Toilet renovation: cost of a toilet renovation 2026

A separate WC is one of the smallest rooms in a home, yet it often holds more services than the living room. There is a large waste pipe, a water supply, often the soil stack that serves the whole building, and some form of ventilation. When you renovate a WC, the layout matters less than the many small details that are easy to forget.

In prefabricated concrete panel blocks, which you find in many European cities, the WC is usually narrow, often just over 80 cm wide. The shared soil and water stack runs behind the toilet or in a corner. In many of these flats the original bathroom core also contains the WC. If you strip out the whole core at once, it is a good moment to decide whether the WC stays separate or joins the bathroom. A separate WC helps in a larger household, when everyone gets ready at the same time in the morning. Merging the two rooms gives you space for a washing machine or a bigger shower.

In older brick-built flats, taking out the toilet often reveals a cast-iron waste pipe with lead or putty joints and steel water pipes narrowed by limescale. In a house you usually have more freedom. You can often move the toilet a little or add a small hand basin without major building work.

Replacing a toilet, a basin or tiles does not normally need a permit. Work on load-bearing walls, moving the stack or changing the layout of rooms is a different matter, and local building regulations may require a notification or an application. Do not guess: check the scope of your work with the local building authority before you start. In a block of flats, also speak to the building management or the owners' association in advance, especially if someone has to shut off the water in the stack.

A close-coupled WC has the cistern sitting directly on the pan. It is easy to fit and easy to repair, because everything is in sight. When the fill valve wears out, you replace it without touching the tiles. The downside is cleaning: the base of the pan and the area behind the cistern are awkward to reach with a cloth.

A wall-hung WC hangs on a concealed frame. The floor underneath stays clear, the cistern disappears into a false wall and the room looks larger. The false wall does take up depth, roughly 15 to 25 cm depending on the frame and the cladding. In a narrow panel block WC you will notice this. Before you decide, measure from the back wall to the door and picture whether the door will still open comfortably once the toilet is in, and whether you can still sit down without bumping your knees.

There is a third option: a floor-standing WC connected to a concealed cistern. It suits rooms where the wall or floor cannot carry a load-bearing frame, or where you want to hide the cistern but prefer to avoid the more involved installation.

The frame carries the whole toilet and the person sitting on it, so it is fixed to both the floor and the wall. The manufacturer states the load capacity, and for common frames it is usually several hundred kilograms. That figure only applies if the frame is fixed exactly as the instructions say. A lightweight partition or an old, crumbly floor needs suitable anchors. If someone skimps on them, the toilet starts to move over time and the silicone joint at the tiles cracks.

Seat height

You set the height of a wall-hung pan on the frame before it is clad. The usual figure is around 40 to 42 cm above the finished floor. For taller or older people a higher position is common, roughly 45 to 48 cm. The key word is finished: count the tiles and the adhesive, not the bare concrete you are standing on. In practice it often happens that the frame is set from the rough floor, and once the tiles go down the toilet ends up lower than planned.

False wall: boards or blockwork

The frame is clad with moisture-resistant plasterboard or cement boards, or built in with aerated concrete blocks. A blockwork false wall is stiffer and muffles the sound of flushing better, which the neighbours on the other side of the wall will appreciate. Boards are quicker. Whichever you choose, it pays to form a shelf above the frame. It hides the pipework and gives you somewhere to put spare toilet rolls or an air freshener.

A toilet needs a large waste pipe, usually DN 100, with a steady fall towards the stack. Every extra bend and every extra metre raises the risk of a blockage. That is why the toilet in a flat usually stays close to where it was. Moving it by half a metre is often possible. Moving it to the opposite wall in a panel block usually is not, because you must not cut channels into the concrete floor slab.

A new toilet connects to an old cast-iron stack through a suitable adaptor with a seal. If the cast-iron socket is cracked or the joint leaks, a section of the stack has to be replaced. The stack belongs to the whole building, though. Agree any work on it with the building management, and ideally with the neighbours above and below, so that it can all be done in one go.

While you are replacing the toilet, change the angle valve on the water supply as well. After years of use an old valve often no longer closes fully. Replacing it after the tiling is finished is an unnecessary hassle.

Most WCs in flats have no window. They were originally ventilated naturally through a grille into a shaft, and that rarely does much. Building regulations in many countries expect some form of extract ventilation in a windowless WC, so an extractor fan is usually added during a renovation. A guide figure of around 25 m³ per hour is often quoted for a WC. How much air the fan really moves, however, depends on the length and diameter of the duct.

