What Is a Concealed Shower?
A concealed shower hides all functional components, including pipework, valve mechanism, and shower head connections, behind the wall surface. Only the controls and shower head protrude from the finished wall, creating a clean, minimalist appearance that many homeowners prefer in modern bathroom designs. The valves and pipes are mounted within the wall cavity or behind a false wall, and the surface is finished with tiles, shower panels, or plasterboard for a seamless look. Most concealed showers are powered by a pump or combination boiler and offer greater flexibility in shower head placement compared to exposed systems. Before starting work, review the Part P building regulations that govern electrical work in bathrooms, as pumped systems require electrical connections.
Concealed systems include a thermostatic mixing valve that blends hot and cold water to maintain a consistent outlet temperature, protecting users from sudden temperature fluctuations. The shower head can be wall-mounted, on a riser rail, or overhead as a rainfall shower, depending on the design. Pipes run within the wall structure and emerge only at the valve connections and the shower head outlet. Understanding plumbing systems in buildings is essential before planning installation, as the layout must accommodate both supply and drainage requirements.
Building Regulations and Electrical Safety for Concealed Showers
Most concealed showers are power showers that require an electric pump to boost water pressure, and this pump needs electrical wiring. Electrical work in bathrooms is strictly regulated under Part P of the Building Regulations. It is illegal to carry out electrical wiring in a bathroom without appropriate qualifications or to have such work done by someone not registered with a competent person scheme. Any pump or control unit must be installed outside the bathroom splash zones or be suitably IP-rated for installation within those zones. The pump should be located in an accessible area, such as an airing cupboard or under the bath, where it can be maintained without breaking into the tiled wall finish.
Before installing a concealed shower, consider the water pressure available in your home. Gravity-fed systems with a cold water tank in the loft typically provide lower pressure and may require a pump to achieve a satisfactory shower experience. Combination boiler systems usually provide mains-pressure hot water and may not need a pump, but the flow rate must be checked against manufacturer specifications. The pipework size and routing also affect performance. The table below shows typical water pressure requirements for different shower configurations.
| Shower Type | Minimum Pressure | Typical Flow Rate | Pump Required? |
|---|---|---|---|
| Gravity-fed concealed | 0.1 bar | 8 12 litres/min | Usually yes |
| Combination boiler concealed | 1.0 bar | 12 18 litres/min | Usually no |
| Pumped concealed shower | 0.5 bar inlet | 15 25 litres/min | Yes, dedicated pump |
| Thermostatic bar mixer | 0.5 bar each | 10 16 litres/min | Depends on system |
Once you confirm that your water supply and electrical setup are suitable, plan how the pipework will be hidden from view. The most common methods involve building a false wall in front of the existing wall or notching pipes into existing studwork.
Concealing Pipework Behind a False Stud Wall
The simplest and most effective way to conceal pipework for a shower, toilet, basin, or towel rail is to build a false wall in front of the existing wall. Construct a timber stud frame that stands away from the original wall, run the pipes within the cavity, and cover the frame with plasterboard or cement board before tiling. A cavity of 75 mm to 100 mm is usually sufficient for 15 mm supply pipes, a 22 mm shower waste, and the shower valve bodies. For guidance on constructing the frame, see timber stud partition walls.
When building the false wall, follow these key steps:
- Fix bottom and top plates to the floor and ceiling using appropriate fixings, ensuring the frame is perfectly vertical and level.
- Install vertical studs at 400 mm or 600 mm centres depending on the plasterboard thickness and tile weight.
- Cut noggins horizontally between the studs to provide fixing points for shower valve brackets and pipe clips.
- Run the hot and cold supply pipes within the cavity, clipping them to the studs at regular intervals to prevent movement and noise.
- Fit a sturdy backboard through which the copper tails pass, ensuring they emerge at exactly the right position for the shower valve.
A well-built false wall also provides a convenient chase for running pipes to other bathroom fixtures. You can tee off the hot and cold feeds to supply the bath, basin, towel rail, and even washing machine connections in an adjacent room. All pipes must be properly supported with rules for notching joists and clipping distances followed to prevent movement that can cause noise and stress on joints. The false wall method is particularly useful in rooms where the existing walls are solid masonry and cannot be chased deeply enough.
