BR Principal Designer Duties Explained (Regulation 11M)

principal designer duties building regulations

The Building Safety Act and subsequent changes to the Building Regulations have transformed how you manage design risk and compliance in England. One of the most important changes is the creation of the Building Regulations Principal Designer role and the detailed duties set out in Regulation 11M of the Building Regulations 2010.

If you act as client, architect, engineer, project manager or contractor, you now need to understand principal designer duties under the building regulations, how they differ from CDM duties, and what they mean in day-to-day practice. Getting this wrong can expose you to regulatory enforcement, delay, cost, and reputational risk. Getting it right gives you a clear line of sight that the design, if built, will comply with all relevant building regulations.

This article explains principal designer duties under building regulations in plain language. It focuses on Regulation 11M, sets the dutyholder duties in context, and gives you practical steps to demonstrate compliance on real projects.

1. Where Regulation 11M fits in the new dutyholder regime

Regulation 11M sits within a new Part 2A of the Building Regulations 2010 which introduces dutyholders and competence requirements for all projects in England.

In summary:

Clients must make “suitable arrangements” to plan, manage and monitor the project so it complies with “all relevant requirements” of the Building Regulations (Reg 11A).

Clients must appoint a principal designer and principal contractor where more than one contractor is, or is likely to be, involved (Reg 11D).

All dutyholders must be competent, which means individuals must have appropriate skills, knowledge, experience and behaviours, and organisations must have the right organisational capability (Reg 11F).

Regulation 11M then sets out additional duties that apply specifically to the BR Principal Designer.

The key idea behind principal designer duties building regulations is simple. There must be a clearly identified party who plans, manages and monitors the design work so that, if the building is built in accordance with that design, the building work will comply with the Building Regulations.

2. What is a BR Principal Designer under Regulation 11M?

Under Regulation 11D, the client must appoint “a designer with control over the design work” as principal designer when there is more than one contractor on the project. That principal designer may be:

An architectural practice

A multidisciplinary consultant

A specialist designer with overall control of the design

The lead designer under a design-and-build contractor

The same organisation might already act as CDM principal designer. Regulation 11D allows the client to “certify” that the CDM principal designer is also appointed as BR principal designer, provided this is done in writing.

However, principal designer duties under building regulations are not health and safety duties. They focus on ensuring compliance with the technical requirements of the Building Regulations, including structure, fire safety, access, services, energy, and other Parts of Schedule 1.

3. Core duty 1: plan, manage and monitor the design work

Regulation 11M(1)(a) requires the principal designer to “plan, manage and monitor the design work during the design phase.”

In practice you should:

Establish a clear design management plan at project start

Define compliance responsibilities across the design team

Set out how you will track compliance risks, decisions and assumptions

Sequence design activities to allow early resolution of high-risk issues (especially fire and structure for higher-risk buildings)

Implement a review and checking regime proportionate to project risk

You must do more than coordinate drawings. The regulator expects an auditable process that shows you identified relevant Parts of the Building Regulations, allocated them to competent designers, and checked that the emerging design is capable of compliance.

For example, for a medium-rise residential scheme, principal designer duties building regulations should include documented design reviews covering:

Structural robustness (Part A)

Fire strategy (Part B)

Resistance to moisture and contaminants (Part C)

Ventilation and indoor air quality (Part F)

Conservation of fuel and power (Part L)

Security of dwellings (Part Q), where applicable

You should record decisions, departures from guidance, and the reasoning behind any performance-based solutions.

4. Core duty 2: coordinate design for compliance with all relevant requirements

Regulation 11M(1)(b) and (2)(b) require the principal designer to coordinate design work so that “all reasonable steps” are taken to ensure that, if the building work is built to that design, it will comply with all “relevant requirements” of the Building Regulations.

Key practical actions:

Identify relevant requirements

Map out which Parts of Schedule 1 apply to the project. These will vary depending on building use, height, and location, but will usually include Parts A, B, C, E, F, G, H, J, L, M and, where relevant, Parts O, Q, R and S.

Capture this in a project-specific compliance matrix.

Allocate responsibilities

Allocate each requirement to a “lead designer” (for example, fire engineer for Part B, structural engineer for Part A).

