Frequently asked questions.

Yes. GPR is a widely used non-destructive method for finding and mapping post-tension cables in concrete floors. Skilled interpretation by a qualified surveyor is essential.

Often, yes. Plastic cannot be energised for an electromagnetic locator, which is why GPR is the second method. It struggles in wet clay and made ground.

Yes, GPR can scan through typical floor screed to detect reinforcement and embedded items in the structural slab below. Thick screeds and heating layers may complicate interpretation.

Yes. A Type D desktop search is the first step of every Type B survey we do.

For any drilling into structural concrete where as-built records are incomplete, GPR pre-drill scanning is the standard mitigation. For post-tension floors it is non-negotiable.

Survey-grade terrestrial LiDAR can produce a registered point cloud accurate to a few millimetres, depending on the scanner, range and registration. Mobile and SLAM-based systems are typically centimetre-grade.

GPR depth depends on antenna frequency and material. Concrete scanners are rated by their makers to a few hundred millimetres or more, depending on the instrument; low-frequency ground antennas can reach several metres in favourable ground.

Send the site address, the element to be scanned, the brief, and any drawings to a reputable scanning company. You should hear back promptly, with a quote that states scope, method and deliverable.

Send the location, the element to be scanned, the brief, and any drawings to Corvus. We call back the same working day and follow up with a quote and method.

LiDAR uses laser pulses to measure distance to surfaces. Combined with the known direction of each pulse, it builds a 3D point cloud of the captured space.

GPR data is delivered as on-slab markings on the day, plus a written PDF report and a CAD-ready DXF/DWG plan within 5 working days. The calibration record and surveyor details are included.

A typical pre-drill scan on a small area takes 1–2 hours on site, with marks on the slab before we leave and the written report within 5 working days. Larger reinforcement-mapping or PT scans usually take a full day on site.

A CAT and Genny sweep is a few hours. A Type B is one to three days on site, with the drawing within 5 working days of the visit.

It depends on the area, the survey type and the access. Tell us the site and we call back the same working day with a price.

UK GPR scanning costs vary by scope. A pre-drill scan on a single small area is often quoted as a half-day attendance. Larger or specialist work is priced by site time.

GPR locates targets and gives depth-indicative positions. Accuracy depends on the equipment, the material and the surveyor. Hilti specifies its PS 1000 X-Scan at ±10 mm in plan, with depth to ±10 mm or ±15%; site conditions can reduce this.

We are based in Canary Wharf and on site across the UK every week, including Wales and Scotland. London and the Home Counties carry no travel charge; elsewhere, travel and any overnight are itemised on the quote.

Every surveyor holds a CSCS card. Our utility surveyors hold the ProQual Level 3 Certificate in Utility Mapping and Surveying and deliver surveys to PAS 128:2022. Surveyors working in occupied homes hold DBS checks.

QL-B1 means a service was detected by two methods that agree, with position to ±150 mm and depth to ±15%.

Drilling through rebar damages the bar locally and can reduce the capacity of the structural element. On post-tension elements it can have severe consequences.

Drone surveys are used for site progress capture, photogrammetry, orthomosaic mapping, aerial inspection, and stockpile volumetrics on UK construction sites.

A point cloud is the measurable 3D record of a space or structure. It is used for design, BIM coordination, structural monitoring, drawings, inspection, dispute resolution, and heritage records.

Cover depth is the distance from the surface of a concrete element to the nearest reinforcement bar. It protects the steel from corrosion, fire, and chemical attack.

Rebar mapping is the non-destructive surveying of reinforcement in a concrete element to record bar position, depth, and (where possible) diameter, typically using GPR and ferro scanning.

GPR sees deeper and detects non-metallic items like plastic conduits as well as post-tension tendons; ferro scanning measures cover and estimates bar diameter accurately at shallow depth. They are complementary and often used together.

Most jobs need a records search plus detection, which gives QL-B1 to QL-B4 on the drawing. Specify the survey type and methodology, and the drawing shows the quality level achieved.