Building Regulations in England
Building Regulations Dutyholders and Competence (Part 2A)
TL;DR
Since 1 October 2023, Part 2A of the Building Regulations 2010 has required clients, designers and contractors in England to plan, manage and monitor work so it meets the Building Regulations, and to be competent for it. The roles share CDM 2015 names but differ from them: if you are the only contractor, Part 2A treats you as the principal contractor, and you sign a statement at completion.
This guide is for small builders working in England. It explains who the dutyholders are under Part 2A of the Building Regulations 2010, how those roles differ from the CDM 2015 roles with the same names, what competence means, and what you sign at the end of a job. For approval routes and inspections, see building control for extensions. For your health and safety duties, see CDM 2015 for small builders.
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What Part 2A is and where it applies
Part 2A of the Building Regulations 2010 is called “Dutyholders and competence”. It was inserted by the Building Regulations etc. (Amendment) (England) Regulations 2023 (SI 2023/911) and has applied in England since 1 October 2023.
It gives duties to the people who commission, design and carry out building work. Anyone carrying out building work must make sure the work they carry out, and the work of the workers under their control, is planned, managed and monitored so that it is in compliance with all relevant requirements (regulation 11J(1)). Designers have the equivalent duty for design work (regulation 11J(2)). “Relevant requirements” are the requirements of the Building Regulations listed in regulation 11Q, including Schedule 1, which covers matters such as structure, fire safety, drainage and energy.
Part 2A does not replace building control. You still need the right application or notice and the inspections that go with it.
England only. Wales brought in its own dutyholder and competence rules, Part 2B, from 1 July 2026 through the Building etc. (Amendment) (No. 2) (Wales) Regulations 2025, with different regulation numbers, so check the Welsh rules for work in Wales. Scotland and Northern Ireland have separate building regulations, and Part 2A does not apply there.
Very small jobs. Regulation 11P says a client is not required to comply with Part 2A where the work consists only of work described in Schedule 4. Examples include replacing an external door with no more than half of its internal face glazed, and replacing a WC, washbasin, sink, bath, shower or rainwater gutter, as long as the conditions in Schedule 4 are met. An extension is not Schedule 4 work.
Higher-risk buildings. GOV.UK describes a higher-risk building as at least 7 storeys or 18 metres high, with at least 2 residential units, or a hospital or care home. Work on those buildings carries extra duties that this guide does not cover.
The dutyholders under Part 2A
Part 2A uses the same role names as CDM 2015. The definitions are in regulation 2 of the Building Regulations 2010.
- Client. Any person for whom a project is carried out. The client must make suitable arrangements for planning, managing and monitoring the project, including enough time and other resources, so that the work is in compliance with all relevant requirements (regulation 11A(1)). The client must also give building information to every designer and contractor as soon as practicable (regulation 11A(4)).
- Domestic client. A client for whom a project is carried out that is not in the course or furtherance of the client's business, such as a homeowner having an extension built on their own home. Some of a domestic client's duties are carried out by others, as explained below.
- Designer. Any person who, in the course of a business, carries out design work, or arranges for or instructs someone under their control to do it. Design includes drawings, design details, specifications and calculations (regulation 11Q). A builder who draws up details or specifies products for the job is doing design work.
- Contractor. Any person, including a client but not a domestic client, who in the course of a business carries out, manages or controls building work. A contractor must not start work until satisfied that the client is aware of their duties (regulation 11L(1)). A contractor must make sure their building work is in compliance with all relevant requirements, and give each worker under their control appropriate supervision, instructions and information (regulation 11L(2)).
- Principal designer. Where there is more than one contractor, or more than one is reasonably foreseeable, the client must appoint in writing a designer with control over the design work as principal designer (regulation 11D(1)(a)). The principal designer plans, manages, monitors and co-ordinates the design work (regulation 11M).
