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Stone-lined lower-ground swimming pool under a slatted timber ceiling, with lit coves and loungers along one side

Indoor Swimming Pool Construction and Home Spas

The pool, the spa and the house around them, built by one team.

Craftex team

500+ major construction projects delivered
(combined team experience)

Pool, spa and prime home projects we have delivered

  • 16 weeksto refurbish the Francis Holland School pool, ready for the new term
  • 17 weeksto design and build the four-floor Medusa spa in Knightsbridge
  • 60%of the work on our sites, done by our own people
  • £10Mpublic and employers' liability cover on every project

A pool built as part of the house, not added to it

Craftex handles indoor swimming pool construction for prime homes in London and the Home Counties: basement and lower-ground pools, garden-wing pool halls, and the sauna, steam room and changing suite around them. We design and build the whole room under one contract, from the dig and the structural tank to the plant, the air and the last tile, so one team answers for the pool and the house above it. Indoor pool installation is never a separate trade on our sites.

Most pool builders arrive with the tank and the plant and leave the rest to someone else. We build the room, the structure and the house around the water. Our architects and an RICS-qualified quantity surveyor are on the team from the first drawing.

Indoor pool hall in dark slate with oak loungers and full-height glazing onto the garden
Pool edge in honed slate with a flush coping, backlit stone wall and oak loungers beside the water

The pool specialists and spa suppliers we bring in work under our contract. They answer to our site manager, so you deal with one team. Around 60% of the work on our sites is done by our own people. The tank, the plant room, the air handling, the stone and the joinery are planned together. Nothing is left for the last trade on site to solve.

Trusted by leading businesses

  • Trainline
  • Auto Trader
  • YouTube
  • Medusa
  • Fuse
  • Drakes
  • PTOS
  • Close Connections
  • Marnie
  • Vortex Post
  • Minds Ahead
  • Missy
  • Fora
  • Gama Healthcare
  • Equinix
  • Hubble
  • B-Engineering

What we build: pools, spas and wellness rooms

Six parts of one wellness floor, designed and built by the same team.

Lower-ground pool lined in timber, with stone entry steps and warm lighting set into the ceiling and the water

Basement and lower-ground pools

A pool under the house, dug, held up and kept dry, often as part of a basement conversion.

Glazed pool pavilion with a timber and glass roof, a mosaic-lined pool and planting along the glass

Garden-wing pool halls and glazed pavilions

A new wing or pavilion, with the glazing, roof and air designed around the water.

Drained concrete pool tank with the lane markings exposed, the structure seen before new finishes

The structural tank, waterproofing and finishes

A watertight shell, tested full before a single tile goes on.

White plant-room pipework with three isolation valves

Plant room: filtration, heating, dehumidification

Filters, pumps, heating and air handling sized to the pool, with room to service them.

Modern timber sauna behind a glass front, with lit benches and a stone heater

Saunas and steam rooms

Timber saunas and tiled steam rooms built into the house, with their own power, drainage and ventilation.

Marble steam room with a black mosaic bench, downlights and a stone basin

Plunge pools, hammam, changing rooms and the home gym next door

The rest of the spa suite, finished to the standard of the pool.

Where does an indoor pool go in a London house?

Lower-ground pool with sofas at one end, opening onto a sunken courtyard behind a timber screen

There are three places. A new basement gives the most room but asks the most of the structure and the planning. A lower-ground floor is quicker if the depth is there already. A garden wing brings daylight and views, with planning to match. Before you choose, we check the structure, the borough's policy and the access. The pool then goes where the house allows it.

Read more

Concrete or stainless-steel tank. A reinforced concrete tank can take any shape and is cast with the structure. A stainless-steel tank is made off site and lifted in, which suits some basements and roof-level pools. The choice depends on access, shape and finish.

Skimmer or deck-level overflow. A skimmer pool keeps the water a little below the edge. A deck-level pool brings the water up to the floor and spills it into a hidden channel. That needs a balance tank and more plant space.

Borough basement policies. Inner London boroughs set their own basement rules. Examples are RBKC Local Plan Policy CD11 and its Basements SPD, Westminster City Plan Policy 45 and Camden Local Plan Policy A5. We read the policy for your street before the design is fixed.

Swim spa or full pool. A swim spa is a shorter tank with a current to swim against. It needs less depth and less plant, but it is not the same as a full-length pool.

How an indoor pool is built, from survey to first swim

01

Survey, structure and planning check

We survey the house, the ground and the access, and read the borough's policy.

02

Design with the pool engineer

Our architects and the pool engineer design the tank, plant and air together.

03

Excavation, structure and tank

We dig, build the structure and cast the tank, then water-test it before any finishes.

