Ferro Scanning vs GPR: Which Do You Need?

Before any drilling, coring or cutting into concrete, you need to know what’s inside the slab or wall. Two specialist survey methods make this possible: ferro scanning and ground penetrating radar (GPR) scanning. Both are non-destructive and both are used by BritCut operatives on sites across the UK — but they work differently, detect different things, and suit different situations. This guide explains the difference so you can specify the right method for your project.

What Is Ferro Scanning?

Ferro scanning uses electromagnetic pulse induction technology to detect ferrous (iron-based) metallic objects within concrete. It is specifically designed to locate steel reinforcement bars (rebar) and produces highly accurate data on rebar position, concrete cover depth, bar diameter, and bar spacing.

BritCut uses Hilti PS 300 Ferroscan and PS 1000 X-Scan equipment. These systems offer two scanning modes: Quickscan, which marks rebar positions in real time on the concrete surface, and Imagescan, which captures detailed 2D and 3D maps of the reinforcement network for structural assessments and formal reports.

What ferro scanning is best at:

• Precise rebar position mapping
• Concrete cover depth measurement (accurate to ±3mm)
• Bar diameter estimation
• Bar spacing analysis
• Quick pre-drilling rebar avoidance on site
• Quality control checks on new builds

What Is GPR Concrete Scanning?

Ground penetrating radar (GPR) uses electromagnetic pulses that penetrate concrete and reflect back when they hit objects with different electrical properties. The key difference from ferro scanning is that GPR detects both metallic and non-metallic objects — it does not care whether something is ferrous or not.

BritCut uses the Proceq GP8000 for GPR surveys. This system detects rebar, post-tension cables, plastic pipes, conduits, voids, and changes in slab thickness — all in a single scan pass.

What GPR scanning is best at:

• Locating post-tension cables (critical before any coring)
• Detecting plastic pipes and non-metallic conduits
• Identifying voids and delamination within concrete
• Mapping utilities embedded in slabs
• Measuring slab thickness
• Complex structural investigations where multiple object types are present

The Key Differences at a Glance

When to Use Ferro Scanning

Ferro scanning is the right choice when your primary concern is rebar. For pre-drilling and pre-coring surveys where you need to know exactly where the bars are and where the safe zones are, ferro scanning gives you faster, more precise reinforcement data than GPR. It is also the preferred method for:

• Rebar avoidance before diamond drilling or core drilling — Quickscan mode marks safe drill positions directly on the slab in minutes
• Structural assessments and refurbishment projects — where original drawings are unavailable and you need to verify the reinforcement layout
• Quality control on new builds — confirming rebar has been placed to specification before a pour is accepted
• Cover depth surveys — where corrosion risk or structural adequacy needs to be assessed

When to Use GPR Scanning

GPR is the right choice — and often the only safe choice — when the concrete may contain post-tension cables, plastic services, or when you need a broader picture of what’s embedded in the structure. Specifically:

• Post-tensioned slabs — always — Cutting or coring into a post-tension cable can cause immediate structural failure. GPR is mandatory before any work on PT slabs.
• Service-heavy slabs — Where M&E conduits, drainage pipes or heating circuits are embedded, GPR reveals both metallic and plastic services.
• Voids and delamination — If structural integrity is in question, GPR can identify internal voids before they become a safety issue.
• Infrastructure and civil engineering — Bridge decks, tunnels, and highway structures where comprehensive condition surveys are needed.

Can You Use Both Together?

Yes — and for complex projects, using both is often the right approach. A combined ferro scan and GPR survey gives you the most complete picture: precise rebar mapping from the ferro scan, and detection of non-metallic services, post-tension cables and voids from GPR. BritCut operatives carry both systems and can carry out combined surveys in a single site visit, producing a comprehensive pre-works report that covers all embedded features.

Summary: Ferro Scanning vs GPR

If you need precise rebar data quickly, ferro scanning is faster and more accurate for reinforcement-specific surveys. If you’re working on a post-tensioned structure, or need to detect plastic pipes, conduits or voids, GPR is essential. When in doubt — or on any complex project — use both.

BritCut provides both ferro scanning and GPR concrete scanning services across the UK, with same-day attendance available for urgent pre-works surveys. Call us on 01322 221533 or request a free site survey to discuss your requirements.