Choose where to put smoke and carbon monoxide alarms

Work out where UK rules and common sense say alarms should go, then fit them safely to any wall or ceiling type.

AB-01Check what the rules actually requireIn England, the Smoke and Carbon Monoxide Alarm (England) Regulations 2022 require a smoke alarm on every storey with a room used for living accommodation, and a carbon monoxide (CO) alarm in any room with a fixed combustion appliance, such as a boiler, gas fire or wood burner (not gas cookers). This is a legal duty for private landlords now. Scotland has a stricter standard that also covers owner-occupied homes. If you own your home in England, you're not legally bound, but fitting to the same standard is cheap and sensible.

RULES

KNOW THE RULES

Smoke and Carbon Monoxide Alarm (England) Regulations 2022 set minimum requirements for rented homes. Scotland's tolerable standard applies to all homes, rented or owned, since February 2022. Check current rules for Wales and Northern Ireland separately, as they differ.

AB-02Plan where each alarm goesFit a smoke alarm on every storey, ideally in the hallway or landing where you'd smell smoke early, and within 3m of bedroom doors if you can. Use a heat alarm, not a smoke alarm, in the kitchen — cooking steam sets smoke alarms off constantly. Fit a CO alarm in any room with a boiler, gas fire, wood burner or other fuel-burning appliance, and in the room above or next to a solid fuel appliance too if it backs onto living space.

1 each · Interlinked smoke alarm (mains or battery)

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1 each · Heat alarm for kitchen

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1 each · Carbon monoxide alarm

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AB-03Get the exact position rightFor ceiling-mounted smoke and heat alarms, keep the alarm at least 300mm from any wall and 300mm from a light fitting, so smoke reaches it properly. For a wall-mounted CO alarm, follow the manufacturer's instructions — most want it 150-300mm below the ceiling, roughly 1-3m horizontally from the appliance, and never crammed into a corner where air doesn't move. Mark the spot lightly in pencil before you check what's behind it.

AB-04Work out what you're fixing intoMost UK ceilings are plasterboard on timber joists, but flats and newer builds sometimes use metal stud partitions and ceiling grids, so don't assume. Run a magnet or stud detector along the line where you plan to drill — a line of screw heads or a strong magnetic pull means timber studs with plasterboard screwed on; a hollow, even sound with no magnetic pull often means metal studs or a void behind dot-and-dab. Drill a small 2mm pilot hole and look at what comes out: pale timber dust means a joist or stud, fine grey metal swarf means a metal stud, and hard grey-white dust with no resistance for the first 10-15mm means dot-and-dab or solid masonry behind a plaster skim.

1 each · Stud detector

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AB-05Check for cables and pipes before you drillCables and pipes can run almost anywhere in a wall or ceiling, not just where you'd expect. Use a cable and pipe detector over your marked spot, but treat the result as a guide, not a guarantee — detectors miss cables that are deep, in metal conduit, behind metal-backed plasterboard, or running outside the usual safe zones, and a metal stud frame will confuse a cheap detector further. Find your stopcock now, usually under the kitchen sink, and check it turns freely, so you can shut off the water fast if you hit a pipe. If you have any doubt, switch off the relevant circuit at the consumer unit before drilling, and don't drill at all until you're confident there's nothing live or wet in the way.

1 each · Cable and pipe detector

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AB-06Fix the mounting plate — method depends on what's behind itSolid brick or block: drill a 6mm hole to 30mm deep, insert a wall plug, and drive in a 25mm screw. Plasterboard on timber joist or stud: drill a 2mm pilot hole into the centre of the joist and use a 25-30mm wood screw directly — no plug needed. Plasterboard on metal stud: never use a wood screw or plastic plug, they strip straight through 0.5mm steel; use a self-drilling metal-stud screw made for the job, or a snap-toggle if you're fixing between studs into bare plasterboard. Dot-and-dab: use a fixing long enough to pass through the plasterboard and the adhesive void (usually 60-70mm) into the solid masonry behind, or a plasterboard fixing rated for a light load if you can't reach the wall. Lath and plaster: make a fine pilot hole with a bradawl to avoid cracking the old plaster, and fix into a lath timber where you can find one, or use a spring toggle rather than an expanding plug, which can crack brittle plaster.

1 each · Masonry drill bit, 6mm

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1 pack · Wall plugs, pack of 20

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1 pack · Wood screws, 25-30mm, pack

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1 pack · Self-drilling metal-stud fixings, pack

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1 pack · Spring or snap toggle fixings, pack

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1 pack · Long dot-and-dab fixings, pack

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1 each · Bradawl

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AB-07Fit the alarm, test it and tidy upTwist the alarm onto its mounting plate until it clicks, fit the battery if it's battery-powered, and press the test button until it sounds. If your alarms are interlinked, test that one going off triggers the others too. Vacuum up any dust or plaster debris, wipe down surfaces, and note the fitting date on the alarm or in your diary so you remember when to replace the battery or the whole unit.

1 pack · Alarm batteries (if not mains-wired)

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1 each · Dust sheet

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