As-built drawings record a building as it actually exists, not as it was drawn. That distinction matters more than it sounds. Design drawings describe intent. As-builts describe reality: the wall that moved 300mm during construction, the services that were rerouted around an obstruction, the mezzanine a previous tenant added and nobody documented.
Anyone planning work in an existing building eventually needs them, and discovers the drawings they have do not match the site they are standing in.
When a Singapore project needs them
The trigger is usually one of these:
- Alteration and addition works. Design cannot start properly without knowing what is there. Assumptions made from outdated drawings surface as variations later, at the worst possible time.
- Fit-out and renovation. Measured drawings of the existing space, before anyone commits to a layout.
- Handover documentation. A record of what was actually built, for the owner or the incoming facilities team.
- Building records for strata and managing agents. Older buildings often have no usable drawing set at all.
- Coordination and clash detection. A BIM team needs something dimensionally reliable to model against.
Where the drawings come from
Traditionally: someone with a tape measure, a laser distance meter and a notebook, walking the building and drafting from their notes. It works, and for a small and simple space it is often the right call. It also scales badly. A day of measuring produces a day of measurements, and anything not measured on the day is a return visit.
Scanning inverts that. 3D laser scanning captures the whole space at once, whether or not anyone knew in advance which dimensions would matter. The output is a point cloud: millions of measured points, each with a real position, forming a complete geometric record of the building as it stands.
Drawings are then produced from that record. Floor plans, elevations, sections, reflected ceiling plans: all cut from the same dataset, all consistent with each other, because they all come from the same measurement.
The practical difference shows up in the questions you did not think to ask. If someone queries a beam soffit height three weeks later, the answer is already in the data. No second visit.
What you get
| Deliverable | Format | Typical use |
|---|---|---|
| Floor plans | DWG, PDF | Design, tender, records |
| Elevations and sections | DWG, PDF | Design, approvals |
| Reflected ceiling plans | DWG, PDF | M&E and fit-out coordination |
| BIM model | RVT, IFC | Coordination, clash detection |
| Point cloud | E57, LAS, LAZ, RCP | Reference for any of the above |
Agree the level of detail before work starts. "As-built drawings" covers everything from a single dimensioned floor plan to a fully modelled building with services, and the difference in effort between those is very large. Being specific up front is the main thing that keeps a scope honest.
Where the output needs to be a coordinated model rather than drawings, the same capture feeds a Scan-to-BIM workflow: the point cloud becomes the reference a Revit or IFC model is built against.
What drives the cost
- Floor area, though not linearly: mobilisation is a fixed cost, so small jobs cost more per square metre than large ones.
- Level of detail. A plan showing walls, openings and levels is a different job from a model including services and structure.
- Access and occupancy. An empty floor scans quickly. An operating warehouse, a live retail unit, or a building only available after hours does not.
- Complexity. Plant rooms, exposed services and irregular geometry take longer to capture and considerably longer to draft.
- Turnaround. Compressed programmes cost more.
On the archived plans
Buying the approved plans from the authority is often the first thing people try, and sometimes it is enough. Two things to know before relying on it.
Approved plans show what was approved, which is not always what was built. And they will not show alterations made after completion, which for a building of any age is usually where the discrepancies live. For older stock the archived records may also be incomplete or difficult to read.
If the building has been altered, or you need dimensional confidence rather than a historical record, scanning is the more direct route. Check what the authority holds first, for current fees and eligibility, go to BCA's Plan Purchase System directly, since the figures quoted on third-party sites are frequently out of date.
Getting a quote
What we need to price a job: the address, roughly how much floor area, what the drawings are for, and whether the space is occupied. Photographs help. If you have any existing drawings, however old, send those too.
If it is a large or unusual building, we would rather look at it before quoting than guess.