Older buildings need repair and restoration. This is often carried out as an ongoing maintenance programme. If the building is in a state of decay, a major restoration project may be necessary to restore it to its former glory. How can GPR help?

Several factors influence the restoration type. These may include whether the building is private or public, a listed or historic building, and the finance available.

Notre Dame, Paris

There is, however, another scenario, highlighted by the disastrous fire of Notre Dame in Paris. The cathedral is part of a UNESCO world heritage site covering the banks of the River Seine in Paris. The cathedral lost its gothic spire, roof and precious artefacts in a major fire on 15 April 2019. In this case, the disaster was caused by fire, but similar scenarios could be caused by earthquake, war or terrorism.

Assessing the damage

Following a major disaster, the structural integrity and stability of the building can be in doubt. Concrete can lose up to almost 90% of its strength. Furthermore, limestone loses up to approximately 75% of its strength on exposure to heat over 600C. Following the fire of Notre Dame, the stability of the cathedral’s stone vaults is unknown. The temperature shock caused by the heat of the blaze, followed by the cold water used by firefighters, may have weakened the stone. Laboratory testing can confirm if this is the case.

As part of the assessment, it may be necessary to verify the construction details. Alternatively, if they are unknown, determine them. Other issues, such as corrosion, movement, cracking, spalling, and degradation of materials, may need investigation.

How can GPR help?

So, how can Ground Penetrating Radar (GPR) help? For older buildings, there are unlikely to be any as-built drawings, so, the construction detail is likely to be unknown. An intrusive investigation may not be an option for historic or listed buildings. Ideally, any methods used should be non-destructive.

Ground Penetrating Radar is a non-intrusive survey technique that detects sub-surface changes. Sandberg has developed many specialised GPR techniques, which can help in building restoration projects. We also have considerable expertise in the use of GPR in the Construction Industry:

Our experienced GPR Manager and Surveyors work closely with our clients to ensure we provide the required information.

The Houses of Parliament in London
The Houses of Parliament in London, a classic example of gothic architecture. GPR is an NDT method and can be useful in determining construction detail, thickness, location of voids and cavities and more.

Further information

For more information about the GPR surveys we offer, see Ground Penetrating Radar Surveys.

We would love to hear from you. For further information, please contact us to discuss your requirements and find out more about how GPR could help you. If required, we will happily provide a no-obligation quotation.