Leaking Shower: Common Causes and How They Are Fixed

Signs the shower is leaking

Not every leak drips. Many are slow seepage that only shows over weeks. Watch for these signs, particularly after long showers.

• A brown ring or bubbling paint on the ceiling below
• Grout that stays dark long after the shower has dried
• Silicone that has gone black, split or come away from the tray
• Loose or hollow sounding tiles near the tray
• Flooring or skirting outside the enclosure that is swelling

The usual causes, in the order we check them

Failed silicone between the tray and the wall is the most common cause. Tray movement, cleaning chemicals and age all break the seal, and water runs straight behind it. Next is porous or cracked grout, which lets water soak into the wall behind. After that we look at the waste: a loose trap, a perished seal or a waste that was never bedded properly under the tray.

Less often, the leak is in the pipework or the shower valve itself. That kind of leak usually happens whether or not the shower is running, which is a helpful clue. Finally, a tray that flexes because it was not fully supported will keep breaking every seal you put on it.

A safe way to narrow it down

You can help us diagnose it. With the shower off, check whether the ceiling stain still grows; if it does, suspect the supply pipework. Then run water only onto the tray with a hand held head, keeping it off the walls; a leak now points to the waste or tray seal. Finally, spray only the walls. A leak on that test suggests grout, tiles or the wall waterproofing.

If water is near light fittings below, turn off the electrics to that circuit and keep people out of the room. That is when to use our 24/7 call outs for leaks and make safe work.

What a proper repair involves

A fresh bead of silicone over old silicone is not a repair. The old sealant has to be cut out completely, the joint cleaned and dried, then resealed with a sanitary grade product. Grout can be raked out and renewed. A waste can often be reached from below or by lifting the tray.

Where water has been getting behind the tiles for a long time, the board behind may be soft. At that point the lasting fix is to strip the affected area, let it dry, renew the waterproofing and retile. It is more work, but it is the difference between fixing the leak and chasing it every few months.

Do not forget the damage below

Once the leak is stopped, the ceiling or floor underneath needs attention too. Because plumbing, plastering and decorating are all trades we do ourselves, we can repair the shower and the ceiling below in one job. Our guide to water damaged ceilings explains that side of the work in detail.