Bathroom Renovation London

A bathroom renovation in London is the smallest room in the house with the highest concentration of trades and the highest cost of failure. If the suite is bought and the room only needs fitting, see our bathroom fitters in London page. This page covers the bathroom where the floor, the waste route or the room itself changes. Most London bathrooms sit on a timber floor, above a room somebody uses, at the far end of a soil stack laid out for a different plan. That is why the parts you cannot see decide whether the room lasts twenty years or leaks in two: the tanking, the falls, the waste runs and the ventilation. It compares wet rooms with walk-in showers, then covers tanking over timber floors, soil stacks and en-suites, the consents, what goes wrong and what it costs in London. GS Renovation has no showroom. We are a builder who does the structure, the services and the fit as one contract.

Across London, a full bathroom refit typically costs £6,000 to £20,000 or more (indicative ranges, MyBuilder and Checkatrade, 2026). GS Renovation Ltd, a building contractor based in Potters Bar, does the work in London: we carry the tanking, plumbing and tiling as one contract, with the electrics certified by a registered electrician.

Wet room or walk-in shower for a London bathroom?

For most London bathrooms on an upstairs timber floor, a walk-in shower on a low tray is the better choice, and a full wet room is right only where the floor and the use justify it. A wet room is the whole floor formed to fall towards a drain, with the tanking carried across all of it and up the walls. On suspended joists that means cutting or building up the floor for the fall and the former, then a membrane that has nowhere to fail. We build them, but each step is a place a lesser job leaks. A walk-in shower keeps the fall inside a factory-made tray, tanks the enclosure only, and reads almost the same once finished.

A wet room earns its cost in three situations. The first is a ground-floor or lower-ground bathroom on a solid slab, where the fall can be screeded and the drain has depth. The second is level access for someone who cannot step over a tray, where the case is practical rather than visual. The third is a large room where the shower is its own zone and the rest of the floor stays dry in use. In a narrow London bathroom with a bath, a WC and a basin in the same footprint, a wet room floor means the whole room is wet after every shower, towels included. Our recommendation is the tray unless one of those three applies.

Tanking and falls over a timber floor in a London terrace

A London bathroom over a timber floor is tanked, because tiles and grout let water through and the membrane behind them is all that protects the ceiling below. The work starts once the room is stripped to the joists. We check them for rot and for notches left by earlier plumbers. Where a joist has to be cut for a drain or a former, the structural engineer we appoint details the trimming. The floor is then decked, the wet areas boarded with a cement or foam backer board rather than plasterboard, and any falls formed so water has one way to go. Tanking follows, liquid or sheet, carried up the walls and sealed around the drain and every pipe.

The tanking has to cure before a tile goes on, and the programme carries that day even when the tiler is standing there. Then the tiling, set out from the sightlines that matter, then the fitting, and only then the silicone, which is the last defence and the most rushed. Building control does not inspect tanking, so the standard is whatever your contractor's standard is. You will be without the bathroom for the whole run. If it is the only one in the house we agree a temporary arrangement before strip-out, and where there are two we sequence them so one always works. Everything in a terrace comes up the stairs by hand, so protection goes down first.

Soil stacks, second bathrooms and en-suites in London houses

Whether a second bathroom or an en-suite is possible in a London house is decided by the soil stack, not by the floor plan. Most terraces have one stack at the back, often the original cast iron run, and every WC has to reach it with a continuous fall inside the floor void or along a wall. An en-suite at the front of the house may be too far. The options are then a new stack, which is a drainage connection under Part H and usually an external pipe on the rear or side wall, or a macerator, a pump that grinds and lifts waste to a small pipe. We fit them where nothing else works, but they are noisy and they fail.

The second limit is water. An en-suite adds a shower to a system sized for one, and a gravity-fed tank or a combination boiler with a modest flow will serve one at a time. A survey checks the pressure and flow before you order anything, because a rainfall head on a poor supply is a dribble. The third limit is the floor: a bath full of water is a real load on joists that were sized for a bedroom. En-suites in London houses are usually carved from the corner of the main bedroom or the box room over the stair, and the layout is set by where the stack is and which way the joists run.

What consents does a bathroom renovation in London need?

A bathroom renovation inside your London home does not need planning permission, and most of it does not need a building control application either, but parts of the building regulations still apply and one of them is notifiable. The exception to the planning rule is a listed house: listed building consent is needed for internal work that affects its character, such as removing a wall or historic fittings, and doing that work without consent is a criminal offence. Electrical work in a bathroom comes under Part P. New circuits, lighting, an extractor, a heated towel rail and underfloor heating are all designed to the zones around the bath and shower, and the work is certified by a registered electrician, with the certificate handed to you. Ventilation is Part F: a mechanical extract fan ducted to outside air, not into the loft void. Drainage is Part H, and a new soil connection or stack is work building control should see. Hot water and scald protection come under Part G.

If the bathroom is in a flat, the lease matters as much as the regulations. Nearly every London lease requires the freeholder's written consent to alterations, and moving a soil pipe or a floor counts. The managing agent will ask for drawings, insurance and a method for protecting the flat below. That is not a formality: the most common bathroom claim in London is a leak into the flat beneath, and a tanked floor with a sealed drain is the protection. The Party Wall etc. Act 1996 rarely applies to a bathroom, unless you cut into a party wall for a recess or a stack. If it does, you serve the notice as the building owner and we build to the award.

What does a bathroom renovation cost in London?