04

Plant room, M&E and dehumidification

Filtration, heating, electrics and air handling go in and are tested.

05

Tiling, stone, lighting and joinery

The finishes go on a tested, dry structure.

06

Commissioning and handover

We commission the water and the plant, then train you on both.

Saunas, steam rooms and the spa around the pool

Timber sauna with benches on both sides and a round stone heater set into the floor

Sauna installation

A traditional sauna or an infrared cabin, lined in timber chosen for heat. The heater, controls and ventilation are planned into the room. We build it into a basement, a bathroom or the pool hall, with the power and the air it needs.

Travertine-lined steam shower with a stone bench, rain head and black digital controls

Steam room installation

A steam room is a wet room under constant heat. It needs full tanking, a steam generator with service access, falls to the drain and a sloped ceiling. That way condensate runs off rather than drips. Plunge pools and showers sit next to it, finished in the same stone or mosaic.

Refurbishing an existing pool or spa

Refurbished school swimming pool with new tiling, rooflights and new lighting along the ceiling beams at Francis Holland School

Swimming pool refurbishment brings an old pool up to date without rebuilding the house. New tiles, plant, air handling, lighting and finishes go in while the house is lived in. At Francis Holland School we refurbished the pool and its facilities, 1,250 m², in 16 weeks. The school stayed open and the pool was ready for the new term. See the Francis Holland School pool refurbishment.

Read more

A refurbishment starts with a survey of the tank, the pipework, the plant and the air handling. We find what can stay and what has to go before we price. The house is then opened up only where it must be.

The Craftex Guide to Residential Design and Build, shown as a printed book

The Craftex Guide to Residential Design and Build

Six promises, written into your contract

  1. One team for the pool and the house

    Structure, tank, plant, air and finishes under one contract.

    Medusa, a four-floor spa designed and built by one team.

  2. The tank is water-tested before finishes

    No tile goes on a tank that has not been filled and checked.

  3. Plant you can reach

    Every pump, filter and air handler has a service route, agreed on the drawings.

  4. A fixed programme

    The date is set from the design before you sign.

    Francis Holland pool, ready for the new term.

  5. £10M cover on every job

    Public and employers' liability of £10 million each.

  6. Zero snags, every certificate

    Handover with the test records, the electrical certificates and the plant manuals.

    Herbert Crescent, 450 m² prime home refurbished beside its neighbours.

A pool and spa quotation from another contractor with a sticky note: Send it to us. We'll beat it.

Already have a quote? Send it to us. We'll beat it.

Holding a quote from a pool builder or a main contractor for your pool, spa or basement? Send it to us. A director reviews it and replies the same working day. You see line by line how we beat it for the same scope.

Where indoor pools go wrong, and what we do instead

AreaUsualWith Craftex
CondensationDehumidification undersized, so the walls and ceiling run wet.Air handling sized to the water area, with a vapour control layer in the build-up.
Leaks found lateThe tank is tiled before it is tested.The tank is filled and checked before any finishes.
No way to the plantThe plant room has no access route for service or replacement.The route is on the drawings from day one.
Slippery surroundsPolished stone chosen for looks.Surrounds with a slip rating fit for wet bare feet.
Electrics in the wrong zonesLighting and sockets not set out to the pool zones.Electrics designed to the pool zones in BS 7671.
Three contracts, no ownerPool specialist, builder and M&E each blame the other.One contract and one team answer for all of it.

What sets the cost of an indoor pool?

We do not publish pool prices: each one depends on the house and what you want in it. These six things decide the cost, and here is what we do about each.

What moves the costWhat we do
Size and depth of the poolWe size it to how you will use it, not to the biggest hole
A new basement dig or an existing roomWe survey the ground and the structure before we price
Tank type: concrete or stainless steelWe choose by access, shape and finish
Plant and dehumidificationWe size the air and the plant to the water area
Finishes: stone, mosaic, joineryWe price each finish from samples you approve
The spa suite: sauna, steam, plungeWe plan the suite with the pool, in one design

Our team

  • in

Indoor pool and spa questions

Can you build a swimming pool in a basement?

Yes. A basement pool needs a structural tank, full waterproofing and room for the plant, all built with the house held up above it. We do it as part of a basement conversion.

Do we need planning permission for an indoor pool?

It depends on the house. A new basement or garden wing often needs consent, and each London borough has its own basement policy. A listed house needs listed building consent too. We check yours before design starts.

How do you stop condensation in a pool room?

With dehumidification sized to the water area and the air temperature. A vapour control layer goes in the walls and roof. Both are designed before the structure is built, not added at the end.

