I work for a Commercial pool builder. We are doing a Jr. Olympic pool (competition pool) 40 ft by 70 ft (12 m by 21 m) with a 20 ft by 10 ft (6 m by 3 m) swim out area with steps. I would rather have the entire pool shot with shotcrete. The office wants the floor poured first then shoot the walls the next day. Can you talk about any advantages or disadvantages to either? Normally we are in a remote location with no power or water. We’ve had issues with shotcrete cracking on the floors and I understand that can happen because of many factors but poured concrete can as well.

Casting the floor first is recommended. Note that rebound and trimmings from vertical wall placement are not fully consolidated concrete and must not be used as part of a structural concrete section. Thus, casting first allows:

• No collection of rebound and trimmings from wall construction to get trapped below floor reinforcing steel.
• Provides a stable surface to collect and remove rebound and trimmings.
• Is generally faster placement and allows full consolidation of concrete throughout the floor thickness by immersion vibrators.
• If using wet-mix shotcrete the shotcrete pump can serve as a line pump for pumping concrete into the floor thus requiring no extra equipment.
• Allows proper joint preparation at the floor/wall joint to provide a watertight joint.