How GPR Can Help You with Preconstruction Plans

4 January 2023
 Categories: Construction & Contractors, Blog


When you plan to build some structures on a piece of land that may be surrounded by other developed areas, you need to be particularly careful. After all, there is a strong likelihood that you may find some underground utilities below ground that service those other developments and that may have been in place for some time. Often, you can get in touch with utility companies for information, but not always, so what do you do in this latter case?

Expect the Unexpected

When you do not have accurate information about underground obstacles, you must always assume that there is something in place. And to find out exactly what you're dealing with, you should bring in specialist contractors who will have ground-penetrating radar (GPR) equipment.

GPR in Action

GPR works by sending microwave energy bands down into the soil from a transmitter. This electromagnetic energy will "bounce" off anything solid below ground, causing a distinct echo that the onboard antenna will receive. As the electric magnetic impulse hits the object (such as a utility conduit), the signal will be reflected, refracted or scattered based on the density of the object in question. The receiver will be able to interpret those signals due to be highly sophisticated software and can translate them into images on the screen. So the technician can clearly see exactly what is below ground (if anything). The GPR device will also tell you the composition of the ground material and whether you will find any particularly solid rock when you commence your build.

Detect Different Materials

GPR is an excellent tool in this situation and is able to detect underground obstacles made from a variety of different materials. For example, it can detect concrete, PVC, metal, plastic and natural materials, so it will easily show any underground utility lines or pipes. If there are any major rock obstructions or other geological features, you will quickly find out and reveal the presence of groundwater tables.

Minimise Disturbance

Perhaps most importantly of all, you will not need to disturb the ground to use GPR. This means that you don't have to dig or excavate with associated risk and will not need to damage any landscaping that may already be in place.

Understand the Limitations

The GPR machine does not have an endless capability and can only penetrate the ground to a certain depth. The actual depth will depend on the nature of the soil or rock in question, but it should certainly be sufficient to identify utility works, which tend to be relatively close to the surface.

If you have any other questions, get in touch with your contractor for their advice. For more information on ground-penetrating radar, contact a professional near you.