Post-tension scanning before coring. The one strike you can't undo.

The tendon releases its stored force — 15–20 tonnes — explosively and instantly. The strand can whip, the anchor can blow out, the surrounding concrete spalls, and the slab loses the compression it relies on to span. It's a genuine safety event (injuries happen), the job halts, and the repair — re-anchoring or external post-tensioning under structural engineering — runs $20,000–$75,000+ and weeks of delay on a floor that's now structurally suspect. Unlike rebar or conduit, there's no recovering a cut tendon; prevention is the only option.

No — and this is the single most dangerous assumption in concrete coring. Drawings are frequently missing, show design intent rather than as-placed reality, or are simply wrong: tendons get shifted in the field during installation, drape varies, and revisions don't always make the as-builts. A 'plan' tendon is not a located tendon. Engineers across BC condition coring permits on a physical GPR scan precisely because drawings can't be trusted to keep a core bit off a live tendon. Drawings inform the scan; they never replace it.

The 1.6 GHz concrete antenna sends a radar pulse that reflects off the tendon and its sheath or duct, which contrast sharply with the surrounding concrete. The operator runs a two-axis grid to trace the tendon's draped path across the area and separate it from rebar and conduit, then marks keep-clear zones. Lateral accuracy is excellent — a couple of centimetres, more than enough to shift a core clear — and the radar is read against the slab's age and construction to interpret the drape correctly.

Lateral position (where the tendon sits on the surface) is the accuracy that matters for keeping a core clear, and it's excellent — typically within a couple of centimetres on a competent scan. Depth to the tendon is a calibrated estimate (within ~10–15%), useful for planning but secondary, since the goal is to not be over the tendon at all rather than to drill to a precise depth beside it. We mark conservative keep-clear zones around the located path.

Most multi-storey concrete construction since the early 1970s: high-rise residential and office towers, podium slabs, and the parkade decks beneath them, plus many transfer slabs and elevated structural floors. If you're coring an elevated slab in a Metro Vancouver (or any BC) tower or parkade built in the last fifty years, assume post-tensioning until a scan proves otherwise. Slab-on-grade and older low-rise are less likely but still worth confirming.

No — locating tendons is part of a competent concrete scan, performed with the same GPR equipment and crew that identify rebar and conduit in the same pass. There's no PT surcharge. What affects the price is scope: number of core locations, slab congestion, and whether the engineer requires a formal report. A post-tensioned slab simply makes scanning non-negotiable; it doesn't make it pricier. Typical single visits run $300–$1,500.

Yes — and it's critical. Cutting a large opening (for a stair, elevator, or shaft) in a post-tensioned slab means severing tendons deliberately, which requires the structural engineer to design controlled de-tensioning and re-anchoring. Our scan maps every tendon crossing the proposed opening so the engineer designs from located reality, not drawings — turning a potentially catastrophic saw cut into a planned structural operation.

We deliver the clearance standard — a physical GPR scan that locates the actual tendons at the actual penetration with conservative keep-clear marking and, where required, engineer documentation — which reduces the risk as far as the technology allows. No honest scanner claims a zero-risk absolute (radar has limits in extreme congestion or depth, and we'll flag and recommend alternative methods where a slab is beyond GPR's envelope). What we guarantee is that you're coring on located reality, with stated confidence, instead of on a drawing and a prayer.