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Last edited 25 Aug 2026

As-built drawings and record drawings

[edit] Introduction

In modern construction projects, the gap between design intent and final construction reality is inevitable. Site conditions, unforeseen challenges, and necessary modifications during construction mean that the original design drawings rarely represent the completed building accurately. This is where as-built drawings and record drawings become essential documentation for project success and future facility management.

[edit] Understanding the Difference

While often used interchangeably, as-built drawings and record drawings serve distinct purposes:

As-built drawings are the marked-up construction documents that capture changes made during the building process. Contractors typically annotate the 'final construction issue' drawings on-site using red ink to highlight modifications, additions, or deviations from the original design.

Record drawings (sometimes called 'as-constructed' drawings) are the formal, professionally updated drawings that incorporate all as-built information, creating a comprehensive record of what was actually constructed. These serve as the definitive reference for the completed project.

[edit] Why As-Built Documentation Matters

[edit] Legal and Compliance Requirements

Record drawings are often mandatory components of:

Health and Safety Files.
Operation and Maintenance (O&M) manuals.
Building handover documentation.
Regulatory compliance records.

[edit] Facilities Management

Accurate as-built documentation is critical for:

Future renovation and modification planning.
Maintenance and repair operations.
Space planning and tenant improvements.
Emergency response planning.

[edit] Hidden Infrastructure Challenges

One particularly problematic area is the documentation of concealed systems. Under-floor cabling in commercial offices exemplifies this challenge - successive tenants often cut and abandon their predecessors' cables while installing new systems. Without accurate cabling records, this creates significant complications for future occupants who need to understand the existing infrastructure.

[edit] The Traditional As-Built Process

[edit] During Construction

On-Site Marking: Contractors mark changes on construction drawings using red ink.
Specialist Documentation: Trade contractors record installed systems and components.
Progress Updates: Major changes are documented as they occur.
Supplementary Surveys: Additional measurements may be taken for complex areas.

[edit] Post-Construction

Compilation: The consultant team collects all marked-up drawings.
Professional Drafting: Record drawings are created from annotated construction documents.
Quality Review: Documentation is verified against actual installations.
Final Delivery: Complete record drawing sets are provided to the client.

[edit] The Modern Approach: Scan to BIM

[edit] Limitations of Traditional Methods

Traditional as-built documentation processes have inherent limitations:

Human error in manual measurements and markups.
Time-consuming compilation and drafting processes.
Difficulty capturing complex geometric details.
Incomplete documentation of hidden or inaccessible systems.
Inconsistencies between different trade contractors' documentation.

[edit] Laser Scanning Technology

Modern technology has revolutionised as-built documentation through high-precision 3D laser scanning. This approach:

Captures millions of measurement points in minutes.
Creates comprehensive digital records of existing conditions.
Documents complex geometries with millimetre accuracy.
Identifies clashes and conflicts between systems.
Provides a permanent digital record for future reference.

[edit] Building Information Modeling (BIM)

The RIBA Plan of Work 2013 recognised the evolution toward digital documentation, defining 'as-constructed' information as: "Information produced at the end of a project to represent what has been constructed. This will comprise a mixture of 'as-built' information from specialist subcontractors and the 'final construction issue' from design team members. Clients may also wish to undertake 'as-built' surveys using new surveying technologies to bring a further degree of accuracy to this information."

The current RIBA Plan of Work (2020 edition) carries this thinking forward through Stage 6 (Handover), where the Building Manual, Health and Safety File and Fire Safety Information are compiled, and Stage 7 (Use), where facilities and asset management rely on the information handed over. Where a Building Information Model has been created for a project, it should be updated to reflect construction changes and delivered to the client as the Asset Information Model (AIM), in accordance with BS EN ISO 19650, in a format that facilities management teams can continue to develop throughout the building's lifecycle. For higher-risk buildings, as defined under the Building Safety Act 2022, accurate as-built and record information also forms part of the golden thread of information that must be created, kept accurate and handed over into occupation.

