Insights
Why is rebar diameter the hardest (and one of the most important) things to know about your concrete?
11 March 2026
If you manage, renovate, or assess existing concrete structures, you’ve likely encountered missing or inaccurate original drawings about reinforcement. Ground-penetrating radar (GPR) scanning has become the standard solution, fast, non-destructive, and minimally disruptive. However, not all questions about concrete are equally answerable through GPR.
GPR excels at two primary outputs: identifying rebar location and layout with millimetre precision, and measuring concrete cover depth to assess corrosion risk and drilling safety. For many decisions, such as whether cutting is safe, or whether cover meets requirements, these data points suffice.
The challenge lies elsewhere. Rebar diameter is structurally significant, directly determining steel cross-sectional area for load-bearing calculations. Conventional GPR cannot reliably deliver this measurement. Traditional workarounds involved destructive core drilling, time-consuming, and providing only point measurements across potentially vast structures.
Birdsview’s solution employs Full Waveform Inversion (FWI), technology adapted from seismic surveying, analysing complete signal waveforms rather than initial reflections. The system achieves 1–3 mm diameter accuracy without prerequisites such as known spacing or specific concrete conditions, and processes automatically in the field.
How Full Waveform Inversion works
This capability transforms decision-making for building owners avoiding extensive coring, for structural engineers grounding assessments in measured data rather than assumptions, and for contractors knowing exactly what exists before cutting. The Birdsview Concrete scanner delivers results in real time without requiring specialised technical expertise.