- Principal contractor. Where there is more than one contractor, or more than one is reasonably foreseeable, the client must also appoint in writing a contractor with control over the building work as principal contractor (regulation 11D(1)(b)). The principal contractor plans, manages, monitors and co-ordinates the building work during the construction phase (regulation 11N).
For a project that is not higher-risk building work, the appointments must be made before the construction phase begins (regulation 11D(3)(b)). If a business client fails to make an appointment, it must carry out that role's duties itself until it appoints someone (regulation 11D(5)). That fallback does not apply to a domestic client (regulation 11C(3)).
If you are the only contractor
This is where Part 2A differs from CDM 2015: where only one contractor is working on a project, Part 2A treats that contractor as appointed as the principal contractor, and it must fulfil the principal contractor's duties (regulation 11D(6)). The Regulations call this the sole contractor. Under CDM 2015, by contrast, a job with only one contractor has no principal contractor.
Where you are the only contractor and there is only one designer, that designer fulfils the principal designer's duties; if there is more than one designer, they agree in writing which of them will (regulation 11D(7)). The lead designer gives the client a copy of the agreement.
Domestic clients
A homeowner does not carry out the client's arrangement duties in regulation 11A(1) to (3), or the competence checks in regulation 11E(2) to (5), personally. Where there is only one contractor, the contractor carries out those duties (regulation 11C(1)(a)).
Where there is more than one contractor, the principal contractor carries out those duties, unless the homeowner and the principal designer agree in writing that the principal designer will (regulation 11C(1)(b)).
On a job with more than one contractor, if the homeowner does not appoint a principal designer or principal contractor, the designer in control of the design phase is the principal designer and the contractor in control of the construction phase is the principal contractor (regulation 11C(2)).
How the roles compare with CDM 2015
The two sets of roles do different jobs. GOV.UK puts it this way: the CDM roles manage the health and safety of workers and anyone around the site during building work, while the Building Regulations roles make sure design and building work meets the Building Regulations.
The appointments are separate. On a job with more than one contractor, a client can appoint the same firm to both roles, or certify in writing that the CDM principal designer or principal contractor is treated as appointed for the Building Regulations too (regulation 11D(2)). GOV.UK says that where the people in these roles are different under CDM and the Building Regulations, they need to work together and share relevant information.
Two differences matter most for a small builder.
- The only contractor. Here the two sets of rules differ from each other: under CDM 2015 a job with only one contractor has no principal contractor, but under Part 2A that contractor is treated as appointed as the principal contractor (Building Regulations, regulation 11D(6)).
- Competence. CDM 2015 asks for the skills, knowledge and experience, and the organisational capability, to fulfil the role in a way that secures health and safety (CDM regulation 8(1)). Part 2A asks for the skills, knowledge, experience and behaviours, or the organisational capability, to carry out the work in accordance with all relevant requirements of the Building Regulations (Building Regulations, regulation 11F).
The table sets the two side by side. For your CDM duties in full, see CDM 2015 for small builders and principal contractor vs contractor.
| Topic | Building Regulations Part 2A | CDM 2015 |
|---|---|---|
| What the roles are for | Design and building work that meets the Building Regulations | Health and safety of workers and others during the work |
| Written appointments | Client appoints a principal designer and principal contractor in writing where there is more than one contractor, or more than one is reasonably foreseeable (reg 11D(1)) | Client appoints a principal designer and principal contractor in writing where there is more than one contractor, or more than one is reasonably foreseeable (reg 5(1)) |
| A job with one contractor | That contractor is treated as appointed as the principal contractor (reg 11D(6)) | No principal contractor. On a domestic job, the client's duties go to that contractor (reg 7(1)(a)) |
| Domestic client's duties | With only one contractor: the contractor. With more than one contractor: the principal contractor, unless the client and principal designer agree in writing that the principal designer does this (reg 11C(1)) | Same pattern under reg 7(1) |
| Domestic client makes no appointments | Designer in control of the design phase is the principal designer; contractor in control of the construction phase is the principal contractor (reg 11C(2)) | Designer in control of the pre-construction phase is the principal designer; contractor in control of the construction phase is the principal contractor (reg 7(2)) |
| Competence standard | Skills, knowledge, experience and behaviours, or organisational capability, to do the work in accordance with all relevant requirements (reg 11F) | Skills, knowledge and experience, and organisational capability, to fulfil the role in a way that secures health and safety (reg 8(1)) |
What competence means
In plain terms, you must be able to do the work you take on so that it meets the Building Regulations, and you must not take on work you cannot do.