Routing Pipework Through Joists and Masonry Walls
Where a false wall is not practical, pipes can be routed within the existing wall structure. For timber stud partition walls, pipes can be notched into the studwork or holes drilled through the centre of the studs and noggins. Notch depth must not exceed one-sixth of the stud depth, positioned in the top or bottom third to minimise structural weakening. Holes must be at least 6 mm from the edge and should not exceed one-quarter of the stud width.
For pipes in solid masonry walls, chase a channel deep enough for a 15 mm pipe sleeved in a 22 mm pipe, clipped at 400 mm centres. Sleeving is essential because expansion and contraction from hot water can crack plaster or tiles if the pipe contacts the mortar directly. Fill the chase with sand and cement mortar or bonding plaster. If the wall will receive tiles or shower panels, finishing plaster is not required. See chasing walls for pipework for detailed instructions. Overhead pipes for an overhead rainfall shower can be notched into ceiling joists, following the same structural guidelines.
Pipes can also be hidden behind shower panels fixed to timber battens on the wall. This approach is faster than tiling and offers easy access if pipe repairs are needed in the future. When using shower panels, ensure the panel joints are properly sealed with waterproof silicone to prevent moisture from penetrating behind them. For connecting pipework, a range of compression and push fit fittings suits both copper and plastic piping systems.
Thermostatic Mixing Valves and Fast Fixing Kits
Two main types of thermostatic mixing valves are used in concealed shower installations: the concealed unit and the bar mixer valve. The concealed unit mounts inside the wall cavity with only the control knob and trim plate visible on the finished surface, providing the cleanest possible aesthetic. The bar mixer mounts on the wall surface and connects to the protruding pipe tails. While more visible, it is generally easier to install and maintain because the valve mechanism remains accessible without breaking into the tiled wall finish.
Many modern bar mixers include a fast fixing kit that connects to pipe tails in a single cut operation. These kits include a mounting bracket that secures the valve to the wall and pre-formed connections that reduce the need for precise pipe alignment. Fast fixing kits are available for most major shower brands and make installation significantly easier for the home improver. Copper pipes are typically joined using compression fittings or soldered joints. For flexible connections, Speedfit push fit plumbing offers a reliable alternative that requires no special tools or heat.
All pipe connections, whether compression, soldered, or push fit, must be pressure tested for leaks before the wall is closed up. Once testing is complete, the wall can be covered with cement board or tile backer board, followed by tiling. The concealed valve trim plate is fitted last, after tiling, to ensure a precise fit against the finished surface. Understanding plumbing pipe joints and connection methods is essential for achieving leak-free results that will last the lifetime of the installation.
Finishing the Wall and Fitting Shower Fixtures
Cement board or waterproof tile backer board should be used in the shower area, not standard plasterboard, as moisture can deteriorate plasterboard if it penetrates through the grout joints over time. Fix boards securely to the studwork, tape and seal joints with waterproof joint compound, and apply a tanking membrane over the entire shower area before tiling for additional moisture protection. This waterproofing layer provides an important safety barrier that protects the structure behind the tiles.
Mark the exact positions of pipe tails and valve bodies on the finished boards so tiles can be cut accurately around them. Use a tile hole cutter or angle grinder with a diamond blade for clean, precise holes. The valve trim plate covers minor imperfections in the tile cuts, but accuracy is still important for a professional finish. For the shower head arm, fix a support bracket to the studwork behind the wall to ensure the shower head is rigid and does not move during use.
After tiling and grouting are fully cured, fit the valve trim, control handle, shower head, and riser rail. Run the shower for several minutes and inspect all visible joints and connections for any signs of leakage. A concealed shower that is properly planned and executed provides years of trouble-free service and adds significant value to any bathroom renovation. The clean, hidden finish is one of the most desirable features in contemporary bathroom design, and achieving it correctly requires careful attention to building regulations, structural integrity, and waterproofing at every stage.