What construction work will be required?

Before buying a spa, swimspa or pool, it is essential to understand the level of construction work each option involves. Installing a unit on a prepared slab is not the same as carrying out a full excavation with a reinforced concrete structure. The scale of the work directly affects budget, timelines, permits and technical complexity.

Before going deeper into the type of construction work required, it is also useful to review the before buying guide, where the technical and planning aspects that influence this type of project are explained.

In addition, even when dealing with a spa or swimspa, the construction work can be significant if it is partially or fully recessed. In these cases, it is not enough to simply “make a hole”: the structure must be properly built, drained and allow sufficient technical access for maintenance. Planning this phase well helps avoid extra costs and future problems.

Concrete Pools

The full excavation is carried out according to the dimensions and depth of the design, including beach areas, steps or benches if present. It is necessary to allow for over-excavation to accommodate the structure, drainage systems and possible retaining walls on sloped plots, as well as the proper removal and management of excavated soil.

Prefabricated Pools

The adapted excavation is tailored to the chosen monobloc shell and requires a perfectly levelled and compacted base. After placement with a crane, controlled lateral backfilling is carried out to ensure structural stability and prevent deformation of the shell.

Inground / partially inground spa or swimspa

The excavation must allow for technical perimeter access, include bottom drainage to prevent water accumulation, and leave sufficient space for future interventions. It cannot be executed as a hole fitted to the millimeter; it must be structurally finished, stable and accessible for maintenance.

Concrete Pools

The structure is built using steel reinforcement followed by shotcrete or poured concrete, forming the structural shell that will withstand the pressure of both the ground and the water. After curing, waterproofing and the chosen finishing system are applied to ensure watertightness and long-term durability.
If you want to understand in more detail how this type of shell is built and which waterproofing systems are used, you can consult the guide on concrete pools.

Prefabricated Pools

It requires a perfectly levelled and compacted base that distributes the loads evenly. Once the shell is placed, controlled lateral backfilling is essential to prevent movement or deformation and ensure structural stability.

Spa or swimspa

It requires a concrete slab sized for the full load, which can reach several tonnes when the structure and water are combined. The surface must be completely level to avoid stress on the shell and ensure the correct operation of pumps and internal systems.

The structural base requirements, crane access and technical planning are explained in more detail in the guide on swimspa installation.

Pools

In concrete pools, watertightness must be ensured by the structure itself, through properly executed concrete and dedicated waterproofing systems. Glass mosaic (gresite) or porcelain tiles are decorative and surface protection finishes, but they do not by themselves guarantee that the shell is watertight. In the case of liners or prefabricated pools, the membrane or the monobloc shell itself acts as the main watertight element.

Inground Spas and Swimspas

The excavation must be fully finished with side walls built in concrete, block or a stable metal structure. A drainage system is essential to prevent water accumulation from rain or seepage, as well as an accessible service opening that allows maintenance and future interventions without the need for demolition.

Hydraulic Installation

It includes supply, suction and drainage pipes, properly sized according to the flow rate and water volume. In pools, these lines connect to the filtration system and, if applicable, the heating system; in spas and swimspas they form part of the internal circuit of pumps and jets, although an accessible drain may be required for periodic emptying.

Pump Room

A pump room or ventilated compartment must be planned to house the pump, filter, electrical panel and any additional equipment. It should be accessible, protected from moisture and provide sufficient space for maintenance.

Electrical Installation

A dedicated electrical line from the main distribution board is required, with a circuit breaker and a 30 mA residual current device (RCD) in accordance with regulations. In swimspas, the required power and technical space are usually greater due to heaters and multiple pumps.

Concrete Pools

It involves a full structural build with excavation, steel reinforcement, concreting, waterproofing and finishing. The process usually takes several weeks, depending on the size, weather conditions and level of customization of the project.

Prefabricated Pools

Execution is faster, since the shell arrives finished from the factory, but it requires coordination with heavy machinery (crane) and proper prior preparation of the ground and support base.

Read our article on the advantages and disadvantages of concrete pools compared with prefabricated pools.

Above Ground Spa or Swimspa

It involves minimal construction work when a suitable base and utility connections are already in place. Installation can be completed in a few days if the technical preparation has been properly resolved.
If you want to see examples of real residential spa installations with a prepared technical base and proper maintenance access, you can visit Aqaspas.

In Ground Spa or Swimspa

It means an intermediate level of construction work, as it requires excavation, a perimeter structure, drainage and technical access. It also requires structural planning and consideration of future maintenance.

Key point: what matters is not only what is installed, but how the construction is prepared to ensure access, safety and long-term maintenance.