Mains-operated fire alarm

[SleepBecomesHim321]

Evening all, grateful for any advice here.

We're almost at the end of a building project in which we'll have gained one room by converting a gsrage. The building control person has said we need to install a mains-operated fire alarm in circulable areas on each floor (there are three floors).

Has anyone had this done and is able to provide a very approximate ballpark cost? How disruptive is this work? We'll obviously get quotes but I'd like to be braced as we were unprepared for this.

Thanks in advance.

We had them wired in every room as part of a loft conversion. Can't advise on cost as obviously included in ours. They just cut a hole in the ceiling in every room so there was some bits of small plasterboard etc to clear up. They are LOUD!!!!!!! My DH has set the kitchen one off when cooking and they all go off. It terrifies the cats and children!

Hard wired smokes aren’t particularly expensive. I paid about £80 each fitted. And the fitting is super easy if your ceiling is board and joists

We had two fitted in a rental house last year and I think they cost £250 for the two as part of a whole house rewire. You'll never have to change the battery again and it's safer.

Is there not a risk that they won't go off if the fire starts due to an electrical fault? Apologise if this is a silly question; I don't know anything about the technicalities of house fires.

The ones in my flat have a battery backup that charges off the mains in case of power cut. I think that's probably standard as loss of power is possible during a fire.
If you ask whoever you get to install them they should be able to advise if your alarms will have a backup

Thank you very much - this is all very helpful! Can I ask two more things: is it very disruptive of decor? In other words, will we need to redecorate everywhere afterwards as there'll be new wiring everywhere? Or is it just a case of putting an alarm vaguely near a ceiling light (thus only requiring a little bit of extra wiring in each place)? Thanks again.

it can be spurred off a ceiling light but you need to take into account that it will be reliant on that circuit. So if the light circuit fails so will your smokes. It can have its own circuit but that is more disruptive with regards to installation and making good.

Sorry finished too soon. If it has battery back up though it doesn’t really matter what circuit it’s on

Thanks again! Final Q now I promise: does anyone have a definition of what counts as a "circulable area"? That's where we've been told to install them. I assume that means hallways/landing but not in bedrooms themselves. Will obv check with building inspector but he's on holiday for a fortnight now!

Ours had to be in all rooms except the bathroom. So each bedroom, hallway and kitchen. The building inspector even ummed and ahhed over a lobby area that has nothing in it but a cupboard and is open to the hall (which has one!)