up practice.