When the UK construction industry talks about BIM maturity, it uses a framework of four levels — Level 0 through to Level 3. These levels describe how collaboratively and how digitally a project team is working. Understanding where your organisation currently sits, and where your clients expect you to be, is the starting point for any serious BIM programme.
This guide walks through BIM levels explained clearly and practically — what each level means, what it requires in practice, and where the international standard ISO 19650 fits into the picture. If you are new to BIM entirely, start with our primer: What Is BIM?
Why Do BIM Levels Exist?
The BIM maturity model was originally set out in the Bew-Richards wedge diagram, published as part of the UK BIM Strategy in 2011. Its purpose was to give the industry a common language for describing digital maturity — and to provide a clear target (Level 2) for the government’s 2016 BIM mandate.
The levels are not certifications or accreditations. They are a framework for understanding where a project or organisation sits on a spectrum from isolated CAD files to fully integrated, data-driven collaboration.
Level 0: Unmanaged CAD
At Level 0, there is no collaboration in any meaningful sense. Design information lives in 2D CAD drawings produced by individual disciplines and exchanged — if at all — as paper prints or unstructured PDF files.
Most organisations moved away from Level 0 practice years ago, but pockets remain, particularly in maintenance and legacy estate management where older workflows have never been updated.
In practice: No shared environment. No version control. Information exchanged by email or post. High risk of coordination errors.
Level 1: Managed CAD and Some 3D
Level 1 introduces a degree of structure. Disciplines may use 3D modelling tools, but they work in isolation. There is typically a Common Data Environment (CDE) of some kind — often a shared file server or basic project extranet — but there is no genuine collaboration between models.
Standards and naming conventions begin to appear at this level (often following BS 1192:2007), but they are applied inconsistently across the team.
In practice: Drawings have version control. Files are shared on a managed platform. 3D models may exist but are not federated across disciplines. Coordination still happens largely through traditional drawing reviews.
Level 2: Collaborative BIM (The UK Mandate)
Level 2 is the current benchmark for UK public-sector project delivery. It is what the government’s 2016 BIM mandate requires, and it is the level that most large clients now specify as standard.
At Level 2, each discipline produces its own 3D BIM model using its own authoring software. These models are federated — brought together in a coordination environment (such as Autodesk Navisworks) — where they are checked for clashes and coordinated across the full design team.
What defines Level 2 is not the technology itself but the process:
- A defined set of information requirements (the Employer Information Requirements, or EIR)
- A project-specific BIM Execution Plan (BEP) agreed by all parties
- A Common Data Environment with managed workflows and approval gates
- Structured, classifiable asset data delivered at handover
Level 2 is governed by a suite of British Standards — most notably PAS 1192-2 and PAS 1192-3 — which have since been superseded by ISO 19650, the international equivalent.
In practice: Federated model coordination. Clash detection reports. Structured handover data. CDE with approval workflow. BEP in place from project start.
Level 3: Integrated BIM (iBIM)
Level 3 is the aspirational end state — a single, shared, integrated model accessible to all project participants simultaneously, with full interoperability across disciplines and supply chain tiers.
In practice, Level 3 is not yet fully realised at industry scale. It requires genuinely open data standards (such as IFC — Industry Foundation Classes), a legal and contractual framework that supports shared model ownership, and a level of platform interoperability that is still maturing.
The direction of travel is clear — and cloud-based platforms such as Autodesk Construction Cloud and Bentley iTwin are moving the industry progressively closer. But for most organisations today, achieving Level 2 consistently and well is the immediate priority.
In practice: Single shared model environment. Real-time access across all disciplines. Full data interoperability. Still emerging at industry scale.
Where Does ISO 19650 Fit In?
ISO 19650 is the international standard for managing information over the whole life cycle of a built asset, published in two main parts:
- Part 1 covers concepts and principles
- Part 2 covers the delivery phase of construction assets
ISO 19650 effectively codifies the processes required for Level 2 BIM into an internationally recognised framework. It replaces the PAS 1192 series in the UK and provides a common language for BIM delivery internationally.
If your clients require ISO 19650 compliance, they are essentially asking for Level 2 BIM delivered within a structured, standards-compliant information management framework. The two are not different requirements — they describe the same target in different vocabulary.
Where Does Your Organisation Sit?
Most construction firms operating in the UK today are somewhere between Level 1 and Level 2 — using 3D authoring tools, with some collaborative workflows in place, but without the consistent process, structured data, and CDE discipline that genuine Level 2 delivery requires.
Closing that gap is not a technology problem. It is a process and capability problem — one that requires a clear BIM Execution Plan, defined roles, and consistent information management discipline across the project team.
At DTT Pro, we help organisations assess their current BIM maturity, identify the specific gaps, and implement the processes needed to deliver Level 2 BIM confidently and consistently. Our BIM consultancy services include maturity assessments, BEP development, and ongoing delivery support. Contact us to discuss a BIM readiness assessment for your business.
Further reading: UK BIM Framework — ISO 19650 Guidance — the definitive UK resource on BIM levels and standards. BSI: PAS 1192 and ISO 19650 — standards background from the British Standards Institution.