Concrete or stainless-steel pool tank?

Concrete takes any shape and is cast as part of the structure. Stainless steel arrives made off site and is lifted in. That helps where access or programme is tight. We advise on yours after the survey.

How long does an indoor pool take?

That depends on the dig, the structure and the finishes. The programme is fixed from the design before you sign, and it is written into the contract.

Can you add a sauna or steam room to an existing house?

Yes. A sauna needs power and ventilation; a steam room needs tanking, a drain and a steam generator. Both fit into a bathroom, a basement or a spare room.

Do you build pools and spas for hotels, clubs and schools?

Yes. We refurbished the Francis Holland School pool on a live school site. For clubs see our gym and spa fit out for clubs, and for hotels our hotel refurbishment service.

Who looks after the pool after handover?

You do, with our help. We train you on the water and the plant at handover.

Do you work outside London?

Yes. We work across London first, and also in Surrey and the Home Counties.

How fast do you reply?

The same working day. Send us your drawings, your quote or a few lines about the house, and we come back to you that day.

What our clients say

See all reviews on Google
  • I and my husband are very satisfied with Craftex's service and customer support. We bought a house in Hampstead and wanted to redesign and renovate it. On our initial free consultation with Sviat, we found out that we actually can do loft conversion and rear extension and add value to the property straight away.
    We worked with the Craftex design team to bring our vision to life and deliver planning approvals. At that time guys started stripping out to save time on the construction programme as we wanted to move in ASAP.
    We worked with very experienced project director Konstantin who was responsible for all aspects of project delivery from design to construction with a very good eye on details and customer care.
    We saved a lot of money by having professional advice from the start. Project management and quality at Craftex are at the highest level. Many thanks to Craftex Team.

    Lia Lavryk

  • This was a full high-end renovation of my Victorian rental apartment in Westminster, just off Sloane Square and Belgravia. The scope included full fit-out: electrics, plumbing, a new bespoke kitchen, and a luxury bathroom refurbishment. Craftex took care of everything and made the process easy. They weren’t the cheapest, but you can tell they really know what they’re doing when it comes to prime London property renovations.
    The team was professional, organised, and genuinely seemed to care about getting everything right. I was especially impressed with the quality of the finish – the attention to detail really shows in every corner.
    I’m very happy with the results and would definitely recommend Craftex to anyone looking for reliable, high-quality renovation work in Central London.

    Наталия Цимбалюк

  • Very professional company. Craftex did brilliant minimalistic design and completely refurbished my apartment to the highest quality.

    Vlad

  • Great experience from start to finish. Communication was clear, the workmanship was excellent, and the whole project was managed professionally.

    Rhea Langford

  • Hired Craftex for our conversion project. We had to convert a 600m2 office into 8 apartments. Guys did an excellent job in terms of program efficiency and quality of the finishes which gave us a big upside to exit the project 2 months faster than other competitors’ timelines.

    Misha Levit

  • I’d like to thank the team at Сraftex for the work they did on our office.
    It was really important for us to get the work done quickly, but without compromising on quality, as we regularly have clients and guests visiting and needed to move into the new office within a month.
    We spent around two weeks discussing and agreeing all the details before the work started. What I really appreciated was that everything we agreed beforehand was actually followed through during the job. The work was also completed on time.
    Thanks to the whole Сraftex team for a great job. I’d definitely use them again if we need any work done in the future.

    IURII PYLYPETS

  • We recently worked with Craftex and honestly couldn’t be happier with the results. From start to finish, the team was professional, reliable, and highly skilled. The quality of workmanship exceeded our expectations, and everything was completed on time and to a very high standard.
    Communication throughout the project was excellent, and they always went above and beyond to make sure we were satisfied. It’s rare to find a construction company that combines professionalism, attention to detail, and great customer service so well.
    Without a doubt, Craftex is one of the best construction companies we have ever worked with. Highly recommended to anyone looking for quality and trustworthy builders.

    Adam Miah

  • Craftex has completed a range of both small and large-scale projects on our commercial property with exceptional precision and quality. Dmitriy consistently delivers courteous, prompt service and has shown great flexibility in accommodating last-minute changes to plans and timelines. I highly recommend Craftex for their professionalism and outstanding workmanship.

    Pascal Hunt

  • Great company to work with as always. Super flexible at dealing with evolving requirements and fast deployment and execution.

    Akshay Khanna

  • Hired Craftex to do the full design and fit out of my gym in Chelsea. Super efficient and fast team. They gave the best price and a proper fast track program. We managed to open in less than 6 weeks with no headaches or surprises during construction. Quality was great, we had zero snags on completion. I’ve worked with a few companies before but these guys really impressed me from project management to how they treat the client. Top GGs.

