Part 2A of the Building Regulations explained
The dutyholder and competence regime for building work in England: who the five dutyholders are, what designers must do under regulations 11J and 11K, what competence means, and what changes on higher-risk buildings and at completion.
What is Part 2A of the Building Regulations?
Part 2A of the Building Regulations 2010 is the dutyholder and competence regime that has applied to building work in England since 1 October 2023. It places legal duties on five dutyholders to plan, manage and monitor work so it complies, and requires everyone carrying out design or building work to be competent for it.
Part 2A (regulations 11A to 11Q) was inserted by the Building Regulations etc. (Amendment) (England) Regulations 2023 (SI 2023/911), made under the Building Safety Act 2022. It is not limited to higher-risk buildings. It applies to almost all building work covered by the Building Regulations, from a house extension to a tower. Higher-risk buildings carry extra requirements on top, but the core duties are the same.
The roles deliberately mirror the Construction (Design and Management) Regulations 2015, but the purpose is different. CDM is about health and safety; Part 2A is about compliance with the Building Regulations. Our guide to the CDM and Building Regulations principal designer covers how the two fit together.
- 11A–D
Clients and appointments
Client arrangements (11A), higher-risk information (11B), domestic clients (11C), appointing a PD and PC (11D).
Client - 11E–I
Competence
Checking before appointing (11E), the general requirement (11F), PD and PC competence (11G, 11H), loss of competence (11I).
Everyone - 11J–N
Duties
General duty (11J), plus additional duties for designers (11K), contractors (11L), the PD (11M) and the PC (11N).
All dutyholders - 11O–Q
Admin
Change of dutyholder (11O), the minor work exemption (11P) and interpretation, including what "design" means (11Q).
Process
Seventeen regulations in four groups. Most practices only need to know 11J, 11K and 11F day to day, but the client and appointment rules decide who holds which duty.
Part 2A applies in England. Wales introduced its own equivalent, Part 2B of the Building Regulations 2010 as they apply in Wales, from 1 July 2026, with roles aligned to CDM and competence duties for all building work. Practices working on both sides of the border should check the Welsh Government guidance.
Who are the dutyholders and what must each do?
The five dutyholders are the client, the principal designer, the principal contractor, designers and contractors. The client sits at the top; the principal designer runs the design phase and the principal contractor runs the construction phase.
Where more than one contractor is involved, regulation 11D requires the client to appoint a principal designer and principal contractor in writing. If it does not, it carries those duties itself.
- Client
- Makes suitable arrangements for planning, managing and monitoring the project, including sufficient time and resources (11A). Provides building information to designers and contractors and cooperates with them.
- Domestic client
- Someone having work done on their own or a family member's home. Under 11C their duties pass to the contractor or principal designer; if no appointments are made, the designer or contractor in control of each phase takes on the role. Work that is only minor work listed in Schedule 4 is exempt from the client duties (11P).
- Principal designer
- Plans, manages and monitors design work and coordinates it so the design would comply if built (11M). Makes sure designers cooperate and comply, and liaises with the principal contractor. Our principal designer duties guide covers this in detail.
- Principal contractor
- The mirror-image duty for building work in the construction phase (11N): plan, manage and monitor it, coordinate contractors and liaise with the principal designer.
- Contractors
- Make sure their building work complies, supervise and instruct their workers, cooperate and share information, and report concerns to the principal contractor (11L).
What must designers do under Part 2A?
Regulation 11J sets the general duty: take all reasonable steps to ensure that design work would, if built, comply with all relevant requirements, and cooperate with the client and other dutyholders. Regulation 11K adds five specific duties.
"Design" is defined widely in regulation 11Q to include drawings, design details, specifications, bills of quantities and calculations prepared for the design. Anyone preparing or modifying these is a designer, including architects, engineers, technologists, specialist subcontractors and specification writers.
The five regulation 11K duties
- Check the client knows its duties first. A designer "must not start design work unless satisfied that the client is aware of the duties". A short written note at appointment, such as in the appointment letter or a client briefing note, is a sensible way to evidence this.