[edit] Scan to BIM Services

For projects requiring the highest level of accuracy and detail, Scan to BIM services have emerged as an increasingly common industry approach. This process converts point cloud data from 3D laser scanning into intelligent BIM models that accurately represent the as-built condition. Specialist providers typically offer:

Architecture, structure, and MEP modelling from scan data.
Various Levels of Development (LOD) to match project requirements.
2D drawing extraction from 3D models.
Coordination and clash detection services.
Integration with facilities management systems.

This technology-driven approach helps ensure that record drawings maintain the precision and comprehensiveness required for modern building management.

[edit] Requirements for Quality Record Drawings

The Design Framework for Building Services, 5th edition (BG 6/2018), published by BSRIA, provides specific guidance for record drawings related to building services.

Essential content:

All mechanical, electrical, and public health systems and components.
Locations of ducts, pipes, cables, busbars, and plant items.
Positions of pumps, fans, valves, dampers, and control devices.
Security and fire sensors with control equipment.
Electrical switchgear and components.

Technical specifications:

Scale not less than installation drawings.
Labelled with appropriate sizes, pressures, and flow rates.
Marked access points for operations and maintenance.
Dimensions included only where necessary for location clarity.

[edit] Contractual and Procurement Considerations

[edit] Clear Scope Definition

The requirement to produce as-built drawings and record drawings must be:

Explicitly stated in tender documentation.
Not assumed as part of 'standard' services.
Adequately resourced in project budgets.
Scheduled with realistic timeframes.

[edit] Resource Allocation

Creating comprehensive as-built documentation is time-consuming. Key considerations include:

Adequate retention funds to ensure completion.
Recognition that project teams are eager to move to new projects.
Clear deliverable specifications and acceptance criteria.
Defined responsibilities for each project team member.

[edit] Ongoing Maintenance

The client's facilities management team bears responsibility for:

Keeping record drawings current with future modifications.
Maintaining accessible and organised documentation systems.
Conducting periodic surveys if drawings become outdated.
Integrating records into comprehensive facility management platforms.

[edit] Best Practices for Success

Plan Early: Include as-built documentation requirements in initial project planning.
Define Standards: Establish clear specifications for format, detail level, and delivery method.
Regular Updates: Don't wait until project completion to begin documentation.
Leverage Technology: Consider laser scanning and BIM for complex projects.
Verify Accuracy: Implement quality control processes before final acceptance.
Digital Integration: Ensure compatibility with facility management systems.
Train Teams: Educate all stakeholders on documentation requirements and processes.

[edit] Conclusion

High-quality as-built and record drawings are essential investments in a building's future. They enable efficient facility management, support future modifications, ensure regulatory compliance, and preserve institutional knowledge about the built asset.

As construction technology advances, the integration of laser scanning, BIM and Scan to BIM services creates unprecedented opportunities for accuracy and comprehensiveness in as-built documentation. By embracing these modern approaches alongside traditional best practices, project teams can deliver record drawings that truly serve their intended purpose throughout a building's operational life.

The key is recognising that as-built documentation is not merely a contractual obligation - it is a valuable asset that supports informed decision-making, reduces future costs, and enhances building performance for years to come.

[edit] Related articles on Designing Buildings

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Comments

To contribute to this discussion click 'Add a comment' above and add your thoughts to this page.

Apart from registering on site changes to the engineers' and architect's drawings it is essential that the specialist trade contractors reflect what has been installed on site.

Records of underfloor cabling in city offices is a particular problem because successive tenants cut off but leave in their predecessors cables and providing space is available install their own systems. Without cabling records this can prove a nightmare for say the fourth company to occupy the premises.

There is an issue relating to the method or convention for recording site changes during construction. The issue is that site changes need to be highlighted or made to stand out in order to identify them. This article mentions use of red ink to signify changes, but this is no use when the architectural drawing is a mass or various lines of various colours.

There needs to be a standard way of highlighting changes or revisions on a drawing and it must be easily understood and obvious.

When applying for an amendment of a building warrant it is necessary to show revisions when submitting drawings for local authority approval. These amended drawings should clearly show what has changed from the original approved drawings. This means that as-built drawings alone are not sufficient, unless it is easy to tell what is different from the original approved drawings. The original drawings have presumably already been assessed and approved, so all that needs to be checked is what has changed to ensure the design is acceptable.