Swimming Pool Construction Stages: From Design to Filling

The sequence of building a garden pool: early decisions, design, excavation, structure, pipework, waterproofing, finishes and first start-up.

A pool may look like a simple hole in the garden, but it is really a combination of several engineering systems: a watertight structure, filtration and circulation, electrics, drainage and the surrounding area. A mistake at any stage hides inside the stages that follow, and many problems only appear once the pool is full of water. When owners understand the order of works, they know what to check before each next step.

1. Early decisions

Construction starts with a question, not a digger: what is the pool for? Playing with children, swimming for exercise, cooling off or a decorative centrepiece in the landscape all call for different sizes, depths and shapes. This is also when you decide whether the pool will be outdoor or indoor, which months it will be used and whether the water will be heated.

The location is chosen with sun, wind, trees, distance from the house, underground services and the plant room position in mind. Access for construction machinery into the garden should also be checked early. How the pool will relate to the house in future, for example where an outdoor shower, changing area or summer kitchen will go, is also considered now, since their water and drainage lines can run alongside the pool services.

2. Design and ground investigation

At the design stage, the shell structure, reinforcement layout, pipework and equipment diagram, electrics and earthing, drainage and the pool surround are prepared. Information on soil type and groundwater level is essential for the structural decision: high groundwater, risk of ground movement or made ground require additional measures.

The type of pool is also chosen now: cast concrete, a prefabricated composite shell or another system. Each has a different construction sequence. The steps below apply to the most common type, the concrete pool.

3. Excavation and base

The excavation is made slightly larger than the design dimensions to leave room for formwork, waterproofing and pipework. The sides of the pit are protected against collapse according to the soil type. At the bottom, a compacted base, a drainage layer where needed and a concrete blinding layer are laid.

Where the excavated soil will be stored or taken should be planned in advance, as there is usually more of it than expected.

4. Structure, pipework and equipment

The reinforcement cage is built and the items cast into the concrete are fixed precisely in place: skimmers or an overflow channel, return inlets, main drains, light niches and step fixings. Their positions cannot be changed after the pour, so they are checked before the concrete goes in. The check confirms that return inlets will spread circulation evenly across the shell and that lights face a direction that will not shine into swimmers’ eyes.

Concrete of the grade specified in the design is poured as continuously as possible, and then a curing period is allowed for it to gain strength. Keeping the concrete moist during this time helps prevent cracking.

Pipes from the shell to the plant room are laid and pressure-tested before backfilling. Finding a leaking joint underground is very difficult, so this test is essential. In the plant room, the pump, filter, disinfection and heating equipment are installed, along with the electrical panel and earthing.

5. Waterproofing, finishes and start-up

The shell surface is prepared, waterproofing layers are applied, and the pool is filled with water before finishing so that the level can be monitored. Once it is confirmed there is no leak, the water is drained and finishing begins: mosaic, tiles or a liner. In parallel, the surround paving, railings and landscaping are carried out.

In the final stage the pool is filled, the equipment is commissioned, the water chemistry is balanced and the owner is shown how to operate everything. That handover directly determines the pool’s lifespan and water quality.

Questions to ask at each stage

• Is there information on soil and groundwater?
• Were embedded items checked before the concrete pour?
• Have the pipes passed a pressure test?
• Was a water test carried out before finishing?
• Has an operating guide for the equipment been provided?

Zaferoğlu İnşaat works in construction, design and architectural planning and presents garden and landscape solutions with computer models. Planning a pool? Talk to us before the digging starts.