Types of swimming pools: which pool type works where?

A reinforced concrete pool is built on site. Size, shape and depth are set entirely by the design; freeform shapes, beach entries, seating ledges and infinity edges are built this way. It has the longest time on site and the widest design freedom of any system. When deciding between a reinforced concrete and a prefabricated pool, ground conditions, access and timescale are assessed together.

In a prefabricated panel pool, steel or composite panels are assembled on site and the interior is finished with a liner. It allows some flexibility in size, has a short time on site and needs no crane. Panel systems are also used at commercial scale; 25-metre semi-Olympic pools can be built this way. We explain the difference between panel and fibreglass prefabricated systems in detail in our prefabricated pool guide.

Fibreglass and polyester pools come out of a one-piece mould; no shell is built on site, only the excavation, base slab and plumbing. It is the system with the shortest time on site, and its jointless surface makes cleaning easier. On the other hand, size and shape are limited to the mould dimensions, and access for a lorry and crane is essential. In our article comparing ready-made, fibreglass and polyester pools, we set out in a table when each of the three is chosen.

In a one-piece pool, the depth also comes with the mould. In our article on depth flexibility in ready-made pools, we set out separately which systems allow the depth to be changed and which do not.

A skimmer pool needs no extra tank, so the plant room stays small. Most residential pools are built with this system. The skimmer opening is usually placed on the edge towards which the wind pushes leaves; one skimmer serves an average of 25-35 square metres of surface. We cover the difference between skimmer and overflow systems in terms of budget and water quality in a separate article.

In an overflow pool, the water spilling along the perimeter collects in a balance tank and goes from there to the filter. The surface cleans itself and the waterline looks unbroken. A balance tank, an overflow channel and a larger pump are needed. This system is preferred for heavily used hotel, residential complex and competition pools.

An infinity pool is the overflow system applied on one or two edges for visual effect; no coping is visible on the edge where the water spills over. A difference in ground level is needed for the effect to work. How an infinity pool works is the subject of a separate article; the items an infinity pool adds are also listed one by one in our cost article. By keeping skimmers on the other edges, a similar look can be achieved on a more moderate budget.

The outdoor pool is the most common type and is used seasonally. With a heat pump the season extends into April and October; a cover reduces both heat loss and evaporation loss. It is not drained in winter; the water level is lowered and the pool is winterised.

With an indoor pool the real issue is not the water but the air. Moisture evaporating from the pool surface condenses on cold surfaces and wears down the ceiling and steel components. Air temperature is kept 1-2 degrees above the water temperature, and relative humidity in the 50-60 percent range. We explain humidity and ventilation calculations for indoor pools with figures in a separate article.

For terrace and rooftop pools, structure is the deciding factor. A water depth of 1.2 metres means a load of 1.2 tonnes per square metre; finishes, the shell and user loads are added to this. The load of a terrace or rooftop pool is checked by structural calculation, and the load-bearing system is strengthened where necessary. Here the waterproofing is applied in two layers, as a second layer of protection for the space below.

Residential pools cluster around 4x8 and 5x10 metres; a constant depth of 1.40-1.50 metres is the most popular layout. For families with children, a separate children's section, or one divided off by a step, is planned. We give pool size selection by garden, together with volume calculations, in our article on sizes and depths.

In residential complexes and apartment blocks the number of users is high and variable. Turnover time is kept shorter than for a private pool, and automation with automatic dosing and record keeping is necessary. In hotel and commercial pools, an overflow system, high turnover capacity and a redundant pump are standard; a second line is installed so that the pool does not have to close when a pump fails. Competition pools are subject to separate rules on dimensions, depth, lanes and timing equipment.

A natural pool may seem like a world of its own, but the construction logic is the same: shell, waterproofing, circulation. The difference lies in the treatment. In our article on natural ponds with biological filtration, we explain how the swimming zone and the treatment zone are separated.

We recommend positioning the pool in relation to the house, not the view. A pool that cannot be seen from the living room and kitchen gets little use after the first summer, and supervision becomes harder. The direction of the afternoon sun, the edge towards which the wind pushes leaves and the distance from the plant room to the pool determine the position.

In a flat garden, moving part of the budget that would go into an overflow system to the surrounding paving, lighting and landscaping often gives a more visible result. Adding a raised hot tub beside the pool is one of the most requested layouts on villa projects. The condition is separate circulation: since the hot tub runs at 36-38 degrees and the pool at 26-28 degrees, a separate pump, heater and filter are needed.

The most concrete advantage of a small pool is its low water volume. A 3x6 metre pool with a depth of 1.40 metres holds about 25 cubic metres, a third of a 5x10 metre pool. It heats quickly, needs few chemicals and is quick to maintain. The difference is felt in running costs every month.

A one-piece polyester or fibreglass pool is also considered for a small garden, but first we check whether the crane arm can reach the garden. In terraced houses and narrow streets, crane access often makes a reinforced concrete or panel system the only option.

A swim spa allows stationary swimming against a counter-current in a 4-6 metre body, and because it is heated it can be used in winter too. It may not satisfy someone who expects a classic pool; we discuss this at the outset.

At the survey we check the slope of the plot, the soil class, groundwater, crane and lorry access, and the electricity and water connections. These data sometimes change the chosen type: a one-piece pool is not possible in a garden with narrow access, and on a plot with high groundwater we recommend a reinforced concrete shell instead of a panel system. Our guide to having a pool built, from survey to handover, describes each of these steps with its duration and responsibilities.

In our pool construction service, we finalise the type decision after the survey, once we have seen the site. A decision made from a catalogue or gallery often changes on site; seeing this already at the survey saves both time and budget.