An indoor swimming pool is a serious investment. But the technical decisions – heating, ventilation, waterproofing – are only half the story. The other half is design, and it’s the part that determines whether the finished space feels like a genuine extension of your home or something that never quite works.
We’ve already written about what an indoor pool involves technically. This guide is about something different: the design thinking that turns a technically sound indoor pool into a space you’ll want to spend time in every day, not just occasionally swim in.
Start With How You Want the Space to Feel
Before any decisions are made about materials, finishes, or features, it’s worth asking a more fundamental question. How do you want the space to feel?
An indoor pool can be many things. It can be calm and spa-like, designed around rest and recovery. It can be energetic and functional, built for regular lap swimming and exercise. It can be social, with space for entertaining and gathering. Or it can be architectural, a statement space that makes the most of a remarkable building or setting.
None of these is the wrong answer. But trying to make an indoor pool be all of them at once is usually where design goes wrong. The most successful indoor pool spaces have a clear character, and every decision from the pool shell to the lighting reinforces rather than contradicts it.
Natural Light Is the Single Most Transformative Design Decision
An indoor pool that feels alive and welcoming almost always has good natural light. One that feels institutional or oppressive almost always lacks it.
Roof lights and skylights are the most effective way to bring daylight into a pool hall. They introduce light from above, which washes down over the water in a way that side glazing alone rarely matches. The play of natural light on pool water is one of the most beautiful effects in any interior space, and it changes throughout the day in a way that no artificial lighting can replicate.
Side glazing, sliding doors, and full-width glazed openings to a terrace or garden extend the visual connection between the pool and the outside world. Even when the pool is enclosed, a strong glazed connection to the landscape stops it feeling sealed off. In a well-designed pool building, the indoor and outdoor feel like parts of the same space rather than separate environments.
Glazing in a pool hall needs to be specified carefully, triple glazing with thermally broken frames is the standard for performance, but the design opportunity it creates is worth every bit of the attention it demands.
The Pool Shell Sets the Tone
The pool itself is the centrepiece of the space, and its finish does more to establish the character of the room than almost anything else.
Dark shell finishes, deep charcoals, slate blues, and near-blacks, create depth and drama. The water appears darker, richer, and more opaque, which reads as luxurious and spa-like. Light finishes, creams, whites, and pale blues, create a brighter, more open feel. The water appears vivid and clear, which suits a more active, family-oriented pool environment.
Mosaic tile interiors offer the greatest design flexibility. Custom colours, patterns, and gradients are all achievable, and a skilled mosaic installation at the waterline or across the full pool floor creates a level of craft that is immediately apparent. The Petham Project, one of our most celebrated indoor builds and currently shortlisted for the 2026 European Pool & Spa Awards, features Waterford cream porcelain tiles that continue seamlessly from the pool interior onto the surrounding surfaces, tying the space together beautifully.
Poolside Surfaces and the Wet Environment
Every material in an indoor pool hall is living in a demanding environment. Humidity is constant, chemical exposure is ongoing, and surfaces are regularly wet underfoot. This has to be the starting point for every material decision.
Natural stone, large format porcelain, and specialist pool deck materials all work well when properly specified. The key considerations are slip resistance, particularly on surfaces adjacent to the pool edge, resistance to chlorine and other pool chemicals, and how the material handles prolonged exposure to moisture without deteriorating.
Colour and tone matter here too. Warm stone tones, creams, and sandy naturals tend to make a pool space feel relaxed and inviting. Cooler greys and blacks create a more contemporary, architectural feel. Neither is wrong, but the choice should be deliberate and consistent with the overall design direction.
Lighting: What It Does During the Day and After Dark
Good lighting design for an indoor pool works across two completely different scenarios, and needs to be planned for both.
During the day, natural light should do most of the work. Artificial lighting should supplement rather than compete with it, and the fittings themselves should be as unobtrusive as possible.
After dark, the character of the space is almost entirely determined by artificial light. Underwater LED lighting is the standard for the pool itself, and the colour temperature and intensity make an enormous difference to how the water looks and feels. Warm white LEDs create an inviting, atmospheric effect. Cool white LEDs feel crisper and more clinical. Colour-changing systems offer flexibility but can easily be overused.
Beyond the pool itself, the lighting around the pool hall matters just as much. Low-level lighting along the pool edge, uplighting on architectural features, and carefully positioned spotlights all contribute to an atmosphere after dark that is genuinely different from the daytime experience.
Bringing the Rest of the Space Together
The pool is the centrepiece, but the wider space around it shapes how the room actually gets used day to day.
Seating and relaxation areas adjacent to the pool invite people to spend time there even when they’re not swimming. A well-placed lounge area, a changing room that feels considered rather than functional, and an outdoor shower that connects the pool to a terrace all extend the usefulness and appeal of the space considerably.
Storage for pool equipment, towels, and accessories needs to be thought about too. An indoor pool hall with no considered storage quickly becomes cluttered, and clutter undermines the calm that most indoor pool owners are looking for.
For the most ambitious projects, features like a spa, sauna, or steam room integrated into the same building create a genuine wellness facility rather than just a pool. The Petham Project incorporated exactly this approach, combining the pool with a jacuzzi, sauna, and indoor kitchen to create a space that works for relaxation and socialising as much as swimming.
Working With an Architect and a Pool Builder Together
The best indoor pool designs come from a process where the pool builder and the architect are working together from the start, not in sequence. The pool informs the building and the building informs the pool. Decisions about glazing positions, structural spans, drainage routes, plant room locations, and mechanical systems all have design implications that are much easier to resolve at the outset than to retrofit later.
XL Pools works alongside architects and design teams on indoor pool projects across Kent and the South East. If you’re at the stage of planning a pool building, whether as a conversion or a new structure, get in touch with our team today. The earlier we’re involved, the more we can contribute to the design, and the better the finished space will be.
You can see what’s achievable by browsing our completed pool projects, or find out more about how we work on our about us page.
