Post-Construction BIM Verification

Drone As-Built Surveys.

Compare what's actually on site against the design model. Our drone-and-scan drone operators capture a measurable point cloud of the finished build and overlay it against your BIM — exposing every deviation before it becomes a snagging dispute.

“Every drone pilot on this network is personally vetted by me — insurance, qualifications, flight history.”

Peter Leslie · Founder & GVC Drone Pilot

Trusted by site managers & agencies across the UK

Finished the build?

Post your as-built details to compare quotes from BIM-capable specialists.

"Built to design" is rarely built to design.

Between design intent and handover, every project accumulates silent deviations. An as-built drone survey surfaces them before you sign off and pay retention.

Hidden Deviations at Handover

Beams shifted by 40mm, slab levels off by 25mm, MEP runs dropped through the wrong chase. By the time your FM team notices, the retention is paid and the subbie is on another job.

Disputed Final-Account Claims

Retention disputes revolve around what was actually built versus what was specified. A dated as-built point cloud is a legally robust record that cuts these conversations short.

FM Inheriting Wrong Drawings

A facilities team working from design drawings that don't match reality will drill into the wrong places, order the wrong parts, and lose hours every week. A Scan-to-BIM as-built fixes that for the life of the asset.

An as-built is only useful if you can actually compare it to the design.

By Peter Leslie, Founder & GVC Drone Pilot

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Lots of drone pilots will sell you a point cloud. Far fewer will hand you a deviation report that you can take to a QS and settle a final-account dispute with.

The drone operators I match to as-built work run their scans and drone flights through tools like Autodesk ReCap, Navisworks, or Leica Cyclone — registering the finished-build point cloud directly against the federated BIM model and exporting a coloured deviation report.

You don't just see what's there. You see exactly where reality has parted company with the design.

BIM-Literate Drone operators

Scan-to-BIM & Clash Detection

Reality vs design, laid out for your QS and FM team.

Three deliverables that travel from site hut to boardroom.

Point Cloud vs CAD Overlay

The registered as-built point cloud overlaid against the federated BIM or CAD model in Navisworks or BIMcollab. Orbit, section, and measure the real vs intended geometry side by side.

Deviation Report

A colour-coded heat map and tabulated list of every deviation above a user-set tolerance (typically ±10mm, ±25mm, ±50mm). The single document that turns a dispute into a closed-out item.

Scan-to-BIM Model

Optional Scan-to-BIM deliverable at LOD 200 or 300 — an updated Revit model reflecting the asset as it actually stands. The version your FM team should be running for the next 30 years.

From final fix to deviation report in 3 steps.

Scoped around handover, not fitted in between other jobs.

Share the BIM

Upload your federated model and nominate the tolerances you care about (structural, MEP, finishes). We brief the right scan-plus-drone operator.

Capture the As-Built

The drone operator flies the exterior and scans the interior in a single coordinated visit, registering both datasets against shared control.

Compare & Report

Registered cloud is compared to the BIM. You receive the overlay, the deviation report, and — if requested — an updated Scan-to-BIM model.

Start Your Project Brief

Handovers with nothing hidden.

Main contractors, client-side QSs, and FM managers using drone as-builts on UK projects.

"The deviation report caught a steel frame that was out by 32mm at third-floor slab level. Sub raised it before retention release and we got it right first time. That one finding paid for the survey ten times over."

Tom J.

Senior QS, Birmingham

"Our FM team now works from the Scan-to-BIM model for planned maintenance. Every service run, duct, and fixing is where the drawings say it is — because the drawings are now the scan."

Vivek N.

FM Director, Reading

"Navisworks clash detection on the registered cloud found three service conflicts nobody had picked up in 18 months on site. Proper grown-up BIM validation, not marketing."

Elin D.

BIM Manager, Cardiff

As-Built Survey FAQ

Scan-to-BIM, clash detection, and how as-builts fit into your close-out process.

What is Scan-to-BIM and do I actually need it?

Scan-to-BIM is the process of building a Revit model directly from a registered point cloud, so the model reflects the as-built reality rather than the original design intent. It is essential if your FM team will run the asset from BIM, or if you're planning an extension, refurbishment, or decommissioning exercise against the existing structure.

Can you do clash detection between the as-built and the design model?

Yes. Drone operators run the registered point cloud against the federated BIM in Navisworks or BIMcollab with user-set tolerances. The output is a clash report identifying real conflicts between what was built and what was drawn — often the fastest way to catch MEP or structural deviations before handover.

When in the programme should we book the as-built?

Best practice is immediately after final fix but before any ceilings, risers, or service chases are closed up — that way the scan captures first-fix services still visible. A second fly-and-scan at practical completion then records the finished state for the O&M manual.

What deliverable format will my QS or FM team actually use?

QSs use the PDF deviation report and the Navisworks overlay to run meetings. FM teams use the Revit (RVT) Scan-to-BIM model and the raw E57 point cloud for ongoing CAFM workflows. We deliver all three as standard on larger projects so nobody is locked into a single tool.