What Is As-Built Documentation? A Complete Guide

Q: How accurate is as-built documentation?

When produced from 3D laser scanning, as-built documentation typically achieves accuracy in the range of about 2 to 20 mm, depending on site conditions, scope, and the deliverable. That is far tighter than hand measurements can reliably achieve across an entire building.

Q: Do you need access to the entire building?

Ideally, yes, for complete documentation, but scanning is flexible. Capture can be scheduled around occupants and operations, scoped to specific floors or areas, and performed without contact with finished surfaces, which is important for occupied and heritage buildings.

Q: Which deliverable should I request?

It depends on your use. Choose a registered point cloud for raw measurable data, a BIM model for design and coordination, CAD drawings or 2D floor plans for documentation and permits, a SketchUp model for visualization, or a 360 walkthrough for remote review. Many projects combine several.

As-built documentation is an accurate, measured record of a building exactly as it has actually been constructed, rather than how it was originally designed. It captures the real dimensions, layout, and conditions of a structure, most often using 3D laser scanning, and is delivered as registered point clouds, BIM models, CAD drawings, or 2D floor plans.

What is as-built documentation?

Every building starts as a set of design drawings. But buildings rarely get built exactly as drawn, and they keep changing long after construction ends. Walls move during construction, mechanical systems get rerouted, tenants renovate, and decades of modifications pile up. The original drawings, if they still exist, slowly drift away from reality.

As-built documentation closes that gap. It is a current, verified record of the building as it physically exists today: actual wall locations, floor-to-floor heights, structural elements, and the position of doors, windows, and building systems. Where "as-designed" drawings show intent, as-builts show reality, which is exactly what you need before you renovate, lease, coordinate trades, or plan a restoration.

What as-built documentation includes

"As-built documentation" is an umbrella term. Depending on what your project needs, it can be delivered in several formats, often more than one from the same capture:

Registered point clouds - millions of precisely measured 3D points that form a complete, measurable digital twin of the existing conditions.
As-built BIM models (Revit) - intelligent 3D models with walls, floors, doors, windows, and MEP systems modelled to your required Level of Detail.
As-built CAD drawings (AutoCAD) - traditional 2D plans, sections, and elevations extracted from the scan data.
2D floor plans and elevations - clean, dimensioned drawings for space planning, leasing, permits, or renovation design.
3D models (SketchUp) - lightweight models for design exploration, rendering, and stakeholder presentations.
360 walkthroughs - interactive visual records for remote review and archival of existing conditions.

How as-built documentation is produced

Modern as-built documentation is built on 3D laser scanning. The workflow is straightforward:

Capture. A terrestrial laser scanner records the building from many positions, measuring millions of points per scan. Capture is non-contact and can be scheduled around occupants.
Registration. The individual scans are aligned into a single, unified point cloud in one coordinate system, then verified against control measurements.
Modelling and drafting. The point cloud becomes the source of truth for producing the deliverables you requested, whether that is a Revit model, AutoCAD drawings, floor plans, or all three.
Quality review. Every deliverable is checked against the source scan data, dimensions are spot-checked, and any assumptions are documented before release.
Delivery. You receive production-ready files in your preferred formats, on schedule.

For a real example of this process on a sensitive site, see our heritage building laser scanning case study.

Why accuracy matters

The whole value of as-built documentation rests on one thing: trust in the numbers. Hand measurements with a tape are slow, easy to get wrong, and almost impossible to verify after the fact. Small errors compound across a floor plan, and a single bad dimension discovered during construction can mean costly rework or change orders.

Laser-scanned as-builts typically achieve accuracy in the range of about 2 to 20 mm, depending on site conditions, scope, and the deliverable. Because the point cloud is a permanent, queryable record, you can also return to it later to pull a dimension you did not know you needed, without a second site visit. Accuracy targets are always confirmed during scoping.

Who needs as-built documentation

As-built documentation supports a building across its entire lifecycle. The most common clients are:

Architects and interior designers who need reliable existing conditions before design development.
Developers and property owners performing due diligence, leasing, or planning capital projects.
Renovation and construction contractors who need accurate existing conditions to plan and price work.
Retail chains and facility managers documenting tenant improvements, leases, and portfolios.
Structural, mechanical, and electrical engineers assessing buildings and coordinating systems.
Heritage and institutional teams documenting protected structures for preservation and restoration.

File formats you receive

As-built deliverables come in standard, industry-recognized formats so they drop straight into your existing software:

Point clouds: .RCP, .E57, .PTX, .PTS, .LAS
BIM models: .RVT (Revit)
CAD drawings and plans: .DWG, .PDF
3D models: .SKP (SketchUp)

Not sure which format fits your project? That is exactly what scoping is for, and you can review the full breakdown on our services and deliverables page.

Frequently asked questions

How is as-built documentation different from as-designed drawings?

As-designed drawings show how a building was intended to be built. As-built documentation records how it was actually constructed, including the changes and deviations that happened during construction and over the building's life. As-builts reflect reality; as-designed drawings reflect intent.

How accurate is as-built documentation?

When produced from 3D laser scanning, accuracy is typically in the range of about 2 to 20 mm, depending on site conditions, scope, and the deliverable. That is far tighter than hand measurements can reliably achieve across an entire building.

How long does as-built documentation take?

On-site scanning of a typical commercial building takes hours to a few days depending on size and complexity. Processing and modelling into BIM, CAD, or floor plans usually takes one to several weeks. A clear scope and timeline are confirmed before the project begins.

Do you need access to the entire building?

Ideally yes, for complete documentation, but scanning is flexible. Capture can be scheduled around occupants, scoped to specific floors or areas, and performed without contact with finished surfaces, which matters for occupied and heritage buildings.

Which deliverable should I request?

It depends on your use: a registered point cloud for raw measurable data, a BIM model for design and coordination, CAD drawings or floor plans for documentation and permits, a SketchUp model for visualization, or a 360 walkthrough for remote review. Many projects combine several.