Quality & Inspections · Mandatory · Completion
As-Built Drawing Register
A register of as-built drawings showing the final installed condition of all works.
Last reviewed: 29 March 2026 — This guide reflects UK law as of this date. CDM 2015 / Contract remains current with no amendments enacted as of 29 March 2026. Next scheduled review: 29 March 2027.
| Legal basis | CDM 2015 + Contract / BIM Protocol (ISO 19650) + Building Safety Act 2022 |
| What as-builts are | Record the building as actually constructed, incorporating all changes, variations, and deviations |
| CDM 2015 | H&S file must include as-built drawings, especially structural, MEP, and buried services |
| Building Safety Act | Golden thread of digital information for HRBs must include as-built information |
| What to capture | All M&E systems, structural elements, buried services, design changes, access routes, concealed elements |
1. As-Built Drawings — The Building's DNA at Completion
As-built drawings are the permanent record of the building as constructed. They incorporate every change, variation, and deviation from the original design drawings, providing an accurate representation of what was actually built. Inaccurate or missing as-builts create risk and cost for decades — every future maintenance, alteration, or refurbishment project depends on them.
The as-built drawing register tracks the status of every drawing from design issue through to final as-built version, recording which drawings have changes, who is responsible for preparing the as-built version, and whether it has been handed over. Under CDM 2015, as-built drawings form a critical part of the Health and Safety file. Under the Building Safety Act 2022, they contribute to the golden thread of building information for higher-risk buildings.
Update during construction, not at handover
Update as-built drawings during construction, not retrospectively at handover — changes are too easy to forget. Mark up drawings as variations occur and maintain the register throughout the project.
2. As-Built Drawing Register — Content
The register must track every drawing that requires an as-built version, recording the status of each from initial design drawing through to final as-built issue and handover. It provides a single view of as-built progress across all disciplines and identifies drawings where changes have been made that must be captured.
| Column | Description |
|---|---|
| Drawing number | Original drawing number from the design issue |
| Drawing title | Full title of the drawing as issued |
| Discipline | Design discipline — architectural, structural, mechanical, electrical, civil, landscape |
| Changes made? | Whether the as-constructed condition differs from the design drawing — yes or no |
| Change description | Brief description of the changes between design drawing and as-built condition |
| As-built drwg ref | Reference number of the as-built version of the drawing, if different from the original |
| As-built status | Current status — not started, in progress, complete, issued for review, approved |
| Prepared by | Name and organisation responsible for preparing the as-built drawing |
| Format | File format of the as-built drawing — PDF, DWG, DGN, Revit, IFC |
| CDE location | Location of the as-built drawing in the Common Data Environment or document management system |
| Handed over | Whether the as-built drawing has been formally handed over to the client or building owner |
| H&S File | Whether the drawing has been included in the CDM Health and Safety file where required |
3. Common Mistakes
Starting compilation in the final week before handover
As-built drawings must be compiled progressively throughout construction, not in a last-minute rush before handover. Retrospective compilation relies on memory, incomplete records, and guesswork. Changes made months earlier will be forgotten or inaccurately recorded.
Providing design drawings as as-built when changes were made
Issuing the original design drawing as the as-built version when the constructed condition differs is a fundamental failure. Every variation, site instruction, and design change must be reflected in the as-built drawing. The register must confirm whether changes were made and whether they have been captured.
Not including buried services
Buried services — drainage, below-ground ducts, foundations, ground beams — are the most critical elements to record accurately because they cannot be seen once covered. As-built survey and drawing must be completed before backfilling. This is a CDM 2015 Health and Safety file requirement.
Missing M&E coordination drawings
Mechanical and electrical services are frequently rerouted during construction to resolve coordination clashes. The as-built drawings must reflect the actual routing, not the design intent. M&E subcontractors must be contractually required to provide as-built drawings of their installed systems.
Not handing to building owner, including only in H&S file
As-built drawings must be handed directly to the building owner or operator as a standalone deliverable, not buried within the Health and Safety file where they may not be found. The building owner needs as-built drawings for ongoing maintenance, alteration planning, and future works.
4. Frequently Asked Questions
What are the Building Safety Act 2022 requirements for as-builts?▾
The Building Safety Act 2022 requires a golden thread of structured digital information for higher-risk buildings. This must include as-built information that accurately reflects the building as constructed, and it must be maintained and handed over to the building owner. The golden thread must be kept up to date throughout the building's life, not just at completion.
Who prepares as-built drawings?▾
Responsibility is typically split by discipline. The main contractor prepares civil and structural as-builts. M&E subcontractors prepare as-builts for their installed mechanical and electrical systems. The architect prepares architectural as-builts. Each party must be contractually required to deliver as-built drawings as a condition of final account agreement.
What format should as-built drawings be in?▾
PDF for viewing and printing. DWG or DGN for editing and future design use. Revit models or IFC files for BIM-managed projects. The contract or BIM protocol should specify the required formats. Best practice is to provide multiple formats so that the building owner has both a viewable and an editable version of each drawing.
How long should as-built drawings be retained?▾
For the life of the structure — never discard as-built drawings. They are required for every future maintenance activity, alteration, refurbishment, and demolition. Under CDM 2015, the Health and Safety file including as-built drawings must be retained and made available to anyone carrying out future construction work on the building.
Generate your As-Built Drawing Register on Construction Suite
Construction Suite walks you through every required section with a guided Q&A — built to CDM 2015 / Contract — and generates a professionally formatted document in minutes.
Get started freeThis guide is for general informational purposes only and does not constitute legal advice. While every effort is made to ensure accuracy, regulations change and individual project circumstances vary. Construction Suite is a trading name of Xzist Digital Ltd, registered in England and Wales.