    Александр Хоменко

  • I worked perfectly with Sviat and Joe, with their architect they came up with a very smart design for our office to fit more desks and optimise the space to its maximum capacity. They also did excellent value engineering on the MEP design proposed by others, allowing us to save around £50K. The quality and speed were outstanding we finished two weeks ahead of schedule. Highly recommend these guys.

    John Smith

  • Happy with the end result. Tight timeline but they pulled it off. The team worked late shifts and even weekends to help us open the doors on schedule. Site was always left tidy at the end of the day and no surprise charges either. Good communication throughout. Would definitely use Craftex again.

    Pawel Kamionka

  • Highly recommended!
    Craftex are the kind of fit-out contractors in London you can truly trust. From the very first meeting, they understood our vision and gave practical ideas to make the most of our space. They turned our old storage area into a clean, efficient, and well-organized warehouse. The team was professional, easy to work with, and clearly took pride in their work.

    Monika Kamionka

  • We brought in Craftex to refurb our London office and honestly, they made the whole thing way easier than we expected. They listened, suggested ideas we wouldn’t have thought of, and explained everything clearly. Not the cheapest quote we got, but the end result shows why, the place looks modern, clean, and our team actually enjoys being here now. Communication was spot-on too. No chasing and confusion, deadlines were hit. If you want people who genuinely care and don’t treat your project like “another job,” I’d recommend them.

    A Google User

  • Sviat and his team at Craftex were brilliant to work with on our office redesign. From the first meeting, they took the time to understand how we actually use the space rather than just pitching generic solutions. They came back with clever, practical ideas to maximise use of the space and get more employees and desks inside . Every step was handled professionally, and the process felt surprisingly smooth for a project of this size. They finished one week ahead of schedule, and the transformation is clear — our office feels brighter, more functional, and much more welcoming. I’d happily recommend Craftex to anyone who wants a reliable design team that also makes the journey enjoyable.

    Cucu Iulian

  • We recently worked with Sviat and the Craftex team on a complete warehouse refurbishment, and the results have been outstanding. From the very beginning, their team was professional, organized, and attentive to every detail. The project was completed on time and within budget, without disrupting our day-to-day operations.

    Simone Racaku

  • My experience with Craftex was excellent from beginning to end. They took the time to really listen to what I wanted and then offered practical suggestions that made the design even better. I always felt like they cared about creating a space that worked for me, not just one that looked nice on paper. The end result is an office that feels stylish, welcoming, and very functional for day-to-day work. The process itself was straightforward, well-managed, and never stressful. I’d definitely recommend Craftex if you’re looking for office design and build services in London — they made the whole journey a positive one.

    Ion Bounegru

  • I’m really pleased with my experience working with Craftex. As a commercial construction firm, they handled everything from start to finish without any unnecessary stress on my side. What impressed me was how they suggested practical ideas that improved the design while also keeping things realistic. The communication was always clear, so I never felt out of the loop. The project ran smoothly, deadlines were met, and the end result is exactly what I was hoping for — a space that feels both functional and modern. It’s not easy finding contractors who are this reliable, but Craftex definitely proved they can be trusted.

    Taron Papoyan

  • I had an amazing experience working with Sviat and the Craftex team on our office fit-out in London. They were always professional, responsive, and quick to offer the best advice whenever decisions needed to be made. I really appreciated how they balanced style with practicality — the office doesn’t just look fantastic, it works perfectly for our team. Everything was done with care and attention to detail, and the project never felt overwhelming because they managed it so well. Communication was clear from start to finish, and I always felt involved in the process. I would happily recommend Craftex to anyone looking for a trustworthy contractor.

    Artur Dvorak

  • Craftex carried out a warehouse fit-out for us, and I couldn’t be happier with the outcome. The space has been completely transformed into a highly organized and efficient environment that makes our daily operations much smoother.
    The team was professional but also very approachable — I always felt comfortable asking questions or giving feedback. They came up with smart, practical solutions that worked perfectly for our setup, and everything was explained clearly along the way.
    The best part was how they stuck to the agreed timeline, finishing on schedule without cutting corners. It’s rare to get both quality and reliability, but Craftex delivered both.

    Roma Shchukin

  • We’re extremely happy with Sviat and the Craftex team’s work. They suggested clever ideas, managed the project efficiently, and delivered a functional, modern space. The team was easy to communicate with and very professional throughout the process!

