A pool structure is rarely visible when the pool is finished, but it affects almost everything you will appreciate in the years that follow: the bathing experience, energy consumption, installation time, and how easy the pool is to maintain. This guide to pool structure materials will help you choose a solution based on your plot, your level of ambition, and the Swedish climate - not just the purchase price.
For many homeowners, the pool is a long-term investment in family life, relaxation, and a more vibrant outdoor living space. That is why the structure should be chosen with the same care as the pool enclosure, water treatment, and heating. The right material can provide an easy-to-maintain pool with a stable temperature and durable construction. The wrong choice can mean compromises that only become noticeable after a few seasons.
What does the material in a pool structure do?
The pool structure is the pool's load-bearing construction. It must withstand the pressure of large amounts of water, movement in the ground, and variations between winter cold and summer heat. At the same time, the material determines which shapes, depths, and surface finishes are possible.
For an in-ground pool, the structure must also work together with the groundworks. Drainage, foundations, backfilling, and any groundwater level are at least as important as the pool model itself. A well-built structure is therefore part of a whole, not a stand-alone product.
The most common options for a permanent pool are PP and ThermoPP, thermo blocks or insulating blocks, fiberglass, and steel wall constructions with a liner. Each material has clear strengths, but suits different needs.
Guide to pool structure materials: four common choices
PP and ThermoPP - premium feel and welded tightness
PP pools are manufactured from durable plastic and are usually delivered as factory-welded basins. ThermoPP is based on the same principle, but with insulating materials in the construction, which can help reduce heat loss. For those who prioritize a modern, smooth pool environment and easy maintenance, this is a very attractive option.
The smooth surface has no joints that collect dirt in the same way as many other solutions. This makes everyday cleaning easier and gives the pool an exclusive look. PP is also well suited to those who want an integrated stair, seating bench, different depths, or a more architect-designed shape.
A PP pool often has a higher initial cost than simpler structures, and transport and lifting must be planned if the basin is delivered in one piece. On a tight plot, this can affect the choice of model and installation method. When the conditions are right, however, you get a highly durable and dimensionally stable pool with few surfaces to maintain.
Thermo block - flexible shape and good insulation
A thermo pool is usually built from insulating blocks that are reinforced and filled with concrete. The construction combines the stability of concrete with insulation around the basin. The result is a pool that can be adapted well to the plot, terrace, staircase, and desired dimensions.
This is a strong choice for anyone with a clear vision for the pool's design. Straight lines, corner stairs, unusual dimensions, and adaptation to level differences are often easier to solve with a block system than with a factory-made pool shell. The insulation is especially relevant in Sweden, where a long swimming season requires well-planned heating and reduced heat loss.
Thermoblock requires careful construction and the right expertise throughout the entire process. Concrete, reinforcement, and groundwork must be carried out correctly for the structure to achieve the expected stability. For many, a turnkey contract is a reassuring option, especially when the pool build needs to be coordinated with groundworks, electrical work, plumbing, and the pool enclosure.
Fiberglass - fast installation with a ready-made pool shell
A glasfiberpool is normally delivered as a pre-molded pool shell. Just like with PP, installation is often quick once the groundwork is complete, since the pool's shape and surface are already finished at the factory. The smooth interior creates an inviting swimming experience and makes it easy to keep clean.
Fiberglass is suitable for those who want a proven pool shape with a shorter build time on site. The models come in many sizes and with integrated stairs, making it easy to find a solution for both families with children and adults who want to combine exercise swimming with relaxation.
The limitation is primarily design freedom. You choose from available models rather than creating fully custom dimensions. Access to the plot also needs to be checked well in advance, since a finished pool shell may require a crane truck. On the right plot, however, fiberglass is an efficient way to get from planning to swimming more quickly.
Steel wall with liner - affordable and flexible solution
Steel wall pools are often an accessible option for those who want to build an in-ground pool with a liner. The structure is built from steel panels or steel walls and gets its watertight interior through a pool liner. The solution is common in round, oval, and rectangular designs alike.
A major advantage is that the liner can be replaced when it has reached the end of its service life. This makes it possible to refresh the pool's appearance without rebuilding the entire structure. A steel wall can also be a wise choice when the budget needs to be prioritized across several parts of the pool project, for example the pool enclosure, heat pump, and garden landscaping.
At the same time, you need to plan for future liner replacement. The liner's lifespan is affected by water chemistry, sun, usage, and maintenance. The construction must also be protected and installed according to the instructions in order to function long term in a damp ground environment.
Choose structure based on plot, use, and level of ambition
The best pool structure is rarely the one that is best on paper in every situation. On a flat and easily accessible plot, a finished pool shell in PP or fiberglass can be a rational choice. On a plot with level differences, limited access, or a desire for custom dimensions, a thermo pool may provide greater freedom.
Also consider how the pool will be used. A family with children may value a wide staircase, slip-resistant surfaces, and a shallower section for play. Anyone primarily wanting to swim for exercise instead needs to prioritize length, a straight swim line, and a depth suited to training. If you want to create a more relaxing environment, a bench seat, massage zone, and pool enclosure can be highly important for the overall experience.
The pool's location also affects the choice. Trees near the pool mean more leaves and pollen, making easy-to-clean surfaces especially valuable. An exposed, windy location increases the need for insulation and a well-fitted pool enclosure. The enclosure helps retain heat, reduce evaporation, and keep the water cleaner - regardless of which structural material you choose.
The Swedish climate places demands on more than the structure itself
Frost, ground frost, and periods of heavy rain are real conditions when building a pool in Sweden. That is why a durable result starts beneath the pool. A properly prepared base, functioning drainage, and correct backfilling reduce the risk of movement and problems over time.
Groundwater is a particularly important issue. If water can press against the pool from the outside, the construction and drainage need to be planned for that from the start. This applies to all materials, but is handled differently depending on pool type and ground conditions. A site assessment before requesting a quote provides a better basis for decisions than choosing a model based solely on pictures and dimensions.
The energy issue is just as practical. A well-insulated structure can contribute to an energy-efficient pool, but it does not replace a pool enclosure, a correctly sized heat pump, and good water care. It is the interaction between these parts that determines how comfortable the temperature will be and what operating costs during the swimming season.
Look at the total cost, not just the initial price
The purchase price of the pool structure is easy to compare. The real cost also includes groundworks, installation, insulation, backfilling, transport, electricity, treatment, heating, and future maintenance. A cheaper construction may be entirely right, but only if it matches the project's requirements and your expectations for lifespan.
Therefore, compare quotes at the same level. Check what is included in the pool package, whether stairs and lighting are included, which warranty applies, and how installation is handled. Also ask how service, spring opening, and winter shutdown can be managed once the pool is in place.
Pooltime works with several pool materials and can help assess which construction suits your project, from initial planning to completed installation. This makes it easier to weigh appearance, function, and future operation against each other before the decision is made.
Let pool life guide the choice
Think one step beyond the build day itself. Picture the first warm evening under the pool cover, children taking one last swim after school, and weekends when the garden becomes the family's natural meeting place. Choose the pool structure that gives the best conditions for exactly that life - with a construction that feels safe to own, easy to maintain, and built for many Swedish summers.