A full bathroom refit in London costs £6,000 to £20,000+, as an indicative London range from MyBuilder and Checkatrade for 2026, and a written quotation after a survey replaces that range with a figure. The bottom of the range is a like-for-like layout with the stack and the supplies where they are, a standard suite, ceramic tiling and a new extractor. The top is a new layout with the soil pipe moved, a wet room floor formed and tanked, porcelain or stone to every wall, underfloor heating, a concealed cistern and a frameless screen. The size of the room matters less than you would expect, because a small en-suite needs the same trades as a family bathroom.

What moves the price is mostly hidden. Moving the WC is the largest single change, because the soil run needs a fall and a floor void to sit in. Rot in the joists, a lead supply, a cracked stack and a subfloor that is not flat all surface on strip-out day, so a quotation should carry a provisional sum for what cannot be seen. Full-height tiling in large format lays slower than half-height ceramic, and natural stone needs sealing and a flatter substrate. A pressure upgrade, if the survey finds the supply cannot serve the shower you want, is a real cost and should be priced before you choose the brassware. The suite itself is one of the smaller lines.

What goes wrong in London bathrooms, and what costs the most to put right

The most expensive things to put right in a London bathroom are the ones under the tiles, and they are also the most common mistakes. A leak through untanked tiling or tired silicone over a timber floor does its damage out of sight: wet joists, a stained ceiling below and, in a flat, a claim from the neighbour beneath. Putting it right means taking the room back to the joists, because a membrane cannot be repaired from the front. A WC or shower waste laid without a continuous fall to the stack blocks and smells, and the fix is lifting the floor that has just been tiled. A joist notched too deep for a pipe sags under a full bath, and the repair needs the trimming detail that should have been drawn at the start.

On a new job, the most expensive single choice is moving the WC, because the soil run needs a fall and a floor void to sit in, or a new stack outside. After that come a wet room floor formed and tanked over timber, full-height large-format or stone tiling, and a pressure upgrade when the survey finds the supply cannot serve the shower you want. The suite is one of the smaller lines. The cheapest way to deal with every mistake above is to design it out. Strip to the joists and check them, board the wet areas, tank and let it cure, duct the fan outside and confirm the stack route first.

Showroom company or builder for a London bathroom?

A showroom bathroom company is the right choice when the layout stays where it is, you want to see the suite before buying, and the fit is the whole job. The design, supply and fitting are one contract and the fitter knows the range. It is the wrong choice when the soil pipe is moving, a wall is coming out, the joists need trimming or the flat below has to be protected. Those are building works the showroom subcontracts or leaves to you. A builder is the right choice for that work, and for a bathroom that is one stage of a wider renovation. GS Renovation has no showroom. We plan the layout on the survey, supply through trade suppliers or fit a suite you have chosen, and carry the structure and drainage.

The bathrooms that fail in London fail in the same handful of ways, and most are choices rather than accidents. Tiles stuck straight onto old plaster with no backer board and no tanking. A fan that vents into the loft. A floor former set over joists nobody checked. Silicone applied on the last afternoon over dust. A macerator chosen because nobody asked where the stack was. Before you sign with anyone, ask what the tanking system is and where it stops, where the extract duct goes, who certifies the electrics, and who is responsible on the day the ceiling below shows a mark. The answers tell you more than the brochure does. If the suite is already chosen and you only need it installed, our bathroom fitters page sets out the fit day by day.

Bathroom jobs in London and nearby, from our MyBuilder reviews

These are bathroom jobs our clients describe in their own reviews on MyBuilder, with the place and the date as published. In Barnet, in October 2021, the job was a "Bathroom Refurbishment" of a small bathroom. The client describes the bath and shower, basin, toilet, pipework and tiles ripped out and replaced, with advice on the design and products. In Enfield, in March 2023, a "Bathroom refurb" meant re-plastering before acrylic panels, re-plumbing the shower waste under a solid floor, building a timber frame for a new shower tray and re-running the pipework inside the wall. In Woodford Green, in March 2018, it was a "New en-suite", with help choosing the products.

In Chigwell, in June 2021, the job line was "Require an ensuite shower room to be completely redone". In Waltham Cross it was a "Medium sized bathroom refurb" in October 2017. In St Albans it was a "Complete new bathroom inc tiling walls & floor" in November 2017. In Lower Edmonton it was "Fit a new bathroom suite" in May 2017, and in Chingford "Bathroom tiles" in June 2021. Some of these jobs are several years old and some sit just outside London, and we say so rather than present them as recent London projects. The reviews carry no prices or photographs, so we show neither. All 31 reviews, the one-star review included, are on our MyBuilder profile.

• Soil pipe and waste re-routing within the floor build-up
• Bespoke vanity units and storage
• Ventilation and extraction ducted to outside

Before committing to bathroom renovation in London, it is worth looking at chimney breast removal in London, bathroom fitting in London and Bathroom Renovation Cost.

The GS Renovation Difference in London

London homeowners choose GS Renovation for a bathroom renovation because the parts that fail are hidden, and one firm carrying the joists, drainage, tanking, electrics and tiling means one person answers for all of them. Founder and director Abdelaaziz Saaid brings over 30 years of hands-on experience to every survey. Where the floor has to be cut, the structural engineer we appoint details it and we build to that detail, with building control coordinated on every notifiable job. We fit a suite you have already bought as readily as one we supply. The trades are our own, the firm is fully insured, and it is rated 4.9 from 31 reviews on MyBuilder.

• The shortest sensible downtime where it is the only bathroom
• Clean, tidy and reliable tradespeople
• Extraction sized and ducted outside, never into the loft

Checked by Abdelaaziz Saaid, founder and director of GS Renovation Ltd (Companies House no. 14611254). Structural design is by the consulting engineer appointed to your project.