What a full bathroom renovation involves
A full bathroom renovation is a coordinated sequence of trades, not a single job handed to one person and left to run itself. We start with strip-out, removing the old suite, tiling and any failed boarding down to the structural floor and walls, checking for damp, timber decay or old lead pipework while everything is exposed. From there we move to first-fix plumbing and electrics: rerouting or extending hot and cold supplies, repositioning the waste run for the WC and shower where the layout is changing, and running new cable for lighting, the extractor fan, underfloor heating controls and any shaver socket. Once first fix is checked and, where notifiable, signed off, we board and tank the wet areas before any tiling starts, then move to second fix, fitting the sanitaryware, taps, shower valve and any underfloor heating controls, finishing with sealant, trims and a final clean. Coordinating these stages properly is what stops a bathroom job overrunning or needing costly rework: a plumber can't move a waste pipe once tiling is down, and an electrician can't chase a wall that's already been tanked and tiled over. We hold that sequence with one point of contact, so first-fix positions for sockets, lighting, the shower valve and any niche or shelf are agreed with you before anything is boarded over, not discovered as a problem once the room is nearly finished and changing it means ripping out finished work. Where tiling forms a significant part of the specification, we work to the same standard and setting-out approach as our dedicated tiling service, since the two trades are effectively inseparable in a bathroom and the finished waterproofing depends on both being done properly together.
What drives the cost of a bathroom renovation
Bathroom cost varies more than most rooms in a house because so much of it depends on what's happening behind the tiles rather than the visible finish alone. Moving the WC or shower to a new position is usually the single biggest cost driver, since a soil pipe needs a consistent fall, typically around 18mm per metre for a 100mm pipe, back to the stack or drain, and where the new position doesn't allow that fall naturally, the floor sometimes needs building up, joists notched and strengthened within Building Regulations limits, or a macerator unit considered instead of gravity drainage. Retiling from scratch costs more once you factor in stripping old tiles, checking and levelling the substrate, and fitting a waterproofing membrane before a single tile goes up, rather than tiling over what's already there. Sanitaryware and fittings vary enormously in price for a similar footprint: a basic close-coupled WC and a wall-hung one with a concealed cistern occupy the same floor space but cost very differently to supply and fit, and taps, shower valves and brassware range from budget chrome mixers to thermostatic bar valves and rainfall heads at several times the price. Underfloor heating, a walk-in shower rather than a bath, and a wetroom floor formed to falls rather than a standard shower tray, all add both cost and time to the programme. We break quotes down by these categories, structural and plumbing changes, waterproofing, tiling, sanitaryware and electrics, rather than a single lump figure, so you can see exactly where a change in specification moves the overall price. As a broad guide, a like-for-like refit with standard sanitaryware and mid-range tiling sits at the more affordable end of the range, a full reconfiguration with a wetroom floor and higher-specification fittings sits considerably higher, and a small ensuite squeezed into an awkward space can sometimes cost more per square metre than a larger, more straightforward bathroom, simply because the fixed costs of plumbing, tanking and electrics don't shrink in proportion to the room size.
Tanking, waterproofing and wet zones
Any area that gets wet regularly needs proper waterproofing behind the tile, not just grout and silicone holding the water back at the surface. We follow the zone approach set out in BS 5385 for tanking: the shower enclosure itself, the floor area immediately around a bath, and a reasonable margin beyond a basin splash zone all get a waterproof membrane, either a liquid tanking system rolled onto boards in several coats or a bonded sheet membrane taped at joints and corners, before any tile adhesive goes on. Shower trays and formed wetroom floors are treated differently. A shower tray sits on a supporting frame or upstand, with the membrane dressed up the surrounding walls and over the tray edge so water can't track behind it, while a true wetroom floor is built to fall towards a linear or point drain, using a tapered former or a screed laid to falls, with the membrane taken up the walls and across the whole floor area, not just around the drain itself. Getting the falls wrong on a wetroom floor is one of the more expensive mistakes to correct after tiling, since standing water pooling away from the drain usually means lifting the floor and starting the build-up again from scratch. We pressure-test or flood-test waterproofing on wetroom floors and shower enclosures before tiling wherever practical, leaving standing water in place for a set period and checking below for any sign of a leak, rather than assuming a membrane has taken without checking it. Finding a pinhole or a poorly sealed corner joint after the tiles are down is a far bigger and more disruptive job than finding it before a single tile has been laid.
