Guide
Measured survey specification: detail levels, laser scanning and BIM
Updated
The specification is where measured survey fees are genuinely decided, and where clients most often buy the wrong thing. This is what the choices mean, in plain terms, and what each does to the fee.
The specification is an agreement, not a grade
RICS professional guidance on measured surveys (Measured surveys of land, buildings and utilities) frames the survey around a detail and accuracy specification agreed between client and surveyor: what is captured, to what tolerance, and how it is presented. A reputable firm will put that specification in writing before quoting, and will promise only the agreed accuracy and detail, not a universal grade. Treat any promise of unqualified accuracy with suspicion; every survey has a stated tolerance and scope.
Deliverables, from cheapest to most capable
- 2D CAD drawings
- Floor plans, then elevations and sections as added scope. The baseline for extensions and planning work, and the cheapest route; a typical house sits in the £400–£900 range (typical 2026 fees).
- Point cloud (laser scan)
- A dense 3D capture of the building as scanned. Fast on site and complete as a record, but raw clouds are not drawings: budget for modelling or drawing extraction on top, which is where much of the cost sits.
- BIM model (scan to BIM)
- The point cloud modelled into an information model to an agreed level of detail. The most capable deliverable and the most expensive: modelling time scales steeply with the level of detail specified, so agree it precisely, not "full BIM".
Writing a brief that gets you the right fee
- State the purpose. "Existing drawings for a planning application" and "fit-out coordination model" imply different specifications; let firms propose the lightest one that serves the purpose.
- List the outputs by name. Plans, elevations, sections, roof plan, point cloud, model, and the file formats your designer wants.
- Agree detail and accuracy in writing. Ask each firm to state the specification their fee assumes, then compare fees against the same specification, see the cost guide.
If your architect has not asked for BIM, you probably do not need it for a domestic project; 2D CAD to an agreed specification remains the standard product for house extensions. Get quotes stating your purpose and let firms propose the right specification.