The legal test
- Anyone carrying out building work or design work must have the skills, knowledge, experience and behaviours (for an individual), or the organisational capability (for a firm), to carry out the work in accordance with all relevant requirements (regulation 11F(1)).
- Contractors and designers also need the skills, knowledge, experience and behaviours, or organisational capability, to fulfil their duties under Part 2A (regulation 11F(2)).
- A principal contractor needs the same for the principal contractor's duties (regulation 11H(1)). A firm acting as principal contractor must designate an individual under its control to manage those functions, after taking all reasonable steps to satisfy itself that the person has the skills, knowledge, experience and behaviours to do so (regulation 11H(2) and (3)). GOV.UK says this does not make the individual the principal contractor: the legal responsibilities stay with the firm.
- Organisational capability means appropriate management policies, procedures, systems and resources, so that your people meet the competence requirements and anyone in training is properly supervised (regulation 11Q(3)).
Behaviours
Regulation 11Q(4) says the necessary behaviours include:
- complying with the relevant requirements, including refusing to carry out building work that is not in compliance with them, or design work that cannot be built in compliance;
- co-operating with others on the work;
- refusing work that is beyond your skills, knowledge or experience, and asking others for help where necessary.
Trainees and apprentices
The competence requirements do not apply to an individual who is in training to meet them, but whoever asked the trainee to do the work must make sure they are adequately supervised (regulation 11F(3) and (4)). Someone in training to meet the principal contractor or principal designer requirements cannot be appointed to that role (regulation 11F(5)).
Checking the people you bring in
Before you let anyone carry out building work or design work for you, you must take all reasonable steps to satisfy yourself that they meet the competence requirements, or are a supervised trainee (regulation 11E(2)). You must also take all reasonable steps to satisfy yourself that they can plan, manage and monitor their own work (regulation 11E(3)). A person must not accept work they are not competent to do (regulation 11E(6)).
If you stop meeting the competence requirements during a job, you must tell someone (regulation 11I). If you are the principal contractor or principal designer, tell the client. If you are a contractor on a job with more than one contractor, tell the person who asked you to do the work and the principal contractor. If you are a designer on such a job, tell the person who asked you to do the design work and the principal designer. In any other case, tell the person who asked you to do the work.
How to show competence
Part 2A does not name a competence card, certificate or register that a small builder must hold. No app or software can make you competent. It can only help you keep the evidence. GOV.UK gives examples of how individuals can show competence, such as completing formal training and keeping a portfolio of work that details relevant experience and knowledge. It says trade associations, professional bodies, sector training providers and awarding bodies may be able to help.
For principal designers and principal contractors, GOV.UK points to PAS 8671 and PAS 8672, published by the British Standards Institution, which set out recommended competence requirements. GOV.UK also says that following these PAS standards, or any other standard, does not guarantee meeting all legal obligations.
In practice, a small builder can keep: training certificates and cards for each person; a list of similar jobs completed, with their completion certificates; a note of how apprentices and trainees are supervised; and, for a firm, short written procedures for planning and checking work. On the Pro plan and above, The Site Book can record each worker's cards and certificates with expiry alerts. It does not assess or certify anyone's competence.
What to do on a domestic extension
Here is how Part 2A works on a typical extension for a homeowner, who is a domestic client. It runs alongside your CDM 2015 duties and your building control application.
