Concrete, fibreglass, steel, wood – the range of materials used in pool construction is wider than it appears. Each has legitimate applications. But when the project involves complex hydraulics, an overflow edge, or a custom structural form, the material choice is no longer a matter of preference. It is a technical constraint.
Understanding what each material can and cannot do is the starting point for any serious pool project.
What material is a swimming pool made of?
Most pools are built from one of four materials: reinforced concrete, fibreglass, stainless steel, or wood. Each produces a structurally sound basin under the right conditions – but their technical properties differ significantly.
Reinforced concrete is the most widely used material for in-ground pools worldwide. It can be formed into any shape, accommodates any hydraulic configuration, and accepts all finishing systems – tiles, plaster, exposed aggregate, or stone.
Fibreglass shells are factory-moulded and delivered to site as a single unit. Installation is fast, but shape and size options are limited to standard manufacturer moulds.
Stainless steel pools are prefabricated and assembled on site. They are used primarily for deck-level or lap pool configurations where a clean, contemporary finish is the priority.
Wood is used for above-ground or semi-inground installations. It is a natural, aesthetically warm material but requires a liner for waterproofing and has limited structural applications.
Why concrete is the only viable option for custom overflow pools
An overflow pool, infinity edge, zero-edge, deck-level or knife edge, is not a standard basin with a different aesthetic. It is a hydraulic system. The structure must integrate a continuous overflow channel, an embedded pipe network, floor-mounted return inlets, and a balancing tank. Every element is cast into or attached to the shell.
No other material accommodates this level of integration. Fibreglass shells are moulded to fixed dimensions – there is no provision for custom overflow channels or embedded hydraulics. Stainless steel panels are assembled from prefabricated components that cannot be adapted to bespoke overflow geometries. Wood is structurally unsuitable for the loads and waterproofing requirements involved.
Reinforced concrete is formed on site, around the hydraulic network. The pipe runs, inlet positions, overflow channel dimensions and structural reinforcement are all designed together and poured as a single integrated whole. This is what makes complex pool forms possible – and what makes overflow pools buildable at all.
Concrete shuttering blocks are one proven method for building reinforced concrete pools — including infinity pools. See our guide to building with shuttering blocks.
Durability and long-term performance
Reinforced concrete, correctly designed and waterproofed, has an indefinite structural lifespan. The shell does not degrade – what requires periodic attention is the surface finish, whether tiles, plaster or stone, and the waterproofing membrane at joints and penetrations.
Fibreglass shells require gel coat restoration after 10 to 15 years. The shell itself may last longer, but the surface degrades before the structure does. Stainless steel is highly durable but susceptible to corrosion in aggressive water chemistry conditions. Wood requires regular treatment and has the shortest lifespan of the four materials.
For a pool designed to last without structural intervention, reinforced concrete is the only material where longevity is not a variable – it is a given. A complete overview of how an infinity pool is built with this method – from excavation to commissioning – is available in our infinity pool construction guide.”
Morana's advice
The material choice is made once, at the start of the project. For an infinity pool, it is not a decision – reinforced concrete is the only structure that allows the hydraulic system, the overflow channel and the pool form to be designed and built as a single integrated whole. Everything else is a compromise.
Conclusion
Swimming pool construction materials are not interchangeable. Each has a context where it performs well – and a point where its limitations become structural. For overflow and infinity pools, reinforced concrete is not the premium option. It is the only option that makes the design buildable.
For projects involving custom pool forms and precision hydraulic design, see our infinity pool construction plans.
Frequently Asked Questions – Swimming Pool Construction Materials
What are swimming pools made of?
Most in-ground pools are built from reinforced concrete. Fiberglass shells, stainless steel panels and wood are also used, each suited to specific project types and budgets. For overflow and infinity pools, reinforced concrete is the only material that accommodates the hydraulic integration and structural complexity these designs require.
Which pool construction material is the most durable?
Reinforced concrete has an indefinite structural lifespan when correctly designed and waterproofed. Fiberglass shells require surface restoration after 15 to 20 years. Stainless steel is durable but sensitive to water chemistry. Wood has the shortest lifespan and requires the most ongoing maintenance.
Can a fiberglass pool have an infinity edge?
No. Fiberglass shells are factory-moulded to fixed dimensions and cannot be adapted to incorporate a custom overflow channel or embedded hydraulic network. An infinity edge requires a structure that is formed on site around the hydraulic system — which is only possible with reinforced concrete.