Shower Leaking Through the Ceiling Below? What to Do First and Who to Call

If your shower is leaking through the ceiling below, do two things first: stop using that shower, and find out whether the water is coming from a pipe or through the tiled area itself. A pipe fault is a job for a plumber. Water seeping through the tiles, which is the more common cause, means the waterproofing behind them has failed, and that is a tiler’s job. Until you know which one you have, every shower you take is pushing more water into the structure. Here is how to work through it calmly and who to call for each.

Key takeaways

• Stop using the shower straight away. Each use feeds more water into the ceiling and joists.
• A burst or dripping pipe is a plumber’s job. Water passing through the tiles is a tanking failure and a tiler’s job.
• A slow stain with sound, dry pipes almost always means missing or failed waterproofing behind the tiles.
• Older Bromley and Beckenham terraces suffer fast once a floor void stays wet, so do not wait it out.
• The lasting fix is usually tiles off and proper tanking, not another bead of silicone.

A Beckenham wet room where the floor was tanked and laid to a proper fall before a tile went down. That hidden waterproof layer is exactly what is missing when a shower leaks into the room below. Wet room service

Why is my shower leaking through the ceiling?

A shower can leak through a ceiling for one of two broad reasons, and they need different people to fix them.

The first is a plumbing fault: a leaking waste connection under the tray, a loose compression joint on the supply, or a cracked pipe in the floor void. This tends to leak whether or not the shower is in use, or it produces a steady drip rather than a slow stain.

The second, and the one I am called out to far more often, is water passing through the tiled area itself. People assume tiles and grout keep water out. They do not. Cement grout is water resistant, not waterproof, and water moves slowly through it and through the tile joints over time. In a properly built shower there is a tanking membrane behind the tiles, a product such as Mapei Mapelastic, BAL Tank-it, or a Schluter Kerdi system, that catches that water and drains it away safely. If that membrane is missing or has failed, the water has nowhere to go but into the wall, the floor void, and eventually the ceiling below. I explain that hidden layer in more detail in what tanking is and why a shower needs it.

The tell is simple. If the grout and silicone look sound and the pipes are dry but the ceiling is still staining, the problem is behind the tiles.

Who do I call: a plumber or a tiler?

This is the question that trips most people up, because the obvious instinct is to call a plumber and a leak sounds like a plumbing word.

Call a plumber first if water is actively running, you can see or hear a pipe involved, or the leak happens even when nobody has used the shower. Stopping an active flow is the priority and that is plumbing work.

Call a tiler if the leak is a slow stain that appears during or shortly after showering, the pipework checks out dry, and the silicone or grout is suspect or the shower is simply old. Waterproofing a wet area, forming falls, and tiling are a tiler’s trade, not a plumber’s, and a plumber re-tightening a fitting will not fix a tanking failure. For the underlying diagnosis, my guide on whether it is the grout, the silicone, or the tanking walks through how to tell the three apart before anyone starts pulling tiles off.

If you genuinely cannot tell, start with whoever can see it soonest and ask them to be honest about whether it is their trade. A good tradesperson will tell you when a job belongs to someone else.

What should I do right now to limit the damage?

Before anyone arrives, a few minutes of sensible action saves a lot of repair.

• Stop using the shower. This is the single most useful thing you can do. Use another bathroom if you have one.
• Clear the ceiling area below. Move furniture and electronics out from under the stain in case it gives way.
• Watch the light fittings. Water near a ceiling rose or downlight is a real shock risk. If the ceiling is wet around a fitting, turn off that lighting circuit at the consumer unit and leave it off.
• Do not pierce a bulge yourself unless it is about to fail. A sagging, water-filled ceiling can drop suddenly. If it is clearly bulging and you must relieve it, do it from the side with a bucket ready, power off, and stay clear.
• Take photos and note when it leaks. Whether it only stains during a shower or also overnight is exactly the information a tiler or plumber needs, and it helps any insurance claim.

Why do older Bromley and Beckenham terraces leak like this?

A lot of the housing stock around here is Victorian and Edwardian terraces with suspended timber floors and lath-and-plaster or early plasterboard ceilings. Those floor voids are full of joists that do not tolerate sitting wet. A shower that was tiled directly onto plasterboard with no tanking, which was standard practice for decades, will let water through the grout into that timber, and the first you see of it is a brown ring on the ceiling of the room below.

It is worth being clear that this is not bad luck. It is a build that was never waterproof to begin with. When I strip these out across Bromley and the surrounding terraces, the tiles often look fine on the face while the board behind them is soft and black. That is why a quick regrout so rarely holds: the water is already getting past the surface every time. The honest decision between a patch and a proper redo is the same one I cover in regrout or retile, and persistent dark staining usually points the same way, as I set out in the piece on black mould in shower grout.

What does the real fix involve?

If the cause is a tanking failure, the lasting repair is to take the tiles off the affected area, check and dry the substrate, replace any water-damaged board, install a proper waterproof membrane, and re-tile. On the floor of a true walk-in or wet area that also means forming the falls correctly so water runs to the drain. It is more work than a bead of silicone, but it is the difference between a shower that is dry for decades and one that quietly rots the floor again.

Where the leak is local and the rest of the installation is sound, the repair can be smaller. The only way to know which you are facing is to have someone open it up and look. If you are in Beckenham, the Beckenham wet room and waterproofing service page sets out how I approach these jobs locally.

A leak through a ceiling reads as a crisis, and it does need acting on, but it is a known problem with a known fix. Stop using the shower, work out whether it is a pipe or the tiles, and get the right trade in.

See:

• Leaking shower: is it the grout, sealant, or tanking?
• What is tanking and why a shower needs it
• Regrout or retile: which does your shower actually need?

If your shower is leaking into the room below and you want it looked at properly rather than patched, get in touch for a written quote. I will tell you honestly whether it is a small repair or a tiles-off job, and I will not sell you the bigger one if you do not need it.