Measured Building Surveys
Precise, laser-scanned as-built drawings — floor plans, elevations, sections, 3D and BIM models an architect can design from directly. Accurate to millimetres, across London, Surrey and Sussex.
What is a measured building survey?
A measured building survey is a precise, scaled record of a building exactly as it stands — captured on site and delivered as CAD drawings or a 3D/BIM model your design team can work from directly. It is the reliable baseline for any renovation, extension or development: the real building, not the idealised one on old plans.
Planning authorities require ‘existing’ and ‘proposed’ drawings that align perfectly, and inaccurate existing drawings are one of the leading causes of application delays. A proper measured survey removes that risk at the outset. It’s a different thing from a condition (Level 3) survey — that tells you what’s wrong with a building; a measured survey tells you its exact geometry. For the full walk-through, see our step-by-step guide to measured building surveys.
What you get
Every survey is tailored to your project and level of detail (LOD). Typical deliverables include:
2D CAD drawings
Floor plans, elevations, sections and roof plans in DWG/DXF — the industry standard for AutoCAD.
Point cloud data
The raw laser-scan dataset in your preferred format (.e57, .rcp, .las, .pts and more) for use in any CAD or BIM package.
3D & BIM models
A full 3D model or Revit/BIM model for projects that need it — scan-to-BIM to your required LOD.
Georeferenced data
Tied to real-world OS coordinates and height above mean sea level (AMSL) where required.
Photographic records
A visual record of the building to support the drawings and capture detail.
Topographical add-on
We can capture a topographical survey of the surrounding site on the same visit, with fixed control points.
How it works
The scanning phase. We use a terrestrial laser scanner (TLS) that emits a laser beam up to around 80m. When the beam hits a surface it bounces back to the receiver; because the speed of light is known, the distance is calculated from the time of flight. The scanner rotates and fires up to hundreds of thousands of points per second, and we reposition it around the building.
Each position is ‘registered’ to the others, building millions of points into a single geomatic point cloud — a precise 3D digital twin of the building.
The drawing phase. Back in the office, our CAD technicians slice and trace the point cloud to produce accurate 2D drawings, and a 3D or BIM model where required. Because everything derives from a single accurate dataset, the outputs are consistent and dimensionally reliable — not sketched approximations.
Accuracy & standards
Because the drawings are traced from laser-scan data, we typically achieve room accuracy of 1–3mm — a significant improvement on traditional hand measurement. Final drawing accuracy is comfortably within the ±5mm the industry works to.
We work to the RICS professional standard ‘Measured Surveys of Land, Buildings and Utilities’ (3rd edition) and the TSA Client Guide to Measured Building Surveys, which set out survey categories and accuracy bands. As RICS-regulated surveyors we comply with that guidance as a minimum — and in practice our data is more accurate again. Where floor areas are needed to a defined basis, we also measure to IPMS and the RICS Code of Measuring Practice (see our IPMS area assessment service).
What we survey — and who it’s for
Residential
Houses and flats for extensions, loft and basement conversions and reconfiguration.
Commercial
Offices, retail and industrial units for fit-out, refurbishment, lettings and asset management.
Heritage & listed
Complex and historic buildings — one of our most challenging jobs was a Grade II* windmill in Sussex.
Education & public
Schools, institutional and public buildings requiring accurate record drawings.
Land & sites
Combined building and topographical survey where a scheme spans structure and site.
For your whole team
Our drawings are used by architects, engineers and surveyors as the foundation for design, planning and construction.
When do you need a measured building survey?
Commission one at the start of any project where accurate existing drawings matter:
- Extensions, loft and basement conversions — before your architect starts designing.
- Planning applications — for the aligned ‘existing’ and ‘proposed’ drawings councils require.
- Listed building consent — accurate record drawings of a protected building, often alongside building height work.
- Lease plans — compliant, scaled plans for registering a lease at HM Land Registry.
- Refurbishment & fit-out — a reliable baseline for costing and coordinating works.
Getting the survey done early is almost always the cheapest route — it’s the first sensible step on any building project.
Measured Building Survey London
Blackacre Chartered Surveyors & Valuers delivers precise measured building surveys for architects, developers, and homeowners in London and the South East. We use advanced 3D laser scanners to produce detailed floor plans and elevations.
Accurate As-Built 2D CAD Drawings & 3D Models
Our detailed measured surveys provide the exact dimensions of structural walls, heights, windows, and services, offering a solid base for architectural design, spatial planning, and building refits.
Frequently asked questions
A measured building survey records the building’s dimensions and produces scaled CAD/BIM drawings for design and planning. A building survey (RICS Level 2 or 3) assesses condition — damp, movement, defects. They answer different questions, and for a renovation you often need both.
Because they’re traced from laser-scan data, we typically achieve room accuracy of 1–3mm, with final drawings comfortably within the ±5mm the industry works to — far more reliable than hand measurement or estate-agent plans.
2D drawings in DWG/DXF (AutoCAD) as standard, with Revit/BIM models where needed, plus PDFs for easy viewing. We can also supply the raw point cloud in formats such as .e57, .rcp, .las and .pts. If your architect has a preferred format, tell us at the brief stage.
Yes. Laser scanning is non-contact and works around occupation and awkward geometry — we’ve surveyed everything from flats to heritage structures, including a Grade II* windmill. Furnished buildings need more scan positions, which we factor into the quote.
Yes. We can combine the building scan with GNSS data on the same visit to deliver a topographical survey of the site, georeferenced to OS coordinates and height above mean sea level.
It helps. When your architect specifies the level of detail and outputs they need, the right information is captured first time. If you haven’t appointed one yet, we can advise on what’s likely to be needed for your project type.
Your key contact
Ben Salvage MRICS C.Build E MCABE
Director | Chartered Building Surveyor
Need accurate as-built drawings?
Tell us about your building and project and we’ll turn a precise laser scan into the drawings your design team needs — across London, Surrey and Sussex and the wider UK.
London: 107–111 Fleet Street, London EC4A 2AB · Sussex: Curtis House, 34 Third Avenue, Hove BN3 2PD