Pool Built-In Components by Pool Type: Liner, Concrete, Prefabricated
Whether skimmer, inlet nozzle, main drain or lighting: the pool built-in components must match the pool type exactly, otherwise leaks, dead zones and costly rework are the result. Choosing the right built-in components to suit the pool type is therefore one of the central planning decisions in swimming pool construction – and it works out differently for a liner pool than for a concrete pool or a prefabricated GRP pool. This guide is aimed at specialist contractors, planners and demanding pool builders, and systematically assigns designs, materials and connection sets to the respective pool.
What counts as pool built-in components?
Built-in components are all the components of the water circuit and the equipment that are fixed permanently into the pool wall or pool floor. They form the interface between the pool shell and the pipework and are immersed in water throughout the entire service life of the installation – the requirements for water-tightness and durability are correspondingly high. The most important groups include:
- Skimmers (surface suction devices): draw off the near-surface water together with leaves, pollen and suspended matter.
- Inlet nozzles: return the cleaned water and ensure an even through-flow.
- Main drains (bottom outlets): extract water from the deepest zone of the pool and are used for basic draining.
- Wall suction connections: connection point for the pool cleaner or manual pool cleaning.
- Underwater floodlights and niches: lighting components for wall or floor mounting.
- Massage and counter-current nozzles: optional comfort components for wellness and training.
What they all have in common is that the connection to the pool wall depends on the pool type. This is precisely where it is decided whether a built-in component stays permanently water-tight.
Why the pool type determines the choice of built-in components
The structural build-up of the pool wall determines how a built-in component is fixed and sealed. In simplified terms, three construction methods can be distinguished, each requiring its own connection logic:
- Liner pools: thin, flexible inner shell (liner) – sealed by flange, counter-flange and flat gasket, which clamp the liner.
- Concrete pools: solid, rigid structure – built-in components are cast into the concrete or plastered in and held by the bond to the concrete.
- Prefabricated pools (GRP/polyester) and steel-wall pools: thin, rigid wall – built-in components are bolted stress-free to the low wall thickness using matched connection sets.
A built-in component intended for concrete generally cannot be connected cleanly to a liner – and vice versa. The choice of material is equally relevant to safety: all built-in components must be permanently resistant to UV, chlorine and – with salt electrolysis – salt water. The planning framework is set by standards such as DIN EN 16582 (requirements for private swimming pools) and DIN EN 16713 (water circulation and recirculation); for public pools, DIN 19643 is authoritative.
Pool built-in components by pool type in detail
The three pool types are described below with their respective requirements for the built-in components. The order corresponds to their frequency in private and semi-public construction.
Liner pools
In a liner pool, a flexible inner shell lines the structure. Every built-in component must clamp the liner in place and at the same time seal it permanently. This is achieved with a flange set consisting of a built-in body, counter-flange (trim plate) and one or two flat gaskets. Decisive for water-tightness are a flat contact surface, clean, crease-free liner in the clamping area and even, cross-pattern bolting. Skimmers, inlet nozzles, main drains and floodlight niches are all designed in this flange construction. The widely used standard material is ABS; with salt water, expressly approved versions must be used.
Concrete pools
In a brick-built or concrete pool, the built-in components are cast into the concrete or plastered in. Robust versions with a good bond to the structure are required. Extended skimmer necks, plaster-in rings or tile frames make it easier to achieve a flush finish with plaster, tile or liner-on-concrete lining. Since subsequent corrections in concrete are laborious, precise positioning and plumb or level installation before concreting are particularly important. Concrete pools offer the greatest freedom in design and material – from high-quality plastic to stainless steel built-in components for design pools.
Prefabricated pools (GRP/polyester) and steel-wall pools
Prefabricated pools made of glass-fibre-reinforced plastic and steel-wall pools have a thin but rigid wall. Here a suitable connection set is decisive, one that bridges the low wall thickness stress-free. Matched gaskets and defined tightening torques prevent cracks in the GRP or damage to the coating. The openings are often already provided at the factory; the built-in components must then match the hole pattern and wall thickness exactly. With steel-wall pools, special lead-through sets with gaskets on both sides provide reliable sealing of the wall opening.
| Pool type | Connection principle | Critical point | Typical material |
|---|---|---|---|
| Liner pool | flange + counter-flange + flat gasket (liner clamped) | flat contact surface, crease-free liner, cross-pattern bolting | ABS (standard) |
| Concrete pool | cast into concrete / plastered in, bond to the structure | exact position before concreting, flush finish | ABS, PP, stainless steel |
| Prefabricated pool (GRP) | connection set for thin wall, defined tightening torques | stress-free installation, matching hole pattern | ABS, PP |
| Steel-wall pool | lead-through set with gaskets on both sides | sealing of the wall opening, corrosion protection | ABS, PP |
Materials: ABS, PP and stainless steel compared
The material determines longevity, appearance and suitability for certain water treatment methods. In practice, three materials dominate – regardless of the pool type:
- ABS (acrylonitrile butadiene styrene): impact-resistant, dimensionally stable, good surface quality. The widely used standard for high-quality plastic built-in components.
- PP (polypropylene): particularly resistant to chemicals and temperature, often used for weldable built-in components in PP pools.
- Stainless steel (V2A / V4A): high-quality, long-lasting appearance for design pools and public pools. V4A (1.4571) is significantly more corrosion-resistant than V2A (1.4301) and is the first choice for salt-water and brine pools.
| Material | Chlorine resistance | Salt-water suitability | Typical use |
|---|---|---|---|
| ABS | good | conditional | liner, concrete and prefabricated pools (standard) |
| PP | very good | good | PP pools, weldable versions |
| Stainless steel V2A | very good | conditional | fresh-water design pools |
| Stainless steel V4A | very good | very good | salt/brine pools, public pools |
A frequently underestimated point: within a single installation, the materials should be matched to one another. If, for example, stainless steel trim plates are combined with baser metal parts, contact corrosion can occur. For salt-water pools, the principle is to use salt-water-suitable plastics or V4A consistently.
