Swimming Pool Structural Design: Domestic and Commercial

A swimming pool is a structural water tank with specific loading and waterproofing requirements. Domestic infinity pools, commercial leisure pools, and competition pools all demand similar engineering disciplines.

Loading

• Water: 9.81 kN/m³ — significant for full pools
• Hydrostatic pressure on walls — varies with depth
• Empty pool buoyancy uplift — major for in-ground pools in high water table
• Surrounding ground pressures
• Thermal effects

Construction methods

Reinforced concrete

Most common. Designed water-tight (SANS 10100-1) with controlled crack widths. Typical wall 250–400mm thick depending on depth.

Pre-cast concrete

Factory-made shell installed on prepared base. Faster but limited to standard sizes.

Liner-on-block

Block walls with vinyl liner. Cheaper but less durable than RC.

GRP shells

Pre-formed glass-reinforced plastic — domestic only.

Waterproofing

• Type B (waterproof concrete) for RC pools
• Tile-on-screed with sealed expansion joints
• Vinyl liner for liner-construction
• External tanking for indoor pools to manage condensation

Empty pool risk

Critical: an empty pool with high water table can float out of ground. Solutions:

• Sufficient self-weight
• Anchor base to pile or anchor block
• De-watering before maintenance
• Never empty without engineer review

Plant room

Pumps, filters, chemicals, heat exchangers. Sized for pool volume. Usually below or adjacent. Drainage, ventilation, and chemical containment critical.

Indoor pool considerations

• Humidity-driven structural degradation
• Aggressive atmosphere — stainless fixings required
• Roof and ceiling materials carefully chosen
• Ventilation system more critical than heating

Cost

• Domestic in-ground RC pool: R900,000–R2,400,000+
• Domestic liner pool: R500,000–R1,400,000
• Commercial leisure pool: R8,000–R16,000 per m² of water area

MCFAR engineers structural shells for residential and commercial pools.

Frequently Asked Questions