Smoke Alarm Placement Rules for Rental Properties in England

The One-Per-Storey Rule and Why Position Matters

The Smoke and Carbon Monoxide Alarm (England) Regulations 2015 (as amended 2022) require at least one smoke alarm on every storey that contains a room used wholly or partly as living accommodation. "Storey" takes its ordinary meaning; government guidance says a mezzanine floor is not considered a storey for these regulations. Basements and converted lofts with living accommodation are generally treated as separate storeys.

The regulations do not specify where on a storey an alarm must be placed. Government guidance says to follow the manufacturer's instructions and recommends, in general, a ceiling position in a circulation space such as a hall or landing. An alarm in a bedroom or living room may leave the circulation space less well protected, even though the regulations set the duty by storey rather than by room.

CO alarms follow a different trigger: they go in any room used wholly or partly as living accommodation that contains a fixed combustion appliance (gas boiler, oil boiler, wood-burning stove, solid-fuel fire), excluding gas cookers. Follow the manufacturer's instructions; in general, position the alarm at head height on a wall or shelf, about 1 to 3 metres from the appliance.

Hallways, Landings, and Stairwells

For a typical two-storey house, you need at least two smoke alarms: one on the ground-floor hallway ceiling and one on the first-floor landing ceiling. If the stairwell is open to the landing above, the upstairs alarm still goes on the landing — not on the stair slope, where rising heat creates false readings.

Place the alarm centrally on the ceiling, at least 300mm from any wall or light fitting. Keep it away from kitchens (steam and cooking fumes trigger nuisance alarms) and bathrooms (moisture). If the hallway is long — more than about 7.5 metres — consider a second alarm at the far end, though the regulations only mandate one per storey.

Converted Lofts

A loft conversion containing a bedroom, study, or playroom is generally treated as a separate storey with living accommodation. You need a smoke alarm on the loft level; government guidance recommends following the manufacturer's instructions and, in general, placing it on the ceiling in a circulation space such as the landing or hallway at the top of the stairs.

If a boiler is in a loft room used as living accommodation, the alarm regulations require a CO alarm in that room. Installing or replacing a fixed combustion appliance may also trigger separate requirements under Approved Document J. In practice, many councils ask for interlinked alarms between the loft and the storeys below, especially in HMOs, though the national minimum under SI 2015/1693 only requires one per storey.

Basements and Below-Ground Flats

A basement that contains a room used as living accommodation — a bedroom, living room, or kitchen — is a storey for regulatory purposes. The smoke alarm goes on the basement ceiling in the circulation space nearest the stairs.

An unconverted cellar used solely for storage does not trigger the smoke alarm duty. Under the alarm regulations, a CO alarm is required only in a room used wholly or partly as living accommodation that contains a fixed combustion appliance. A new or replacement appliance may separately trigger requirements under Approved Document J.

Mezzanine Levels and Split-Level Floors

Government guidance says a mezzanine floor is not considered a storey for the alarm regulations, even if it functions as a living or sleeping space. Additional detection may still be appropriate or required under building-control, licensing, or fire-risk requirements. Follow the alarm manufacturer's instructions for any extra detector and its mounting position.

Split-level properties (half-landing layouts common in 1960s and 1970s builds) can create ambiguity because the regulations do not define "storey." Government guidance says to use the ordinary meaning and specifically excludes a mezzanine floor. For a borderline layout, check with the local housing authority or building control; extra alarms can provide added protection. A penalty of up to £5,000 may follow if a landlord fails to comply with a remedial notice.

Open-Plan Layouts and Studio Flats

In a studio apartment with an open-plan kitchen-living area, a single smoke alarm placed centrally in the circulation space (the entrance hallway or near the front door) satisfies the statutory minimum. Avoid placing the smoke alarm directly above the cooking area — a heat alarm (BS 5446-2) works better there, though it does not replace the mandatory smoke alarm on that storey.

If the kitchen includes a gas boiler or solid-fuel range cooker, a CO alarm is required. Follow the manufacturer's instructions; in general, place it at head height on a wall or shelf, about 1 to 3 metres from the appliance. A kitchen with only a gas hob and no other combustion appliance is exempt from the CO alarm duty — gas cookers are explicitly excluded by Regulation 4(1)(a)(ii).

Enclosed Boiler Cupboards

When a fixed combustion appliance is inside a small cupboard off a living-accommodation room, follow the alarm manufacturer's instructions and Approved Document J where it applies. General government guidance recommends placing a CO alarm at head height on a wall or shelf, about 1 to 3 metres from the source; avoid placing it where an enclosed cupboard or other obstruction could prevent the alarm being heard.

What This Means for Your Next Check-In

Getting placement right before the tenancy starts helps avoid a remedial notice requiring corrective work within 28 days. A penalty of up to £5,000 can follow if you then fail to comply with the notice.

Our Smoke and CO Alarm Compliance Guide includes a storey-by-appliance mapping worksheet that walks you through every level and combustion source in your property, so you document exactly where each alarm goes and why. It takes the guesswork out of unusual layouts — lofts, basements, mezzanines, open-plan studios — and gives you a dated record for your files.

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