The stages of building a pool
A pool is built in seven stages: design and permit, setting out and excavation, embedded pipework and the shell, waterproofing and a water test, interior finish, the plant room, and filling and start-up. The concrete shell goes up quickly and looks like an almost finished pool, but much of the time and most of the risk come after it.
Below, in order: what happens at each stage, what the owner should check, and where a mistake costs the most.
Design and permit
The pool’s position is chosen by sun, wind, tree roots and distance to the boundaries. Minimum setbacks and the type of permit are set by planning rules and should be confirmed with the Ajuntament before the design is drawn up. On a sloping plot, the shell walls are calculated by an engineer, because they act as retaining walls.
At the same stage you decide where the plant room goes and where backwash water from the filter is discharged. If the pool is built together with the house, all of this belongs in a single design. How to plan house, pool and garden as one is covered in a separate guide.
Setting out and excavation
The digger needs access. On a plot in the Garraf hills with a narrow lane, that is a question in itself, sometimes solved with smaller machinery and a slower dig. The spoil has to go somewhere, and removing it is a budget line people often forget.
Excavation reveals what is underneath: rock, made ground or water. That is why the pool is best built before the garden is landscaped, not after. If the hole is dug next to a finished lawn and paths, putting them back comes out of your budget.
Embedded pipework and the shell
Before any concrete goes in, everything that cannot be added later is fixed into the reinforcement: skimmers or an overflow channel, return inlets, the main drain, light niches and the pipes to the plant room. An infinity-edge pool is more complex: it needs a balance tank and an edge level that is exact along its whole length.
Pipes are pressure-tested before the pour. The reinforcement is inspected by a technician before the concrete, not after. The shell itself is either sprayed concrete (gunite) or poured into formwork. The concrete is given the curing time the method requires; waterproofing over concrete that is too fresh is a common source of trouble.
Waterproofing and the water test
The shell is protected with a flexible cementitious membrane under the tiles, or with a reinforced PVC liner that doubles as the finish. The pool is then filled and left for several days while the level is monitored, with a correction for evaporation.
This test happens before the mosaic goes on. The most expensive mistake at this stage is tiling, filling, and only then finding the level dropping. Looking for a leak under finished mosaic means taking it off.
Interior finish and plant room
Shells are finished with glass mosaic, porcelain tile, reinforced liner or, less often, microcement, which needs very careful workmanship. Coping stones and the pool surround must be slip-resistant when wet.
The plant room is somewhere you will be going for years. It houses the pump, the filter, the salt chlorinator and, if the pool is heated, a heat pump. It needs ventilation, a floor drain in case of a leak, easy access and some distance from the bedrooms, because the pump makes noise. A pump works more easily when it sits below or close to water level; otherwise you need a self-priming model. If the house has solar panels, as in our 2022–2024 project, pool heating is sized together with what they produce.
Filling and start-up
Catalonia has restricted filling pools during drought periods. Check the current rules with the town hall and the water company before your filling date. Sometimes the water arrives by tanker.
The first weeks after start-up go on balancing the water chemistry, the filtration cycles and the equipment. At handover you should receive a pipework diagram, the equipment manuals and photos of the embedded pipes taken before the concrete pour. Requirements for fencing or a safety cover, especially with children in the house, are checked before the design, not after start-up.
Next step
We delivered a family house with a pool from start to finish between 2022 and 2024, from the design to the solar panels. If you are building a house or want to add a pool to the one you have, send us the site plan, photos, the pool size you have in mind and whether you want it heated. We reply within an hour, work in Russian and Spanish, and payments follow the stages set in the contract.