Deal with water coming through the ceiling

Stop a ceiling leak safely, relieve pressure without hitting hidden cables, dry the area, then patch it once it's fully dry.

WCE-01Turn off electrics near the leakIf water is dripping near a light fitting, socket or switch, turn that circuit off at the consumer unit, or turn the whole thing off if you're not sure which circuit it is. Don't touch any switch with wet hands. Do this before you do anything else, even before you deal with the water itself.

WCE-02Stop the water at the sourceTurn off the stopcock, usually under the kitchen sink, and check it fully closes. If you know exactly what's leaking - a toilet, a washing machine, a bath overflow - isolate that appliance's own valve too, so you're not without water for the whole house. Open a cold tap afterwards to drain pressure out of the pipes.

WCE-03Move belongings and protect the floorMove furniture, electrical items and rugs away from the wet patch. Lay a plastic sheet down and put old towels around the edges to catch drips.

1 each · Plastic dust sheet

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4 each · Old towels

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WCE-04Catch the waterPut a bucket directly under the wet patch or bulge. Don't stand directly underneath a sagging or bulging ceiling - it can collapse without warning once it's holding water.

1 each · Bucket, 10 litre

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WCE-05Work out what the ceiling is made ofRun a stud/joist detector or a magnet along the ceiling to find the line of joists - a magnet clicks onto screw or nail heads. Tap between those lines: a dull thud usually means solid material behind, a hollow sound means plasterboard on timber or metal joists. A tiny pilot hole tells you more - fine timber dust means timber joists, grey metallic swarf means metal joists, and a very hard, gritty resistance with no dust at all can mean a solid concrete ceiling, common in some flats. Lath and plaster (older houses, pre-1930s) feels slightly springy and uneven under tapping, with thin wooden strips just behind the plaster.

1 each · Stud/joist detector

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WCE-06Relieve pressure if the ceiling is bulgingCables and pipes can run almost anywhere in a ceiling void, including diagonally or outside the usual safe zones - a detector helps but doesn't guarantee it's clear, and a metal joist frame confuses cheap detectors further. Make sure your water is already off at the stopcock (step WCE-02) and the electrics near the area are off (step WCE-01) before you pierce anything. On plasterboard over timber or metal joists, find a gap between joists with your detector and push a bradawl or screwdriver point gently through the lowest part of the bulge, letting water drain into your bucket. On lath and plaster, do the same between the wooden laths rather than through one. Do not pierce a solid concrete ceiling yourself - that's a job for a professional, and a leak through concrete usually means something more serious happening above.

1 each · Bradawl

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WCE-07Let it drain fullyLeave the bucket in place until dripping stops completely, which can take a few hours. Empty and replace the bucket as needed, and pour the caught water away down a drain.

WCE-08Dry the room outOpen windows and run a dehumidifier or fans on the wet area for at least a day or two. Remove any wet carpet, underlay or loft insulation sitting directly above the damaged patch so it doesn't stay damp and grow mould.

1 day · Dehumidifier hire (per day)

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WCE-09Find and fix what actually caused itBefore you patch anything, work out what leaked above - an overflowing bath, a failed shower tray seal, a split pipe - and get that fixed properly, by a plumber if you're not confident. There's no point repairing the ceiling if the same leak happens again next week.

WCE-10Patch the ceiling once it's completely dryFor a single small pierced hole, fill it with a flexible ceiling filler once the area is bone dry, then sand smooth. For a larger sagging or stained patch, cut back to the nearest joists on each side and screw in a new piece of plasterboard: use 3.5x38mm drywall screws into timber joists at roughly 150mm centres, or self-drilling drywall screws if the joists are metal - never plain wood screws into metal, they strip straight through. Dot-and-dab isn't used on ceilings, so you won't meet it here; if the surface behind lath and plaster has crumbled badly, it usually needs a small area of new plasterboard rather than a patch of plaster.

RULES

1 tub · Ceiling filler/patching plaster

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1 each · Plasterboard offcut

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1 box · Drywall screws 3.5x38mm (box)

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KNOW THE RULES

If the leak damaged wiring in the ceiling void and you're doing more than a simple repair, new electrical work must comply with Part P of the Building Regulations. Get a qualified electrician to check and certify it.

WCE-11Check for mould and redecorateOnce the patch is dry, wipe the surrounding area with a mild fungicidal wash if you see any dark spotting. Repaint with a moisture-tolerant ceiling paint once everything is fully dry, and dispose of any wet, mouldy materials in your normal household waste.

1 bottle · Fungicidal wash

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1 litre · Moisture-resistant ceiling paint

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