Locating embedded metal in masonry

Corrosion of embedded metal can cause damage to ornate mouldings

GPR offers an excellent NDT method of detecting embedded metal in masonry, particularly for heritage structures, where metal is often used to form a structural frame, strengthening and fixing of masonry blocks.

Why locate embedded metal?

Embedded metal has been used for strengthening masonry structures for hundreds of years. Most commonly the embedded metal includes:

  • Structural I beams and columns
  • Metal dowels
  • Pins and cramps

With time, problems can occur with metal deterioration, notably corrosion. Repair and preventative maintenance works are often required. It is therefore necessary to understand how the structure was built and to locate and identify all embedded metal.

GPR radargram showing steel I beam detected in masonry wall

GPR radargram showing steel I beam detected in masonry wall 

Site Survey

Sandberg embedded metal location  investigation surveys typically use a combination of metal detection and Ground Penetrating Radar (GPR) scanning techniques. Metal detection offers a quick method to identify areas of metal. It should be noted that most metal detectors are electromagnetic and will only detect ferrous metals; they will not detect stainless steel or brass. GPR will detect all metals and also provide information about the depth and information about section and approximate size may also be possible. GPR can also help determine construction detail, thickness of construction and detect other features such as voids.

Using GPR to locate embedded metal in masonry

Scanning with GPR to locate embedded metal in masonry

The GPR survey can either utilise single scan lines collected as required (e.g. along mortar beds), or on a regular orthogonal grid to provide coverage of a nominated area. Position of scan lines and distances are recorded relative to suitable fixed reference points. This enables accurate positioning of detected embedded objects. The data is saved electronically for off-site processing, analysis and interpretation.


Results are presented in a comprehensive report. The position of all detected embedded metal, other features and anomalies is typically marked on suitable CAD drawing. Reports are issued in pdf format; where applicable, original CAD drawings are also issued in AutoCAD .dwg format.

Need more information

Contact us

Contact us to find out more about our GPR surveys to Locate Embedded Metal in Masonry and how we can help you:

Telephone: 0207 565 7056

Information sheet

Download our information sheet about GPR surveys to detect embedded metal in masonry.