Extension Built Over Gas Service And Flue Leads To Prosecution


Mon 17th Aug 2026 by HS Hub

Extension Built Over Gas Service And Flue Leads To Prosecution

Extension Built Over Gas Service And Flue Leads To Prosecution


Feature by HS Hub | Mon 17th Aug 2026

Brief Summary

A domestic extension was constructed over existing gas service pipework and without relocating a boiler flue. Repeated warnings from building control were not acted on, construction phase planning was absent, and the gas installation was found immediately dangerous. The case shows the practical consequences of poor planning and weak coordination over live services.

What Was The Incident?

Work to build a rear extension began in January 2024 and proceeded without relocating the property gas service pipework or moving the boiler flue. A building control inspection in May 2024 found the boiler flue terminating inside the extension while the boiler remained in operation. The gas network operator declared the installation immediately dangerous and isolated the supply. The failures identified included lack of written construction phase plans when acting as principal contractor, failure to respond effectively to repeated building control warnings, and inadequate arrangements to identify and move live gas services before enclosing them. Residents were left without gas for several weeks and faced repair costs of around four thousand pounds. The risks included gas escape, fire, explosion and carbon monoxide poisoning.

What Was The Outcome?

The construction company pleaded guilty to breaches of duties under the Health and Safety at Work etc. Act and was fined £10000 and ordered to pay costs of £4263. The company had previously been served with an Improvement Notice requiring systems for producing written construction phase plans and was found not to have complied. The company director pleaded guilty to separate offences and was fined one thousand pounds and ordered to pay a four hundred pound victim surcharge. The court was told the company and its director no longer work in the construction trade.

Key Points To Consider

Prepare construction phase plans. Ensure a written construction phase plan is produced and available before work starts whenever acting as principal contractor on a domestic project and keep documentary evidence that the plan was issued and followed.

Confirm location and relocation of gas services. Before enclosing or building over existing services, check drawings and site surveys, engage the gas network or a gas safe registered engineer early, and secure written agreements for moving or extending pipework and flues.

Cooperate with regulators and respond to notices. Treat building control and regulator warnings as urgent, keep clear records of actions taken, comply promptly with improvement notices and provide requested information to inspectors to avoid further enforcement.

HSE Prosecution Link

Tags: regulatory, news, construction safety, contractor safety, gas detection, fire safety