Welling Kitchen Ceiling Stain Under the Bathroom: Causes

A stain on the kitchen ceiling under a Welling bathroom is almost always one of four things: the seal round the shower tray or bath, the waste pipe under the bath or shower, the connection between the toilet and the soil pipe, or a supply pipe under the bathroom floor. Watch when the stain gets worse. After showers points to the shower; after baths points to the bath waste or overflow; after flushing points to the toilet; all the time, even overnight, points to a pressurised pipe. Find the cause before you paint over it.

Why this is the Welling leak

Welling, DA16, was built almost entirely between the wars, and its 1930s semis share a layout. In a great many of them the bathroom sits directly above the kitchen. Nearly every one of those bathrooms has been refitted at least twice since, and each refit was usually built on top of the original pipe runs and joints underneath. The joint between the bathroom floor and the kitchen ceiling is where all of that history meets, and it is the commonest ceiling stain in the postcode.

Hard water adds to it. Welling sits in the Bexleyheath supply zone, around 359 mg/l on Thames Water’s figures, the hardest in our area and well into the “very hard” band. Scale builds up in traps and wastes, slows them down, and the water that sits there finds the weakest seal.

How do I work out which one it is?

The shower test

Do not use the shower for a day. Then run the shower for five minutes with the spray aimed only at the tray, not the walls. Check the ceiling. Then, another time, spray only the walls and the corners. If the stain spreads after spraying the tray, suspect the tray waste or the seal between tray and wall. If it spreads after spraying the walls, the grout or silicone is letting water behind the tiles.

The bath test

Fill the bath, then let it drain while you watch the ceiling. A leak that appears only as it drains points to the waste or its connection. A leak when the bath is full up to the overflow points to the overflow fitting.

The toilet test

Flush a few times in a row and check the ceiling. A leak after flushing points to the pan connector, the flexible or plastic sleeve that joins the toilet to the soil pipe, or to the cistern-to-pan seal.

The overnight test

If the stain gets bigger when nobody has used the bathroom, it is a pipe that is always under pressure: the cold feed, the hot feed, or a heating pipe. Check the water meter with everything off. If it moves, that confirms it.

What can I check myself?

1. Look at the silicone round the bath and shower tray. Black, cracked or lifting silicone lets water through.
2. Press gently on the shower tray. If it flexes or creaks, the seal will be breaking every time someone stands in it.
3. Look at the grout lines, especially in the corners and along the bottom row of tiles.
4. Take off the bath panel and look underneath with a torch while someone runs the taps and drains the bath.
5. Look behind the toilet at the pan connector and the cistern for drips or staining.
6. Check the small isolating valves on the pipes to the toilet and basin for any dampness.

When does this become urgent?

A brown stain that dries out between showers is a warning. A stain that stays wet, grows, or starts to sag is an emergency in the making. Plasterboard ceilings take water for a long time and then fail suddenly.

• Switch off the lights in the kitchen at the consumer unit if the stain is near a fitting or water is dripping from it.
• Stop using the bathroom until you know what is causing it.
• Turn the stopcock off if the leak continues when the bathroom is not in use.
• Do not pierce a bulging ceiling yourself. Put a bucket under it and keep people out of the way.

Why fix the cause before decorating?

Stain block paint will hide a mark, but if the leak is still there the stain comes back and the plasterboard keeps softening. The order is: find the source, fix it, let the ceiling dry fully, then decide whether it needs patching or replacing, then stain block and paint. A ceiling that has been wet for weeks may also be growing mould above the board.

Is it covered by insurance?

Many policies cover the damage caused by an escape of water, such as the ceiling, but not the repair to the thing that leaked, such as a worn shower seal. Some also exclude damage from leaks that have gone on gradually. It depends on your policy. Take photos before anything is fixed.

What if the leak is on the heating?

Most Welling houses had their heating added after they were built, often with pipes in the solid front-room floor, but in the bathroom the heating pipes to the radiator or towel rail run under the floorboards too. A dropping boiler gauge plus a ceiling stain points that way. We trace and repair the pipework; anything on the boiler itself needs a Gas Safe registered engineer.

New Eltham’s semis have a very similar layout, and our guide to water through the ceiling in a New Eltham semi covers what to do when it is already dripping. More about DA16 on our Welling page.

Need a plumber now?

If the stain is wet, growing or sagging, Call 07868 281022. Tell us your postcode, what the stain does after showers, baths or flushes, and whether the water is off. We handle water through the ceiling in Welling and water leaks across DA16, including East Wickham and Falconwood, and we agree the price with you before any work starts.