GPR Surveys – what is hidden behind that wall?

What is a GPR Survey?

GPR, or Ground Penetrating Radar, to give it it’s proper title is a non-invasive technology that allows us to scan existing walls to see what is behind them.  GPR Surveys have many different uses but it is particularly valuable for establishing the route of a flue.  Turner Baker have specialist equipment and software to enable us to survey walls and establish in which direction a flue runs behind a fireplace and also if there are any other flues or voids within a wall space.

To get technical, Ground Penetrating Radar is a survey method that uses pulses of electromagnetic radiation to image the subsurface.  It is non-intrusive and non-destructive and is, therefore, a useful surveying technique for the interior of a property.  It can be used to locate a wide variety of metallic and non-metallic materials including:

  • Concrete
  • Metal
  • Plastic
  • Voids

This is extremely useful for renovation projects in older properties.  A disused flue in a room on one floor may be affected by a wall that has been removed in a floor higher up the building.  GPR Surveys can unravel the secrets whilst guiding the planning for any new vision for a property, whether for domestic or commercial use.

All of this can be achieved without making holes or compromising the decoration of the building in any way.  The GPR unit that we use is a handheld device which is pressed against the surface of the wall to get a reading which we can then interpret using the specialist software.

GPR wall surveyThe benefits of GPR surveys are:

  • It is a non-destructive and non-invasive survey which make it safe for use in public spaces
  • GPR detects voids, non-metallic and metallic objects
  • We only need access to one side of the wall or floor to carry out the survey
  • The GPR data that we collect allows us to estimate the depth and dimensions of larger objects or voids
  • Data collection is relatively rapid which allows us to survey large areas

Why is a GPR survey useful?

Ground Penetrating Radar Surveys have proved very useful in renovation projects, particularly for properties that may have been split up into different flats. Walls can incorporate several flues running to fireplaces on different floors of a building.  If, as part of a redesign, you wish to remove a wall, it is important to understand whether that might affect neighbours either above or below.

Additionally, decommissioned flues can be used to accommodate cabling or pipework as it travels through a property – a  GPR survey can facilitate this by establishing where the flues run from and to. Any kind of invasive work – knocking though walls or drilling into walls to accommodate services etc. will benefit from a GPR survey which will show very clearly what is behind a wall.




This is an example of the visual produced by the GPR survey (picture on left) .  Example of GPR survey visualAt Turner Baker, we undertake the analysis of the GPR survey data in house and can provide CAD drawings with all of the relevant information and a full report.  We can also annotate Architects drawings if required.  For more information on GPR surveys please contact us on 01432 839123.