Make sure every requirement has an identified owner and a defined deliverable (for example, fire strategy report, SAP/SBEM outputs, access statement).

Coordinate between disciplines

You then coordinate across disciplines so that compliance decisions in one area do not undermine another. For example:

A change to façade materials for energy performance must not compromise external fire spread or cavity barrier strategy.

Service penetrations must align with fire compartmentation and acoustic performance.

Changes to layouts for access and use (Part M) must still support means of escape (Part B).

Principal designer duties under building regulations requires proactive management of these interfaces, not just a late coordination check.

5. Core duty 3: drive cooperation and ensure others comply

Regulation 11M(2)(a) and (2)(c) require the principal designer to take “all reasonable steps” to ensure that designers and others involved in design work:

Cooperate with the client, principal designer, principal contractor and each other

Comply with their own duties under the Regulations

You cannot delegate this entirely to others. You should:

Set expectations in appointments and scopes

Make cooperation and information sharing explicit obligations

Run regular design coordination meetings with compliance as a standing agenda item

Challenge incomplete or non-compliant design outputs

Escalate concerns to the client where designers fail to engage

This is central to principal designer duties building regulations. The regulator will ask how you ensured that each designer understood their regulatory duties and how you responded when they did not.

6. Core duty 4: liaise with the principal contractor

Regulation 11M(3) requires the principal designer to liaise with the principal contractor and share any information relevant to:

Planning, managing and monitoring the building work

Coordinating building work and design work to ensure compliance with the Building Regulations

In practice this means:

Sharing design risk registers and compliance trackers

Providing clear design intent documents, details and specifications

Highlighting areas where construction quality is critical for compliance (for example, cavity barriers, fire stopping, airtightness)

Explaining the assumptions in performance-based designs so the principal contractor can plan suitable methods and quality control

Principal designer duties under building regulations continue during the construction phase where design changes occur. You must remain engaged so that any design variations, value engineering or contractor proposals do not undermine compliance.

7. Core duty 5: handover and change of principal designer

Regulation 11M(5) introduces a specific documentation duty. When the principal designer’s appointment ends, they must, “no later than 28 days” after the end of the appointment, give the client a document explaining the arrangements they put in place to fulfil their Regulation 11M duties.

That document should at least:

Describe how you planned, managed and monitored the design work

Explain how you coordinated compliance with the relevant requirements

Summarise key design risks and any outstanding issues at the point of handover

Identify any critical assumptions that future designers or contractors must respect

Where a new principal designer is appointed, Regulation 11M(6) requires them to review these arrangements and take all reasonable steps to ensure ongoing compliance.

You should treat this as a controlled, documented handover process. Poor or absent handover is likely to attract regulatory criticism, especially on higher-risk buildings.

8. Interaction with competence and serious sanctions

Principal designer duties building regulations sit alongside competence requirements in Regulations 11F and 11G and the “serious sanction” provisions in Regulation 11E.

You must:

Demonstrate you, and your organisation, have the skills, knowledge, experience, behaviours and organisational capability to act as principal designer

Put in place internal arrangements to manage the principal designer function, including design leadership, technical review and quality management

Be able to evidence how you assessed competence before taking on the appointment

For higher-risk building work, clients must ask potential appointees about serious sanctions in the previous five years, including compliance notices for Parts A and B, stop notices, and relevant convictions. This directly affects your ability to win principal designer appointments.

9. What this means for clients, designers and contractors

For clients

As client, you must:

Decide early who will act as BR principal designer

Appoint them in writing before construction starts, or before the higher-risk building application to the regulator

Check their competence and record the steps you took

Give them access to the information they need, including surveys, constraints and strategic decisions

You cannot treat principal designer duties building regulations as a tick-box exercise. If you fail to appoint, you automatically inherit the principal designer duties yourself.

For designers

As designer, you must:

Confirm the client understands their duties before you start design work (Reg 11K)

Provide designs that, if built, would comply with the Building Regulations

Provide enough information on construction and maintenance to help others comply

Flag concerns about compliance to the principal designer

If you also act as principal designer, you must clearly separate your “own design” tasks from your wider design management and coordination role, and document how you fulfil both.