Electrics, ventilation and lighting in bathrooms
Bathrooms are a special location under BS 7671, the UK wiring regulations, and the room is divided into zones based on distance from water: zone 0 is inside the bath or shower itself, zone 1 covers the area directly above it up to 2.25 metres, zone 2 extends a further 0.6 metres beyond that, and everywhere outside those areas is treated as zone 3 or unzoned. Fittings need an ingress protection rating suited to the zone they sit in: a shower light typically needs at least IP65 if it's positioned in zone 0 or 1, and standard 13-amp socket outlets aren't permitted within the zoned area at all, other than a shaver socket to BS EN 61558-2-5, which is the reason bathrooms only ever have a dedicated shaver point rather than a normal switched socket near the basin. Mechanical extraction is a Building Regulations Part F requirement, not just good practice, and a bathroom without an openable window to outside air needs a fan ducted out, sized appropriately to the room volume, and in windowless bathrooms it typically needs a timer overrun so it keeps running for several minutes after the light switches off rather than stopping the moment you leave the room. Switch position is worth planning early in a small bathroom too. A standard light switch mounted on the wall inside the room needs to sit outside the zoned area or be a pull-cord type if it's within reach of the bath or shower, which is why older bathrooms often have a ceiling-mounted pull-cord even where a modern wall switch would otherwise be preferred. In a tight ensuite where every wall is close to the bath or shower, this sometimes limits switch position more than people expect, and it's worth confirming with the electrician at first-fix stage rather than after the wall's already been tiled. We coordinate all of this electrical work with a qualified electrician who tests and certifies it, since bathroom electrical work is notifiable under Part P of the Building Regulations, and we build the certification into the handover pack alongside the rest of the job's documentation and photographs.
Small bathrooms, ensuites and London flat layouts
A lot of London's housing stock was never built with a second bathroom in mind, so ensuite and small bathroom projects usually involve working around genuine space constraints rather than starting from a blank canvas. In Victorian terraces, a boxroom or the end of a landing is often the only realistic space for an ensuite, and getting a shower, WC and basin into 2 to 3 square metres means specifying carefully: a corner shower or a shower over a shortened bath, a wall-hung WC with a concealed cistern to save floor depth, and a slimline or countertop basin rather than a full vanity unit, all chosen to suit the actual room rather than a standard catalogue layout. Ex-council and purpose-built flats bring a different constraint: concrete floor and ceiling construction limits where new pipework and waste runs can be chased in, since cutting deep chases into a structural concrete floor slab isn't something we'd do, so waste routes sometimes need to run in a raised floor void, a boxed duct along a wall, or a false ceiling in the room below instead. Door swing is another common problem in small bathrooms that's easy to overlook on a plan, an inward-opening door can eat into the only usable floor space in the room once a shower enclosure or WC is in position, and switching to an outward-opening or sliding pocket door is often a simple change that makes a genuinely tight layout workable without extending the room itself. Ceiling height under a sloped loft conversion roof, and the position of a soil stack shared with a flat above or below, are further constraints worth checking early in a converted property. We measure and mock up tight layouts with masking tape on the floor before ordering sanitaryware, since a fitting that looks fine on a plan can turn out to clash with a door swing or a radiator once it's actually standing in the room.
How bathroom renovation fits with other trades
A bathroom renovation rarely stays entirely within the bathroom walls. Moving a waste pipe sometimes means lifting floorboards in the room below or accessing a void through a neighbouring room, and rerouting a soil stack in a converted flat can affect a shared wall or a floor void serving the flat below, which needs planning around and, in some cases, notice to a neighbour rather than discovering the constraint once floorboards are already up. Where the property is part of a wider refurbishment, we sequence the bathroom alongside the rest of the programme so first-fix plumbing and electrics happen at the same stage as the rest of the house, rather than as an isolated job that holds up decoration and second-fix work elsewhere in the property. Tiling within a bathroom renovation is delivered to the same standard as our dedicated tiling service, since the two are effectively one job in practice and the finished waterproofing depends on the tiling and the tanking beneath it being coordinated properly, but where a client only wants the existing bathroom retiled without a full refit, that smaller scope sits under our tiling service instead rather than being priced as a full renovation. We also coordinate with plasterboard repair where a wall needs opening up for new pipework or cabling and making good afterwards to match the surrounding finish, and with leak repair where a bathroom renovation follows water damage that needs the affected structure properly dried out and reinstated before the new suite goes in, rather than building a new bathroom on top of a problem that hasn't actually been resolved. Having one team responsible for the whole sequence avoids the common problem of a tiler being booked before the plumber has confirmed final fitting positions.