- Design for compliance. Take all reasonable steps to ensure the design, if built, would comply with all relevant requirements.
- Provide sufficient information about the design, construction and maintenance of the building to help the client, other designers and contractors comply. For architects this lands squarely on drawings and specifications.
- Report concerns about others' work. Where working on only part of the design, review the related design work and report compliance concerns to the principal designer.
- Advise on higher-risk status if asked by the principal designer or client.
These duties sit with individual designers regardless of who the principal designer is.
A specification that names a product which does not meet the requirement is a Part 2A issue for the designer who wrote it, not only a quality issue.
What are the competence requirements?
Regulation 11F requires anyone carrying out design or building work to be competent. For individuals that means the skills, knowledge, experience and behaviours necessary for the work; for organisations it means organisational capability.
Individuals
"The skills, knowledge, experience and behaviours necessary" for the work they carry out.
Organisations
Management policies, procedures, systems and resources so the individuals they control are competent and trainees are supervised.
A practice can employ competent people and still fall short if it has no system for supervising trainees or allocating work to people able to do it.
The duties also run the other way
- Before appointing anyone, regulation 11E requires the appointer to take all reasonable steps to satisfy themselves of the appointee's competence. On higher-risk building work they must also ask about serious sanctions in the previous five years.
- Refuse what you cannot do. A person must not carry out work they are not competent to carry out.
- Report loss of competence. Under regulation 11I, anyone who stops meeting the competence requirements must notify whoever appointed them.
- Principal designer and principal contractor have specific tests in regulations 11G and 11H, and organisations in those roles must name a competent individual to manage the role.
Government guidance points to PAS 8671 (principal designers) and PAS 8672 (principal contractors) as recommended competence standards, while noting that meeting them does not guarantee legal compliance.
What changes on higher-risk buildings?
On higher-risk building work in England, Part 2A applies alongside the Building (Higher-Risk Buildings Procedures) (England) Regulations 2023. Appointments move earlier, competence checks must be recorded, and change control and declarations are added.
On higher-risk buildings, changes of dutyholder are reported to the Building Safety Regulator under the higher-risk procedures instead of the 14-day notice.
What happens at completion and when dutyholders change?
For work that is not higher-risk, regulation 16(4A) requires the completion notice to include signed statements from the client and from each principal designer and principal contractor. Where a statement cannot be provided, the reasons must be given.
The client signs that, to the best of their knowledge, the work complies. Each principal designer and principal contractor signs that they fulfilled their Part 2A duties. A dutyholder asked to sign needs a record that supports the statement. That is the practical consequence of Part 2A for most practices: compliance has to be evidenced, not assumed.
- BEFORE DESIGN
Client briefed
Designer satisfied the client knows its duties (11K).
- APPOINTMENT
Competence checked
Appointer takes reasonable steps first (11E).
- ANY CHANGE
Notify in 14 days
New client, PD or PC reported to the authority (11O).
- ROLE ENDS
28-day document
Outgoing PD or PC sets out its arrangements; the replacement reviews them.
- COMPLETION
Signed statements
Client, PD and PC sign with the completion notice (16(4A)).
Every step produces something that can be shown later. The signed completion statements are only as strong as the records behind them.
Where Avoice fits
Part 2A turns compliance into something each dutyholder must be able to show. That needs a record of which requirements apply, who is responsible and what evidence supports each one.
The Building Regs Tracker in the Avoice Compliance module records which requirements apply to each part of the design, who is responsible and what evidence shows compliance. That gives designers a way to demonstrate their regulation 11K duties and gives the principal designer a single view across packages. QA/QC review checks specifications and drawings against each other before issue.
Software can record and cross-check. The designers, principal designer and client still carry the duties and sign the statements.
Evidence your Part 2A duties as you design
Track which requirements apply to each part of the design, who owns them and where compliance is evidenced, in one view for every package.
This guide is for general education and is not legal or professional advice. Check the current text of Part 2A on legislation.gov.uk and the government guidance before relying on it for a project.