For contractors

As contractor or principal contractor, you must:

Plan, manage and monitor building work so it complies with the Building Regulations (Reg 11N)

Cooperate with the principal designer, respond to information requests and share relevant site learning and buildability feedback

Make sure any design-related proposals, changes or temporary works are properly designed and checked for compliance

Principal designer duties under building regulations depend on active engagement from contractors as well as consultants.

10. Practical steps to evidence compliance with Regulation 11M

To demonstrate that you meet principal designer duties building regulations you should put in place a structured approach that leaves a clear audit trail. For example:

Governance and appointments

Clear appointment letter or scope defining your role as BR Principal Designer

Competence statement referencing relevant experience, systems and technical capability

Named individual designated to manage the principal designer function in your organisation

Compliance matrix and design responsibility schedule

Project-specific matrix of applicable Parts of the Building Regulations

Allocation of each requirement to a lead discipline or designer

Record of design routes (Approved Documents, British Standards, assessments, performance-based justifications)

Design reviews and checks

Scheduled compliance reviews at key design stages

Technical checklists and peer review records

Logged issues, actions and closure decisions

Interface and change control

Process for assessing the compliance impact of changes

Formal sign-off, including fire and structure, for significant variations

Coordination meetings with principal contractor to manage buildability and technical risk

Handover records

Regulation 11M(5) handover document at the end of your appointment

Summary of residual risks, open issues and key assumptions

This kind of evidence will support you in any regulator interaction and will also give your client confidence that you are discharging principal designer duties building regulations in a robust way.

FAQs Principal Designer Duties Building Regulations 11M

What is the main purpose of Regulation 11M?

Regulation 11M sets out the additional duties of the BR Principal Designer. Its main purpose is to ensure that the design is planned, managed, monitored and coordinated so that, if the building is built to that design, the building work will comply with all relevant requirements of the Building Regulations.

Who can act as BR Principal Designer?

Any designer with control over the design work can act as principal designer, provided they are competent under Regulations 11F and 11G. This may be an architect, engineer, multidisciplinary practice, or a design-and-build contractor’s design arm. The client must appoint them in writing.

Is the BR Principal Designer the same as the CDM Principal Designer?

Not automatically. The same organisation can fulfil both roles, and Regulation 11D allows the client to certify that the CDM principal designer is also appointed as BR principal designer. However, principal designer duties under building regulations focus on compliance with the Building Regulations, not construction health and safety law.

When must a BR Principal Designer be appointed?

Where more than one contractor is, or is likely to be, involved in the project, the client must appoint a BR Principal Designer. For higher-risk building work that goes to the regulator, the client must make the appointment before submitting the building control approval application. For other work, the appointment must be made before the construction phase starts.

What happens if the client does not appoint a Principal Designer?

If the client fails to appoint a BR Principal Designer (or replacement where an appointment ends), the client automatically assumes the duties of the principal designer under the Building Regulations until a competent person is appointed.

Does the Principal Designer’s duty continue during construction?

Yes. Principal designer duties building regulations apply to design work, including design changes during construction. The principal designer must liaise with the principal contractor, review proposed changes, and ensure that revised designs remain capable of compliance.

What documentation must the Principal Designer provide when their appointment ends?

Regulation 11M(5) requires the principal designer to give the client, within 28 days of the end of their appointment, a document explaining the arrangements they put in place to fulfil their duties under Regulation 11M.

Conclusion: Translating Legal Duties into Practical Compliance

The changes to the Building Regulations create a clear and demanding role for the BR Principal Designer. Regulation 11M expects you not only to “coordinate” but to actively plan, manage and monitor the design so that it is capable of compliance, to drive cooperation across the team, and to work closely with the principal contractor throughout the project.

If you act as principal designer, you should treat principal designer duties building regulations as a core professional service line, supported by structured processes, clear documentation, and competent people. If you are a client, you should appoint a principal designer early, check their competence, and insist on a clear compliance strategy and evidence trail.

By doing this you protect residents, users and your own organisation, and you put your projects on a solid footing in a much more demanding regulatory environment.

Contact

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For more information on all aspects of the BR Principal Designer role see the collection of articles in our blog.

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