Choose a fan with a backdraught shutter, otherwise smells from the shaft will drift back into your flat. Just as important is where the fresh air comes from. If the door closes tightly right down to the floor, the fan has nothing to pull in. A gap under the door or a door with a ventilation grille solves this.

In blocks of flats with a shared duct and a fan on the roof, you often cannot connect your own motorised fan without the building management's consent. It could upset the ventilation in the other flats. The usual answer is a passive or natural draught outlet that follows the building's rules. A fan can run from the light switch with an overrun timer or from a humidity sensor. Only a qualified electrician should connect it to the mains.

A WC without a basin is impractical from a hygiene point of view. Anyone who wants to wash their hands has to touch door handles on the way to the bathroom. That is why a small hand basin is often added during a renovation. In a narrow room, corner models or basins around 20 to 25 cm deep work well, because they do not get in the way in front of the toilet.

If cold water is enough for you, you need one outlet and a simple valve. Hot water means either another supply pipe from the bathroom or a small water heater under the basin, which needs its own socket. The basin waste can run inside the false wall together with the toilet waste. If you are installing the frame now, that is a big advantage.

On one or two square metres, every joint shows. Set out the tiling from the centre line of the toilet, so that the pan and the flush plate sit in the middle of a tile or exactly on a joint, not just anywhere. Position the flush plate so that the access opening does not leave a thin sliver of tile.

Large tiles look calm in a small room, but on uneven walls they need a properly levelled surface. Smaller tiles forgive more unevenness and make it easier to work around the stack in a panel block. Slip-resistant floor tiles are worth having in a WC, especially if you have a bidet spray.

You do not need waterproofing on the same scale as in a shower. At a bidet spray, at the hand basin and on the floor under the toilet, a waterproof coating is still worthwhile. If something leaks at the toilet, you often only find out when the neighbour downstairs calls about a stain on their ceiling.

A renovation is a good time to think through the lighting, the fan and perhaps a socket for a shower toilet or a water heater. Shower toilets with warm water and a dryer need a socket behind the false wall. Plan it when the frame goes in, because afterwards it is too late. Any work on the electrics belongs to a qualified electrician, who should give you a certificate for the work once it is finished.

The toilet roll holder, toilet brush and towel hook are fixed through the tiles. With a board-clad false wall, decide their positions in advance, so that solid backing can be built into the frame at those points. Otherwise the accessories will gradually work loose in the plasterboard.

The WC is small, but the work does not all happen at once. Between setting the frame, cladding it, tiling and fitting the toilet, you have to wait for the adhesive and grout to cure. If your home has only one toilet, agree a stopgap in advance. That might mean temporarily refitting the old pan overnight, or a precise order of work so that you are not without a WC for longer than necessary.

A WC renovation brings together plumbing, building work, tiling and electrics. That is why it helps to have one tradesperson or one company responsible for the whole job. When the work is split between several trades, it easily happens that nobody tests the frame for leaks before it is clad.

You can replace a toilet seat yourself without risk, because you do not touch the water or the electrics. You just need to get the right shape and the right type of fixing.

1. Measure the length and width of the pan and the distance between the fixing holes, or identify the pan model from the mark on the ceramic.
2. Unscrew the old seat; on wall-hung toilets this is usually done from above after lifting the hinge covers.
3. Clean dirt and limescale from the holes and around the hinges.
4. Insert the new fixing pins or bolts with washers as the manufacturer's instructions describe.
5. Fit the seat and centre it so that it does not overhang the rim of the pan.
6. Tighten the fixings gently so that the ceramic does not crack.
7. Check the soft-close action and that the seat sits firmly, then tighten the fixings once more after a few days of use.

• The toilet sits firmly and does not move or creak when you put weight on it
• The seat height matches the agreed height above the finished floor
• The flush works with both the full and the reduced button, and the cistern does not keep running after it fills
• The access opening behind the flush plate is reachable and opens without damaging the tiles
• The joint between pan and waste pipe and the water connection stay dry after several flushes
• Wall and floor tiles are flat, the joints are even and the cuts around the stack are clean
• The silicone along the floor and around the pan is continuous and free of bubbles
• The fan has a backdraught shutter, draws air when switched on, and there is a gap under the door for fresh air
• Nothing drips under the basin trap and the tap closes fully
• You have received a certificate for the electrical work