We were called to a site near the Leeds Inner Ring Road where a contractor had hit an uncharted gas main. The ground here is a mix of glacial till over Coal Measures sandstone, and old Victorian backfill makes utility records unreliable. That is exactly where a GPR (Ground Penetrating Radar) survey earns its keep. By sending high-frequency radar pulses into the subsurface, we detect metallic and non-metallic utilities, voids, and buried structures without any excavation. In a city with Leeds's density of buried services, a GPR survey before any deep excavation is not optional — it is due diligence. We pair this with a thorough site reconnaissance and often recommend a complementary densidad cono arena to verify compaction of the backfill layers where radar attenuation is high due to clay content.
GPR survey in Leeds detects utilities and voids without digging, even through the city's challenging glacial till and clay-rich backfill.
Scope of work in Leeds
- 400 MHz antenna reaches 3–5 m depth for deep utility mapping and void detection in the glacial till.
- 900 MHz antenna resolves rebar and shallow conduits at 0–1.5 m, critical for city centre pavements and floor slabs.
- Real-time GPS tagging on every trace for CAD export and GIS integration.
- Post-processing with RADAN 7 software to filter out the clay-rich signal noise common in Leeds's subgrade.
Procedure video
Critical ground factors in Leeds
Leeds sits on Carboniferous Coal Measures interbedded with glacial till, and the water table fluctuates heavily with the River Aire's seasonal flow. High clay content in the till attenuates radar signals quickly, reducing effective depth to sometimes under 1 m. That attenuation can miss deeper voids or services if the survey is not set up correctly. We counter this by selecting the lower-frequency antenna and increasing transmitter power — and we always correlate radar readings with a permeabilidad campo test to confirm ground moisture content. Missing a void under a Leeds road slab can lead to catastrophic collapse, so we treat every survey with that risk in mind.
This service complements our laboratory testing work for a complete project analysis.
Our services
We offer two standard GPR survey packages for Leeds projects, each tailored to the city's typical ground conditions and regulatory requirements.
Utility Mapping & Void Detection
Full grid survey over the site area, identifying buried utilities (metal, PVC, clay, fibre), voids, and abandoned structures. Deliverables include CAD plans, GIS shapefiles, and a written report with depth and confidence ratings per target. Typical grid: 1 m x 1 m line spacing for 400 MHz, 0.5 m x 0.5 m for 900 MHz.
Concrete Scanning & Rebar Mapping
High-resolution 900 MHz survey of reinforced concrete slabs, walls, and bridge decks. Locates rebar, post-tension cables, conduits, and voids within the concrete. Used for core drilling safety and structural assessment. Depth penetration up to 0.4 m in dense concrete.
FAQ
How deep can a GPR survey see in Leeds's glacial till?
Depth in glacial till depends heavily on clay content and moisture. With a 400 MHz antenna we typically reach 1.5–2.5 m in dry till, but that drops to 0.5–1 m in saturated clay-rich zones. The 900 MHz antenna is limited to 0–1.2 m in the same ground. We always calibrate on site with a known target depth before starting the full grid.
What is the typical cost of a GPR survey in Leeds?
For a standard utility mapping survey on a 0.5 ha site with reporting, expect a range between £1,010 and £7,000. Smaller concrete scanning jobs (e.g., one floor slab) fall at the lower end; large multi-grid surveys with void analysis sit at the higher end. The exact figure depends on grid density, access conditions, and whether post-processing is needed for clay-rich attenuation.
Can GPR detect plastic water pipes in Leeds city centre?
Yes, but only if the surrounding soil has different dielectric properties. Plastic pipes (PVC, HDPE, PE) are low-contrast targets. In Leeds's clay-rich till, the contrast is often just enough for detection at depths under 2 m with a 400 MHz antenna. We increase confidence by running parallel passes and using hyperbola fitting in post-processing. If the pipe is deeper than 2 m or surrounded by wet clay, detection probability drops significantly.