Electrics and gas
A carbon monoxide alarm sits on a bookshelf across the room from an open flue. What siting check has the home survey not treated as a Gas Safe inspection?
The home survey has not treated that alarm position as a Gas Safe inspection. A carbon monoxide alarm on a bookshelf across the room from an open flue is a siting observation the surveyor can make. It is not a check of the sensor, the expiry or the flue. Gas Safe inspection is a separate activity. The survey has not certified the alarm, the flue or the appliance. The note is where the alarm was sitting.
Last reviewed 24 October 2026. Written for buyers in England and Wales unless this answer says otherwise. No named surveyor has signed this page. It is general guidance, not a report on your house, and not legal advice.
What is the fuller explanation?
An open flue needs the products of combustion to leave the room, and an alarm is there to warn if they do not. Where the alarm sits relative to that flue is something a gas engineer judges against the appliance in front of them. A home survey can say the alarm was across the room on a shelf. It cannot sign that position off, and it cannot fail it as a Gas Safe inspector would. No combustion test was done. The flue was not swept.
Ask a Gas Safe engineer to check the alarm siting with the open-flue appliance, and keep that certificate, if one is issued, separate from the home survey. Tell the solicitor the survey has not certified the alarm. Do not move the alarm onto a different shelf and call the question closed without that inspection. The bookshelf note is not a gas-safety pass.
What should you ask your surveyor?
- Did you note the alarm on a bookshelf rather than certify its siting?
- Was any Gas Safe inspection of the open flue outside this visit?
- Was the alarm sensor itself left untested?
What are the typical next steps?
- Read the note as where the alarm was sitting, not as a gas certificate.
- Ask a Gas Safe engineer to check the alarm with the open flue.
- Do not treat a moved alarm as a completed siting inspection.
Costs vary with the building and with who you instruct. Where this page does not cite a published figure, ask the surveyor, a relevant specialist, or your solicitor for a written quote. Do not treat a forum average as the price.
Also asked about this
If the alarm beeps when you press the button, is the siting passed?
No. A button test, if you do one, is not the home survey and not a Gas Safe inspection. The survey has not certified the position across the room from the open flue. Pressing a button does not check where the alarm sits relative to that flue.
Does a capped fireplace remove the alarm note?
Only if the open flue is truly out of use, which the survey has not certified. An alarm on a bookshelf was still only observed. No Gas Safe siting check was carried out. A cap, if one is there, was not a gas-safety inspection of the alarm or the flue.