Guidance on constructing or modifying a chimney flue

Current Building Regulations in England and Wales (2000) lay down goal setting requirements for the construction of chimneys and flues and are supported by Approved Document J (2002) which provides guidance on meeting the requirements. This, in turn, is supported by a raft of British Standards and other recognised industry documents which have been developed during a period of several decades to lead and reflect good industry practice as applied in England and Wales.

Repair of flues

Flues are controlled services as defined in Regulation 2 of the Building Regulations, that is to say they are services in relation to which Part J of Schedule 1 imposes requirements. If renovation, refurbishment or repair amounts to or involves the provision of a new or replacement flue liner, it is “building work” within the meaning of Regulation 3 of the Building Regulations. “Building work” and must not be undertaken without prior notification to the local authority. Examples of work that would need to be notified include:-

• relining work comprising the creation of new flue walls by the insertion of new linings such as rigid or flexible prefabricated components.
• a cast in situ liner that significantly alters the flue’s internal dimensions.

Anyone in doubt about whether or not any renovation, refurbishment or repair work involving a flue is notifiable “Building work”, could consult the building control department of their local authority, or an approved inspector.

Where it is proposed to bring a flue in an existing chimney back into use or to re-use a flue with a different type or rating of appliance, the flue and the chimney should be checked and, if necessary, altered to ensure that they satisfy the requirements for the proposed use.

The chimney and fuel industry, together with the DLTR have produced a guidance document to help the UK industry make the gradual change from using British Standards to using the new European Standards.

Guidance is provided on checking the condition of both newly completed flues and flues that are to be brought back into service or used for a different type of appliance. This has enabled removal of the 1st Feb 1966 cut-off date for chimneys built under former control. For existing chimneys found to be unsatisfactory, suitable relining systems for all fuel types are described.

Guidance is given on minimum flue height and a limit is introduced on the number of bends that can be made. The maximum bend angle for a flue serving a solid fuel appliance is increased from 30º to 45º.

The guidance on building masonry chimneys, which includes flue block chimney for gas appliances, has been enhanced and clarified with more information on construction techniques.

New guidance is given on the distancing of low-level flue outlets from property boundaries that complement recent changes in the Gas Safety (Installation and Use) Regulations.

The guidance on avoiding unacceptable interaction between combustion installations and extract fans has been extended.

New diagrams and examples have been incorporated by way of practical explanation.

Please refer to:-

BFCMA - British Flue & Chimney Manufacturers Association

A guide to choosing and using flues and chimneys for domestic gas burning appliances - the BLUE guide.

Choosing and using flues and chimneys for domestic solid fuel and wood burning appliances - the YELLOW guide.

Combustion appliances and fuel storage systems

See also

• Flats - conversion and new build