If your block has any shared gas supply (a communal boiler, shared heating, gas meter for common areas) the law requires an annual safety inspection by a Gas Safe registered engineer. Cheap and quick, but unforgiving on the calendar.
The duty only kicks in where gas is shared at the building level. Most modern blocks (and many converted Victorian buildings) have individual gas meters per flat with no communal element. If that is your block, this page does not apply to you and you can move on. If you have communal gas, the inspection is annual, cheap, and quick.
For an annual safety check. £80 to £200 per appliance is typical. Simple single-boiler installations are at the low end. Multi-appliance plant rooms run higher.
Per appliance. The system is briefly interrupted while pressure tests and combustion checks run. Residents on a communal heating system may notice a brief interruption.
Hard cycle, not flexible. Certificate is valid for 12 months from the date of inspection. Set a calendar reminder for renewal 30 days before expiry.
What gets tested. Each gas appliance: heat input and pressure, flue and combustion, ventilation, safe operation devices, and visible pipework. The engineer issues a CP12 (Landlord/Homeowner Gas Safety Record) showing each appliance, the test results, and any defects coded as Immediately Dangerous (ID), At Risk (AR), or Not to Current Standards (NCS).
Pick the one that matches you.
The first question is scoping. Communal gas means any of: a shared boiler serving more than one flat, a communal heating system, a gas meter feeding common areas (lighting, hot water), or any gas pipework that crosses between flats and the freeholder's responsibility.
The duty is annual and unforgiving. An expired or missing CP12 is a live criminal offence and a live insurance issue.
What to do. Use the calculator below to budget. Use the supplier checklist for a Gas Safe engineer with commercial competence. Use the draft email for three quotes. Schedule the inspection within the next two weeks. Most engineers can attend within days.
Immediately Dangerous (ID) means the engineer should disconnect the appliance with permission. At Risk (AR) means it must be repaired before the next use.
Cost scales mostly with appliance count. Small communal heating: cheap. Plant rooms: more.
You have selected zero communal gas appliances. The duty under the Gas Safety (Installation and Use) Regulations 1998 does not apply at the building level. Each flat's individual gas is the leaseholder's responsibility.
All figures are indicative ranges based on published rates checked April–May 2026. Always compare three written quotes for your specific building. Last reviewed for accuracy on the page legal-check date shown above.
Not every Gas Safe engineer can work on communal gas. The accreditation is per-appliance type. The wrong engineer cannot legally test a commercial boiler.
Specifies commercial Gas Safe competence and a CP12 per appliance. If the engineer cannot meet these, you have your answer.
If you discover during scoping that the building has no communal gas, no further action is required at the building level. Each flat's gas safety remains the leaseholder's responsibility.
An annual gas safety check is small money in the context of the service charge. Recovery is straightforward. Major plant work (boiler replacement, communal pipework) is a different conversation and frequently crosses the £250-per-leaseholder qualifying-works threshold.
Include the CP12 in your annual service charge budget. Recover via your usual quarterly or half-yearly demands. Attach the invoice to the year-end accounts. The Section 21B summary of rights must accompany every demand.
If the reserve fund is empty and the CP12 is overdue, issue a one-off demand specifically for the inspection. The demand must include the Section 21B summary or it is not legally enforceable. Safety-led demands are normally well received.
The annual check itself is well below the £250 per leaseholder threshold for any normal block. What can trigger consultation is significant remedial work (replacing a communal boiler, redoing pipework). Major plant replacement can run tens of thousands and almost always requires Section 20 consultation. See the Section 20 process.
Keep every CP12 on file permanently. Set the next-year reminder 30 days before expiry. Notify the buildings insurer of any annual renewal lapse and any ID/AR finding.
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Read the Hafer Road case study →BLOCK-iQ logs your CP12 expiry, flags renewal 30 days out, and pre-fills the engineer email with your building's appliances. No more discovering the certificate expired three months ago. No more last-minute scramble.