Hang a replacement radiator on a lath and plaster wall — HomeGraft

Remove your old radiator, find safe fixing points behind the wall, then hang and reconnect a replacement safely.

RL-01Turn off the heating and set upTurn off the central heating and let it cool for at least an hour - water inside a radiator can scald. Lay dust sheets over the floor and any nearby furniture, and clear a working space around the radiator. Get your tools together so you're not hunting for them with a leaking pipe in your hand.

1 each · Dust sheet

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1 each · Bucket

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1 each · Adjustable spanner

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1 each · Radiator bleed key

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1 roll · PTFE tape

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RL-02Drain and remove the old radiatorClose both valves fully - the wheel-head valve and the lockshield valve. Count how many turns you use to close the lockshield, so you can open the new one by the same amount later. Put towels and the bucket under each valve, loosen the nuts to disconnect the radiator, and let it drain. Lift it off the old brackets, stand it on towels to finish draining, then unscrew the brackets from the wall.

2 each · Old towels

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RL-03Work out what's behind the lath and plasterLath and plaster is thin timber strips nailed either straight to solid masonry or across a timber stud partition, with plaster keyed through the gaps - it's never fixed to metal studs or dot-and-dab, which are both modern plasterboard methods. Tap along the wall: a dull, slightly springy sound usually means timber studs behind, a hard dead sound usually means solid masonry. Drill a small 3mm pilot hole low down in an inconspicuous spot - brick dust means masonry, timber shavings mean a stud or noggin. If part of the wall has been patched with modern plasterboard after rewiring, check with a magnet: it grips a steel stud but not timber.

1 each · 3mm drill bit

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RL-04Check for cables and pipes before you drillOld walls hide surprises, so run a cable and pipe detector over the area you've marked, then still assume something could be there - detectors miss cables that are deep, in metal conduit, or outside the usual safe zones. Before drilling, find your stopcock (usually under the kitchen sink) and check it turns freely, so you can shut the water off fast if you hit a pipe. If you have any doubt at all, isolate the circuit at the consumer unit before drilling.

1 each · Cable and pipe detector

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RL-05Mark and level the new bracket positionsHold the new radiator's fixing centres against the wall, or measure them from the box, and mark the bracket positions in pencil. Use a spirit level to keep both brackets level and to set the radiator the usual 100-150mm off the floor, clear of the skirting board. Double-check the spacing matches the radiator's fixing lugs before you drill.

RL-06Fix brackets into masonry behind the lath and plasterIf your pilot hole gave brick or block dust, drill through the plaster and lath and on into the masonry with a 7mm masonry bit, going at least 45mm into solid material behind the lath. Fit a wall plug rated for a heavy load, then drive in a 75mm heavy-duty screw so it bites fully into the masonry, not just the plaster skim. Never rely on lath and plaster alone to hold a radiator bracket - it's too thin and will crumble under the weight.

1 pack · Heavy-duty wall plugs

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1 pack · 75mm heavy-duty screws

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1 each · 7mm masonry drill bit

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RL-07Fix brackets into a timber stud behind the lath and plasterIf your pilot hole showed timber shavings, find the centre of the stud or noggin with a bradawl or a couple of small test holes either side of your mark. Drill a 4mm pilot hole through the plaster, lath and into the stud, then drive a 75mm coach screw into the centre so at least 40mm bites into solid timber. If you instead find steel swarf from a modern metal-stud patch, never use a wood screw or plain wall plug - it strips straight through 0.5mm steel. A metal stud alone won't hold a radiator's weight or the pull as it fills with water, so fit a timber noggin between the studs first, or fix through to the masonry behind.

1 pack · 75mm coach screws

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1 each · 4mm drill bit

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1 each · Timber noggin offcut

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RL-08Fit and check the bracketsScrew both brackets to the wall using the fixings for your wall type, checking each one is level before moving to the next. Give each fixing a firm tug once it's in to make sure it doesn't move in the wall. Don't hang the radiator until you're confident both brackets are solid.

RL-09Hang the radiator and reconnect the valvesLift the radiator onto the brackets and check it sits level and square. Wrap fresh PTFE tape clockwise around the valve tail threads, then reconnect both valves by hand before nipping them up with the spanner - don't overtighten, as this can crack old fittings.

1 roll · PTFE tape

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RL-10Refill the system and bleed the radiatorOpen both valves slowly and let the radiator fill. Use the bleed key on the top bleed valve to let trapped air escape, closing it as soon as water dribbles out steadily. Check your boiler's pressure gauge and top up following the boiler's own instructions if it's dropped low.

RL-11Check for leaks and tidy upRun the heating and check every joint and both valves for drips after 30 minutes, then again after a few hours. Wipe up any water straight away and lift the dust sheets once everything's dry. Take the old radiator to a metal recycling point or your local recycling centre.

1 each · Cloth

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