Concrete scanning cost in Sydney is driven by how many locations need scanning, how easy they are to reach, whether the slab is post-tensioned and what record you need afterwards. For most coring and cutting work, ground penetrating radar is the method used, because it needs access to one side only and no exclusion…
Concrete scanning cost in Sydney is driven by how many locations need scanning, how easy they are to reach, whether the slab is post-tensioned and what record you need afterwards. For most coring and cutting work, ground penetrating radar is the method used, because it needs access to one side only and no exclusion zone. X-ray still has a place. This guide covers both, and what a quote should include.
What concrete scanning is for
Before a core hole, saw cut or anchor goes into a slab, wall or column, someone needs to know what is inside it. That means reinforcing steel, post-tension tendons, electrical and data conduits, and sometimes heating pipes or voids.
Cutting ordinary reinforcement weakens the element. Cutting a live conduit is an electrical incident. Cutting a stressed post-tension tendon is worse than either: the tendon holds a large load, the slab loses capacity when it is severed, and the repair is specialised and expensive. SafeWork NSW expects embedded services to be identified before concrete is cut or drilled.
What drives concrete scanning cost in Sydney
Scanning is priced on time and difficulty:
- Number of locations. Ten core positions on one floor is one efficient visit. Ten positions across three sites is three.
- Size of each area. A single penetration needs a small grid. A long saw cut or a riser opening needs more.
- Access. Soffits, columns and walls need ladders, scaffold or lifts. Floor scanning is quickest.
- Slab type. Post-tensioned slabs take more care, more passes and more caution in the mark-up.
- Reporting. Marking on the surface is the base service. A written report with scan images and photos is extra work.
- Timing and site rules. After-hours work, inductions and building management conditions in the CBD add time.
A minimum call-out normally applies, so getting every location on a floor scanned in one visit is cheaper than calling back.
How GPR concrete scanning works
A handheld high frequency radar unit is rolled across the surface in a grid. It sends pulses into the concrete and records reflections from anything with different properties, mainly steel and voids. The operator reads the result on screen and marks the surface directly: bar positions, tendon lines, conduits and a clear zone for the core.
GPR is radiation-free. The area stays open, other trades keep working, and results are immediate. It typically images the top few hundred millimetres of a slab, with depth depending on the antenna, the reinforcement density and the concrete itself. This is the method LCG Locating uses for concrete scanning.
How X-ray compares
Concrete X-ray, or radiography, places a radioactive source on one side of the element and a film or digital plate on the other. The image is a true picture of what is inside, and it is easier for a non-specialist to read than a radar trace.
The trade-offs are practical ones:
| GPR | X-ray | |
|---|---|---|
| Access needed | One side | Both sides |
| Exclusion zone | None | Yes, area must be cleared |
| Results | Immediate, marked on site | After the image is processed |
| Works on slab on ground | Yes | No |
| Typical timing | Normal hours | Often after hours |
| Image clarity | Needs interpretation | Clear picture |
Radiography in NSW is regulated, and the operator must hold a radiation licence. The exclusion zone is the reason X-ray on an occupied building usually happens at night.
When X-ray is the better choice
GPR is the default, and it is not always enough. Radar struggles to see past a dense top mat of reinforcement to what lies below it. Closely spaced bars, congested beam and column junctions, and thick elements can all leave the operator uncertain.
In those cases X-ray may give a clearer answer, provided both faces can be reached. A scanner who tells you radar is not adequate for a particular location is doing the job properly.
What a scan cannot tell you
One caveat should be stated plainly. Radar can struggle to tell a conduit from a reinforcing bar, especially a metal conduit lying against the steel, and plastic conduits with no cable in them can be faint. It also cannot confirm whether a conduit is live.
Fresh concrete is another limit. Slabs that are still curing hold moisture that absorbs the signal, so penetration is poor. Slabs on metal decking reflect strongly from the deck. A careful operator marks an uncertain area as uncertain and recommends moving the penetration or checking another way. Confidence everywhere is a warning sign.
Before you book: what to have ready
You will get a faster visit and a firmer price with:
- The proposed core, cut or anchor positions marked on the surface or on a drawing.
- Structural drawings if they exist, especially for post-tensioned slabs.
- Whether the slab is suspended or on ground, and whether the underside is accessible.
- Site access times, induction requirements and the building manager's contact.
- Some flexibility. If a position lands on a tendon, it has to move.
Agree with your structural engineer in advance how far a penetration can be shifted. That decision is theirs, not the scanner's.
Scanning as part of a wider investigation
On refurbishments the question is often bigger than one core hole: what runs under the slab, where the drainage goes, whether there is a void. Concrete scanning sits alongside utility locating for services below the slab and subsurface reporting for voids and buried structures. Having one provider do all three avoids three mobilisations.
Next step
Mark your penetrations, find the structural drawings and check access times with the building. Then request a quote for all locations in one visit.
Common questions
How much does concrete scanning cost in Sydney?
The cost depends on the number of locations, their size, access, slab type and whether a written report is required. A minimum call-out usually applies, so scanning all positions in one visit gives the best value. A firm price needs the address, the number of penetrations and whether the slab is post-tensioned.
Is GPR or X-ray better for concrete scanning?
GPR suits most jobs because it needs one-sided access, has no exclusion zone and gives immediate results. X-ray gives a clearer image in heavily reinforced or congested elements but needs access to both sides and the area cleared. Many projects use GPR first and X-ray only where radar is inconclusive.
Can GPR find post-tension cables?
Yes. Post-tension tendons are a strong radar target and their draped profile, rising over supports and dipping at mid-span, helps distinguish them from flat reinforcement. Drawings and anchor positions at the slab edge are used to confirm. Any location close to a tendon should be moved or referred to the engineer.
How deep can concrete scanning see?
Handheld concrete radar typically images the top few hundred millimetres. The depth achieved depends on antenna frequency, reinforcement density and moisture in the concrete. Thick or heavily reinforced elements may need to be scanned from both faces or checked by another method.
Do I need to clear the area for a GPR scan?
No. GPR emits low-power radio waves, not ionising radiation, so there is no exclusion zone. The scanner needs clear access to the surface, with furniture, floor coverings and stored materials moved off the scan area.