As-built drawings record what was actually installed, where it runs and how it connects, including every change made after the shop drawings were approved. They are the documents the building owner, facility manager and future contractors rely on once you have left site. Good MEP as-built handover depends on one habit: capture changes as they happen on site, and update the drawings or model regularly, instead of rebuilding the record at the end from memory. This guide sets out what a complete as-built set contains, a checklist you can use before handover, and how to organise the work, whether you draft in-house or use as-built drawing services.
The required content and format of the handover set come from your contract, the client's requirements and any authority requirements for the project. Check those first. This guide covers the practical side.
Why as-builts slip
As-builts are usually the last deliverable and the first to lose resources. The people who know where the services changed move to the next project. Site mark-ups sit in folders, on phones and in emails. By the time drafting starts, nobody is sure which redline is the latest. The result is rework, delayed handover and, sometimes, a delayed final payment.
What an MEP as-built set should show
- The installed route, level and size of pipes, ducts and containment
- Equipment locations and identification matching the labels on site
- Valves, dampers, access panels and isolation points
- Risers, shafts and penetrations through walls and floors
- Changes from the approved shop drawings, with the reference to the instruction or approval that allowed them
- Schematics and riser diagrams that match the installed layout
- Revision history showing the as-built status on every sheet
How to produce as-builts, step by step
- Read the handover requirements early. Confirm the drawing list, formats (native files, PDF or both), model requirements, title block and revision conventions from the contract and the client.
- Set up one source of truth. Keep the latest approved shop drawings or model in one controlled location, with a drawing register.
- Agree how site changes are captured. Decide who marks up changes, in what form (redlined prints, marked-up PDFs or photos with notes), and where they are stored.
- Link each change to its approval. Record the site instruction, RFI response or variation behind each change, so the as-built shows what was approved and not just what was done.
- Update the drawings in cycles. Incorporate mark-ups at a regular interval agreed with the site team, not only at the end.
- Coordinate across trades. Where services share a ceiling space or riser, check that each trade's as-built agrees with the others, using a federated model in Navisworks where one exists.
- Check against site. Have the site supervisor walk key areas against the draft as-builts before the set is finalised.
- Issue the handover set. Apply the as-built status, title blocks and revision references required, and issue with a transmittal and register.
Drawings, model or both
Check whether the handover needs 2D drawings, a model, or both. If a Revit MEP model is required, the model and the sheets drawn from it must tell the same story. Update the model first and regenerate the sheets, rather than editing sheets on their own. If only 2D drawings are required but the project was coordinated in a model, decide early whether the as-built model will be maintained or frozen at a given stage, and record that decision so nobody assumes the model is current when it is not.
Keeping a mark-up log
A simple mark-up log saves more time than any software. For each change, record the date, area, trade, a short description, the approval reference, who marked it up and whether it has been drafted. Review the open items at each site coordination meeting. When the log shows no open items, the drafting is up to date.
As-built drawings checklist
Run this before you issue the handover set:
- Drawing list matches the contract or client requirements
- Every sheet uses the client's title block and as-built revision status
- All site mark-ups have been incorporated, and the mark-up log is closed
- Each change traces to a site instruction, RFI or approved variation
- Equipment tags on drawings match the labels on site
- Valves, dampers, access panels and isolation points are shown
- Schematics and riser diagrams match the plan drawings
- Penetrations and shaft routes are shown and agree with other trades
- Layers, naming conventions and file structure follow the client's standards
- Native files and PDFs are both provided, if required
- The register and transmittal list every drawing and revision issued
Who does what at handover
| Task | Usually owned by | What goes wrong if it is missed |
|---|---|---|
| Recording site changes | Site supervisor or engineer | Changes are lost when people move on |
| Linking changes to approvals | Project engineer or QS | The record shows unapproved work as final |
| Updating drawings and model | Modeller or drafter | Drafting backlog builds up at the end |
| Cross-trade coordination | BIM coordinator | Trades' as-builts conflict in shared spaces |
| Site verification | Site supervisor | Drawings do not match the installation |
| Document control and issue | Document controller | Wrong revisions are handed over |
Common mistakes
- Starting at the end. Rebuilding the as-built set from memory after completion is slower and less accurate.
- Mark-ups in too many places. Redlines spread across emails, chats and paper get missed. Keep one log.
- Copying shop drawings and renaming them. A shop drawing with an as-built stamp is not an as-built.
- No link to approvals. Without references, nobody can tell an approved change from an unapproved one.
- Ignoring the client's templates. A set in the wrong title block or layer structure is often returned.
- Trades out of step. Fire protection, ACMV and wet services in the same ceiling must agree.
- No site walk. Drawings checked only in the office miss what is actually installed.
Outsourcing as-built drafting
As-built work suits a dedicated drafter because it runs alongside construction and depends on knowing the project's history. Give the drafter the latest model or drawings, the mark-up log, the approvals register and the client's templates, and name one person on site to answer questions. Keep site verification and sign-off in-house. For the commercial side of change records, see outsourcing MEP estimation. If the project also needs fire protection design, see fire alarm design in Singapore.
What to send an outsourced drafter
- The latest approved shop drawings or model, with the drawing register
- The mark-up log and all redlines, in one shared location
- The approvals register: site instructions, RFI responses and variations
- The client's templates, title blocks, layer standards and naming conventions
- The handover requirements from the contract
- The name of one person on site who answers queries
How Newham can help
Newham provides dedicated BIM modellers and drafters who prepare as-built documentation, shop drawings and coordination models in Revit MEP, AutoCAD and Navisworks, working in your templates, title blocks and naming conventions. They cover fire protection, ACMV, ELV and wet services (plumbing and sanitary), and keep record drawings up to date as the project changes rather than leaving them to handover. A dedicated drafter is billed monthly in SGD, with no recruitment or setup fees and the scope confirmed in writing. See shop drawing services, or book a discovery call to plan your drafting capacity.