Utility surveys
Locating and mapping buried services across a site or a road before excavation starts. Worth doing before any dig, from a single gate post foundation to a full car park.
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GPR Surveys and Utility Detection in London
Ground penetrating radar surveys that show what is buried under a site before a machine goes anywhere near it, across London and the counties around it.
How a GPR Survey Finds Buried Services
Ground penetrating radar sends short pulses of radio energy into the ground and listens for what bounces back. Every time the material changes, at a pipe wall, a cable, a rebar mat or a void, part of that pulse reflects. Reading the reflections shows where something is buried and roughly how deep, with nothing dug and nothing broken.
The case for it is blunt. Striking a live cable can burn or kill the person on the tool, and a gas main clears the street. Even a water main, which nobody treats as dangerous, means a lost day, a claim from the utility and a very awkward conversation with the client. A survey costs a small fraction of any of that.
Radar alone is not enough, and neither is an electromagnetic locator. EM finds live cables and anything carrying a traceable signal but is blind to a clay drain or an empty duct, while radar reads shape rather than signal. We run both, mark what we find on the ground in paint for the gang, and follow it with a drawing showing routes against fixed site features and depth of cover where it could be read.
Concrete gets scanned for a different reason. Before anyone cores a slab for a bollard pit, a drain or a fixing, we look for the reinforcement, any tendons, the conduits and voids underneath. Cutting a tendon in a post tensioned slab is a structural problem rather than an inconvenience, and it is not something that can be patched afterwards.
Radar does not see everything, and anyone telling you otherwise is selling. Wet ground and heavy clay soak up the signal, so depth drops with the conditions and with the antenna in use. Plastic pipe with no tracer wire is genuinely hard to find. A survey shrinks the risk a long way, it does not remove it. Safe digging practice still applies, and since our own gangs do the digging, we work that way ourselves.
What that includes
- Utility detection and mapping before excavation
- GPR and electromagnetic locating run together
- Services marked out on the ground in paint
- A drawing of what was found
- Depth of cover recorded where readable
- Concrete slab scanning before coring or cutting
- Reinforcement, tendons and voids located in slabs
- Survey level agreed with you for the job
Types of GPR Survey
Concrete scanning
Scanning a slab, a wall or a deck before anyone cores, cuts or drills it. Finds reinforcement, tendons, conduit and voids, so the hole goes where it will not do damage.
Site surveys
A wider sweep of a whole site ahead of construction, picking up services, old foundations, backfilled trenches and voids. Useful when the record drawings are thin or the ground has been built on before.
On site
How a GPR Survey Runs
The same five stages every time, with the programme written down before anybody starts digging.
Book a site visit- Stage one
Site visit and survey
We come out and look at the ground, the power, the drainage, the traffic and the risk, and take measurements on site instead of guessing from a photograph.
- Stage two
Design and written quote
A drawing and an itemised quotation naming the exact equipment, so you can compare it like for like with anyone else you have asked.
- Stage three
Civils and groundworks
Excavation, drainage, ducting and foundations, carried out by our own team to the programme we agreed.
- Stage four
Installation and commissioning
Fit, wire, set the force limits, prove the safety devices and test the whole system before anybody signs it off.
- Stage five
Handover and aftercare
The paperwork, and a walkthrough for whoever uses it every day.
Common questions
Questions About GPR Surveys
What is ground penetrating radar in plain terms
It is an antenna pushed or wheeled over the ground that fires radar pulses downward and records the echoes. Buried objects and voids reflect part of the pulse because they are a different material to the soil around them. The result is a picture of what is under the surface, built without digging.
Will the survey find absolutely everything
No, and it would be dishonest to say otherwise. Wet or clay ground cuts how deep the radar reaches. Plastic pipe laid without a tracer wire gives almost nothing back. What a survey does is turn an unknown into a much smaller unknown, which is why safe digging practice on the day is still part of the job.
Do I get a drawing or just marks on the floor
Both. Marks on the ground are what the gang works to, and they last until the next rain or the next sweeper. The drawing is the record, showing routes tied to features that will still be there in a year, with depths noted where the ground let us read them.
What level of survey do I need
That depends on what you are doing and what the risk is. Scanning one slab before a core hole is a different job to mapping a whole site before construction. We agree the scope and the level with you for the job in front of us.
Can you do the survey and then the digging
Yes, and that is usually how it works here. Groundworks are our own trade, so the people reading the radar are the people whose machine goes in afterwards. Nobody is handing a drawing to a stranger and hoping they read it the same way.
Related Services
Utilities and groundworks
Excavation, drainage, service trenches and ducting, dug by our own team and put back so the ground above stays sound long after we have gone.
Read moreLeak detection
Finding a water leak without opening up the whole site, then repairing it and putting the surface back the way it was.
Read moreExcavation and digger work
Machine work as a service in its own right, from a site strip or a trench to breaking out concrete, with the operator included.
Read more
Tell us about the site and we will tell you what it needs
Send a photograph and a postcode and we will come back to you with what the site needs.