How do I fit a smoke alarm?

Fitting a battery smoke alarm is a ten-minute job with two screws, and the only decisions are where to put it and what type. Both matter more than the fitting: an alarm in the wrong place either fails to detect a fire or false-alarms until someone disables it.

Safety

What you'll need

• Smoke alarms
• Heat alarm for the kitchen
• Drill and screws
• Step ladder
• Cable detector (optional)

Step by step

1. Plan the positions: at least one per floor, in hallways and on landings.Those are the escape routes. An alarm that wakes you and lights the way out is doing its job.
2. Mount on the ceiling, near the centre of the space, at least 30cm from any wall or light fitting.Smoke rises and spreads across the ceiling. Corners and edges are dead air.
3. Use a heat alarm rather than a smoke alarm in the kitchen.Smoke alarms in kitchens false-alarm constantly, which leads to them being disabled.
4. Avoid bathrooms, and avoid positions directly above a cooker or a heater.Steam and heat both trigger false alarms.
5. Check for cables, then drill and fix the base plate.Two screws. The base plate usually has slotted holes so you can level it.
6. Fit the battery or connect the sealed unit, then twist the alarm onto the base.Many will not latch onto the base unless a battery is fitted, which is a deliberate design feature.
7. Test it with the test button.It should be loud enough to wake someone sleeping with the door closed.
8. Write the replacement date on the alarm.Ten years from now. The sensor degrades regardless of the battery, and nobody remembers otherwise.

Tips

• Interlinked alarms, where one sounding triggers all of them, are substantially safer in a multi-storey home. Radio-interlinked battery models avoid any wiring.
• Requirements differ across the UK — Scotland in particular has specific rules on interlinked alarms in every home. Check the current rules where you live, especially if you let property.
• Ten-year sealed-battery alarms remove the annual battery job entirely and are worth the higher purchase price.

Common mistakes

• Fitting a smoke alarm in the kitchen — Constant false alarms lead to it being disabled, which is far more dangerous than not having one.
• Mounting in a corner or against a wall — Smoke spreads across the ceiling and corners are dead air. It delays detection.
• Fitting one alarm for a whole house — An alarm on the ground floor may not wake someone asleep upstairs with the door closed.

Questions people ask