Private chimney flue survey, South Kensington

For hundreds of years, open fires heated London’s buildings. This changed in the 1950s with the introduction of the Clean Air Act, but the legacy of the fireplaces and chimney flues continues to affect development today.

Typically, 18th century townhouses had a fireplace in every room, each with a flue built in to the masonry walls. Flues leading to the chimneystack on the roof are not straight; they bend to control the draw of the fire and to allow space for other flues. Because of this, a four-storey property with a basement can contain twenty flues by the time it reaches roof level in just one party wall.

Private flue surveyTechnics was commissioned to survey the location of chimney flues in several walls, at fourth floor and roof level, during the design phase of a project to develop a penthouse in South Kensington, London.

The client’s design proposed inserting structural steel beams into the walls. Following a detailed chimney flue survey using a high frequency Ground Penetrating Radar antenna to scan across wall surfaces, Technics enabled the owner to review the findings and make the decision to proceed with the project.

The client explained: “We instructed Technics to undertake a GPR scanning survey of the party walls within a four storey Victorian terrace property that had previously been laterally converted. We needed to ascertain which chimney flues were still in use and which were lined.

“Technics were very knowledgeable and helpful, organising for the survey to be undertaken within our timeframes and a report produced according to our requirements. They were very competent, professional and efficient and the information provided following the survey was invaluable, meaning the structural designs could be confirmed, which meant reducing some of the project risk and maintaining project programme.”


For a successful survey, good access is required to the full height of at least one elevation of the wall containing flues. The GPR equipment used saves survey data for off-site processing and interpretation. Once this is complete, a CAD drawing is produced showing the flues.

If you require any further information on Ground Penetrating Radar for your project, please call one of our office locations or email


Chimney flues survey