    Polina Lysenko

  • I can honestly say our office has been completely transformed thanks to Craftex. From the very first meeting, the team was approachable, professional, and full of creative ideas that really made sense for our business. They didn’t just focus on how the space would look but also how it would work for the team day-to-day. The new layout is efficient, modern, and welcoming, and you can tell they really thought about the details. The whole process was smooth and surprisingly stress-free. They kept me updated at every stage, which gave me confidence. I’m really happy with the results and wouldn’t hesitate to recommend them to anyone.

    Mykyta Khadzhynov

  • The results from Craftex’s commercial refurbishment in London are fantastic. The team was friendly, clear in communication, and made sure the project stayed on track. The workspace now feels efficient, welcoming, and modern. Definitely a team you can trust!

    Alaa Betar

  • We hired Craftex for a commercial ground floor fit-out with 2 flats above. There were some minor co-ordination hiccups with third-party suppliers but the team kept it moving. Finish quality was strong. Kitchens and doors look great. I have already asked them for a quote on the next project.

    Ben Edell

  • These guys actually deliver. They handled our first industrial to residential conversion near Tower Bridge, turned an old warehouse into 4 modern flats. They stuck to the plan, kept the site clean and the timing was on point. No hidden extras, no drama, just a professional construction company in London that gets the job done.

    Богдан Главацкий

  • We recently hired Craftex for a commercial office fit-out project in Central London, and overall, we’re really happy with the result. There was a delay on our side with a custom glass partition supplier, but the Craftex team managed the construction schedule very professionally and kept everything on track. Their guys worked clean, respected our workspace and IT setup, and kept the site tidy throughout. If you're looking for a reliable office refurbishment company in London, I’d definitely recommend Craftex. Would use them again without hesitation.

    Ardian Beleshi

  • I was stressed about timing since we had bookings lined up, but they smashed it. Even worked Saturday to finish the floor. My clients love the look — the beauty salon fit-out turned out exactly how I wanted. Couldn’t have pulled it off without their help. Genuinely appreciate the way they communicated throughout the refurbishment. If you need reliable help with beauty salon design or fit-out, especially in a place like Chelsea — these are the guys.

    Rami Jusupova

  • We used Craftex for a shop-to-flat conversion in Chelsea — turning an old retail space into two rental units. Access wasn’t the easiest, but the guys handled it well, no drama. Quote was clear, no hidden extras, and they actually stuck to it, which is rare. Finish came out solid, exactly what we needed for rentals. Joe (PM) kept things ticking and communication was always on point. All in all, smooth job — would use them again for sure.👍

    Apartify Estates

  • Fuse Energy hired Craftex on the fit-out and installation of our engineering and research centre, which included electrical, heating, lighting, plumbing, and ventilation upgrades. They delivered everything to a high standard and were proactive throughout — even working weekends to help speed up the programme, despite not being contracted to. They managed last-minute changes very well, communication was clear and consistent, and the team was professional from start to finish. We’d happily recommend Craftex to anyone needing a reliable construction partner.

    Hainro Eybers

  • Holistic therapy space fit-out
    Super impressed. I had a very specific vision for the studio. calm tones, soft lighting, hidden storage etc. the craftex team just got it. build was done quicker than I expected and the guys were polite, tidy and actually listened. we had 2 snags on day one but they fixed it before the week was out. worth it for the peace of mind.

    Dariia Shvyryda

  • Made a full refurbishment and redesign of our Central London office. Fantastic work, quality service and reliable people. Can recommend it to everybody

    Nikita Nigai

  • Amazing experience with these guys. I trusted them my apartment in London and Business. They are always accurate, very professional, responsive and neat. They would always advice me right things for my best interest. I had luxury experience with them and I would definitely recommend Craftex to everyone.

    Motush Motushev

  • Could not be HAPPIER with Sviat and the Craftex team, they certainly showed me that they’re the number one office design company in London that we’ve had the pleasure of working with. They gave us a unique design just like we wanted, and we loved the first initial draft of the concept. Also have to give them props for Construction, I gave them a tight timeline as we needed to move our team in ASAP, so they pulled double shifts and I didn’t see a drop in quality. Will be to talking to the team when we move up to our next bigger office. Highly recommended A+++

    Mikhail Burdoev

  • ISO 9001
  • ISO 14001
  • ISO 45001
  • CHAS
  • Constructionline Gold
  • SafeContractor
  • TrustMark
  • FMB
  • NICEIC
  • NAPIT
  • MCS
  • CSCS
  • Considerate Constructors
  • RICS, Royal Institution of Chartered Surveyors
  • RIBA, Royal Institute of British Architects
  • ARB, Architects Registration Board
  • Public & Employers' Liability £10M
  • Professional Indemnity £10M
  • ISO 9001, 14001 and 45001 certified

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