Sizing: number and arrangement of the built-in components
Besides selecting components to suit the pool type, the hydraulic sizing determines water quality. The central figure is the turnover rate: in the private sector, the entire pool water should be turned over about every 3 to 4 hours; public pools are subject to the stricter requirements of DIN 19643. The circulation capacity determines how many skimmers and nozzles are required and how they are to be distributed.
Rule-of-thumb values for private pools are: one skimmer per around 25 to 30 m² of water surface and one inlet nozzle per around 25 to 30 m³ of pool volume. Skimmers and inlet nozzles should be arranged opposite one another where possible, so that a directed surface flow is created and no dead zones remain. The prevailing wind direction must be taken into account here, because it drives the surface dirt towards the skimmers.
| Pool size | Skimmers (guide value) | Inlet nozzles (guide value) | Main drain |
|---|---|---|---|
| up to approx. 30 m² | 1 | 2 | 1 (recommended) |
| approx. 30–60 m² | 2 | 2–4 | 1–2 |
| over 60 m² | 3 or more | 4 or more | 2 or more |
Note: The values are planning guide values. The binding sizing is carried out on a project-specific basis using the pump characteristic curve, pipe network and filter technology. With main drains, the safety-related requirements for protection against suction entrapment must also be observed – when in doubt, two separate suction points should be provided.
Typical mistakes in selection and installation
- Built-in component and pool type not matched: a part intended for concrete cannot be connected cleanly to a liner. Always choose to suit the pool type.
- Wrong material for salt water: ABS in a basic version or V2A in salt-electrolysis pools deteriorate over the long term – salt-water-suitable plastics or V4A belong here.
- Gaskets fitted incorrectly: swapped or pinched flat gaskets and unevenly tightened bolts are one of the most common causes of leakage – especially at the liner flange.
- Position and height disregarded: the skimmer neck must match the operating water level; incorrectly placed nozzles create dead zones.
- Pipework undersized: nominal sizes that are too small throttle performance and put strain on the pump.
- Tightening torques exceeded on GRP: over-tightening on thin prefabricated pool walls can cause cracks.
Careful installation pays off over the entire service life of the installation. Before compressing the gasket, always check the flatness of the contact surface, tighten bolted connections in a cross pattern and in several passes, and document the connection dimensions and nominal sizes used. This way, every built-in component remains clearly identifiable even when spare parts are later required.
Compatibility and spare parts: what specialist contractors watch out for
With existing installations in particular, the compatibility of the built-in components is a frequent topic. Connection geometry (nominal size and thread of the pipe, often 1½″ / 2″ female thread), the hole pattern of flange and trim plate, and gasket dimensions must all match. Anyone who opts for a consistent, mutually matched programme from a single manufacturer for new construction and refurbishment reduces interface problems and ensures long-term spare-parts availability. Documented connection dimensions make it easier to replace individual components later without having to open the liner or the pool shell.
Conclusion
Selecting pool built-in components by pool type means: first clarify the construction method of the pool wall – liner, concrete or prefabricated pool –, then match the connection set, material and design to it, and finally size the number and arrangement correctly in hydraulic terms. Anyone who works through these levels – geometry, material and sizing – systematically obtains a permanently water-tight, well-flushed installation with minimal operating effort. In the range of Peraqua swimming pool technology, specialist contractors will find matched built-in components for every pool type – from skimmers and inlet nozzles to main drains and lighting.
Frequently Asked Questions
Which pool built-in components form the basic equipment?
The basic equipment of a pool includes skimmers for surface suction, inlet nozzles for water return and, as a rule, a main drain for the deepest zone and basic draining. Depending on the installation, these are supplemented by a wall suction connection for pool cleaning, underwater floodlights and optional massage or counter-current nozzles. All built-in components must match the respective pool type and the water treatment.
How do built-in components for liner, concrete and prefabricated pools differ?
In a liner pool, the built-in components are connected to the inner liner by clamping via flange, counter-flange and flat gasket. In a concrete pool, they are cast into the concrete or plastered in and held by the bond to the structure. Prefabricated pools made of GRP and steel-wall pools require a connection set that bridges the thin wall stress-free. The pool type therefore determines the flange, gasket and fixing method.
Which material is suitable for salt-water pools?
With salt-electrolysis installations, ABS in a basic version or stainless steel V2A (1.4301) are at risk over the long term. Salt-water-suitable plastics or stainless steel V4A (1.4571), which is significantly more corrosion-resistant, are recommended. Within the installation, the materials should be matched to avoid contact corrosion. When selecting, pay attention to the manufacturer’s salt-water approval.
How many skimmers and nozzles does my pool need?
As a planning guide value for private pools, allow about one skimmer per 25 to 30 square metres of water surface and one inlet nozzle per around 25 to 30 cubic metres of pool volume. Skimmers and nozzles are arranged opposite one another where possible, so that a directed flow is created and no dead zones remain. The binding sizing is project-specific, based on turnover rate, pump characteristic curve and pipe network; privately, the water should be turned over about once every 3 to 4 hours.
Can existing built-in components be reused during a refurbishment?
That depends on their condition and compatibility. If the connection geometry, hole pattern and gasket dimensions match, individual components can often be replaced without opening the liner or pool shell. With porous plastics, hardened gaskets or materials that do not suit the current water treatment, replacement is advisable. Documented connection dimensions make it considerably easier to select suitable spare parts.
