As-built drawings show what was actually built, not what was designed. This guide covers the three kinds, redline, record and measured, what a set includes, how they are created, and what to specify before you order.
As-built drawings are the final drawings of a project. They show what was actually built, not what was originally designed. During construction, walls move, pipe routes change, equipment gets swapped and details get adjusted on site. The as-built set records all of it, so owners, facility teams and the next design team work from the building as it stands, not from an old plan.
Why as-built drawings matter
Design drawings show intent. As-built drawings show reality, and most expensive mistakes on existing buildings come from confusing the two.
They are used to plan renovations without opening up walls to check what is behind them, to find valves, panels, dampers and shutoff points during maintenance, and to prove at handover what was built and what changed along the way. A project can be built well and still cause years of friction if it was recorded badly.
The three kinds of as-built drawings
Not all as-builts are worth the same trust. What separates them is how the information was captured.
| Type | How it is made | What it can be trusted for |
|---|---|---|
| Redline as-builts | The contractor marks changes on the construction set during the build, traditionally in red | A history of reported changes. Only as good as the markups, and nobody re-measures the building afterwards |
| Record drawings | The architect or engineer compiles the redlines, change orders and approved substitutions into a clean set | A reliable project record. Still based on what was reported, not on what was measured |
| Measured as-builts | The building itself is measured, today usually with a laser scan, and drawings or a Revit model are built from that data | The only type verified against the building. The safe starting point for renovation and fit-out design |
If new work will be designed from the drawings, that difference is not academic. A redline set can tell you a wall was moved. A measured set tells you exactly where it stands now.
What an as-built set includes
A complete set covers every meaningful change from the construction documents:
- Architectural: final wall, door and window locations, ceilings, room layouts, access panels
- Structural: columns, beams, foundations, slab openings, embeds and framing changes
- Mechanical: duct routes, HVAC equipment, diffusers, dampers and mechanical rooms
- Electrical: panels, conduit routes, lighting, devices and cable trays
- Plumbing and fire protection: pipe routes, valves, cleanouts, risers, sprinkler heads and standpipes
- Site and civil: buried utilities, drainage, grading and manholes
- The paper trail: revision notes, dates and the RFIs and change orders behind each update
Watch for vague notes. Entries like "similar" or "field verified" with no dimension behind them are a warning sign, not documentation.
How as-built drawings are created
There are two routes, and they produce different levels of certainty.
From redlines. The team starts from the latest approved construction set. Field changes are marked up as the work happens, along with RFIs, change orders and substitutions. At the end, a drafting team cleans the markups into a final set, checks sheet references and notes, and hands it over. This is the cheaper route, and it works when the markups were kept honestly and the building matches them.
From a laser scan. A scanner captures the building as a point cloud, a dense 3D measurement of everything visible. Modelers then build the drawings, or a full Revit model, directly from that data. This is the Scan to BIM workflow. The model is checked back against the point cloud before delivery, and the output can be PDF, DWG, Revit or IFC files. This route costs more, and it is the one to use when the existing drawings are missing, incomplete or known to be wrong, because the building itself becomes the source.
Who creates as-built drawings
In most projects, trade contractors create the redlines for their own work, the general contractor collects them, and the architect or engineer compiles the record set. Measured as-builts are usually produced by a scanning or BIM team, such as our 3D scanning and reality capture team, working from site capture through to the finished model.
Who owes what is set by the contract and the closeout requirements. It is worth checking those requirements while the project is still running, because redlines that were never kept cannot be reconstructed later.
Accuracy: what to specify before you order
"Accurate" on its own means nothing. Before ordering as-built documentation, pin down three things:
- How it will be captured. Tape and existing drawings, or a laser scan verified against survey control points.
- What tolerance is guaranteed. Stated as a number, for example within a set number of millimetres, not described in general terms. The industry reference here is the U.S. Institute of Building Documentation's Level of Accuracy (LOA) specification: LOA30, the level most renovation sets are produced to, means the drawings sit within 5 to 15 mm of the real position at a 95 percent confidence level.
- What level of detail you need. For a BIM deliverable, agree the LOD up front: LOD 200 covers approximate size and location, LOD 300 is precise enough for coordinated design, and LOD 350 adds the connections between disciplines that contractors rely on. Each level is defined in the BIMForum LOD Specification.
Agree the deliverable formats at the same time, and ask to see one sample sheet or model area before the full set is produced. That single check catches most misunderstandings while they are still cheap to fix. And set LOD system by system, not as one number for the whole building; our 7 checks before you pay for a BIM model explain why that one detail decides whether the model is usable.
What drives the cost
There is no honest flat rate for as-built drawings, because the work changes completely with the building. The main drivers are the floor area, the number of disciplines included, and the condition of the existing records. Cleaning up a good CAD set is a different job from starting with nothing. Capture method matters too: a new laser scan costs more than redline cleanup, and higher accuracy or a higher LOD takes more modeling time. Occupied buildings and restricted areas take longer to capture than empty ones.
Anyone quoting a firm price without seeing the building or the existing drawings is guessing, and the guess usually gets corrected later at your expense.
When do you need as-built drawings
The common triggers are a renovation or fit-out being planned, project closeout and handover, a facility team taking over maintenance, and a building being bought, sold or leased with poor records. Some owners and public agencies also require as-built documentation as part of the project record. In every case, the drawings are cheapest to produce while the project team and site access are still in place.
Frequently asked questions
Are as-built drawings and record drawings the same thing? Not exactly. As-built usually refers to the contractor's marked-up record of what was built. Record drawings are the clean set the architect compiles from those markups at closeout. People use the terms loosely for both, which is why it pays to ask how a set was produced before relying on it.
How much do as-built drawings cost? It depends on the floor area, how many disciplines are included, and how the information is captured. Redline cleanup is the cheapest route. A scan-based set costs more because it includes the survey itself, but it also removes the risk of designing from wrong drawings. A real quote needs the scope first.
How long does it take to produce as-builts from a scan? Field capture is usually the fast part. A building can often be scanned in days, depending on size and access. The modeling and drafting that follows takes the bulk of the time, and it scales with floor area and the level of detail required.
What format will I receive the drawings in? That is agreed before work starts. Common deliverables are PDF sets for reference, DWG files for CAD work, and Revit models where the as-builts will feed design or facility management. The point cloud itself can also be handed over.
Our building has no drawings at all. Can as-builts still be made? Yes, and it is a common starting point. With no reliable records, the building is measured directly and the drawings are built from the scan. Nothing about the process depends on old drawings being available.
The short version
As-built drawings are the record of what a building actually is. How far you can trust that record depends on how it was captured: reported, compiled, or measured. If the set will be used to design new work, measured as-builts from a laser scan are the version worth paying for, because every decision after that point is built on them. If that is where your project stands, talk to our team about a measured survey and model for your building.