- Work out who the contractors are. A contractor is any person who, in the course of a business, carries out, manages or controls building work (regulation 2). That includes a self-employed tradesperson carrying out building work for their business.
- If you are the only contractor. Part 2A treats you as appointed as the principal contractor, which differs from CDM 2015 (regulation 11D(6)). As the only contractor, you also carry out the homeowner's duties to make suitable arrangements for the project and to check competence (regulation 11C(1)(a)).
- If there is more than one contractor. The homeowner must appoint a principal designer and a principal contractor in writing before the construction phase begins, as there is more than one contractor (regulation 11D(1) and (3)). If they make no appointments, the designer in control of the design phase and the contractor in control of the construction phase take those roles (regulation 11C(2)). With more than one contractor, the principal contractor carries out the homeowner's arrangement and competence-check duties, unless the homeowner and the principal designer agree in writing that the principal designer will (regulation 11C(1)(b)).
- Make sure the homeowner knows their duties. You must not start until you are satisfied the client is aware of their duties (regulation 11L(1)). GOV.UK says a domestic client must allocate enough time and resource, appoint designers and contractors, co-operate with others and provide the building information they have. A short note with your quote is a practical way to explain this.
- Check the people you bring in. Take all reasonable steps to check the competence of anyone you ask to do building or design work, and supervise trainees (regulations 11E and 11F(4)).
- Plan, manage and monitor the work. Plan, manage and monitor the building work so that it is in compliance with all relevant requirements, and give your workers appropriate supervision, instructions and information (regulations 11J(1), 11L(2) and 11N(1)).
- Work with the designer. As principal contractor you liaise with the principal designer, share information about planning and co-ordinating the work, and have regard to their comments on compliance (regulation 11N(3) and (4)).
- Tell building control about later appointments. If the client appoints a principal contractor (or sole contractor) or a principal designer after the building control application is made or the building notice is given, building control must be told within 14 calendar days of the appointment. For a domestic client, the person appointed gives the notice and says it is given on the client's behalf (regulation 11O). With a registered building control approver, a similar notice goes to the approver within 14 days of the appointment (regulation 17 of the 2024 regulations for registered building control approvers, SI 2024/110).
- Hand over your arrangements. When your appointment as principal contractor ends, give the client a document explaining the arrangements you put in place to fulfil your principal contractor duties, no later than 28 days after the appointment ends (regulation 11N(5)(b)).
- Sign your completion statement. See the next section.
Compliance declarations at completion
Part 2A changed what goes in the completion notice. On the local authority route, the person carrying out the work must give the completion notice no more than five days after the work is completed (regulation 16(4)). It must include (regulation 16(4A)):
- the name, address, telephone number and, if available, email address of the client, the principal contractor (or sole contractor) and the principal designer (or sole or lead designer);
- a statement that the building work is complete;
- a statement signed by the client confirming that, to the best of the client's knowledge, the work complies with all applicable requirements of the building regulations;
- a statement from each principal contractor (or sole contractor) and each principal designer (or sole or lead designer), signed by that person, giving their contact details and the dates of their appointment, and confirming that they fulfilled their duties under Part 2A.
If a statement for one of those people cannot be included, the notice must give the reasons why (regulation 16(4B)).
With a registered building control approver, the client gives the approver a notice with the same statements when the work is complete (regulation 18 of the 2024 regulations for registered building control approvers, SI 2024/110).
Agree early who will prepare the completion notice and collect the statements. Keep the records that let you sign your own statement honestly: what you checked, who did the work and how problems were put right. For the completion certificate itself, see getting your completion certificate.
Part 2A records and your CDM paperwork
Part 2A and CDM 2015 run side by side on the same job. Keep the two sets of records separate but consistent.
- Part 2A records: written appointments or the client's certificate under regulation 11D(2), any lead designer agreement, notices to building control, the competence checks you made, your arrangements document at the end of your appointment and your completion statement.
- CDM 2015 records: the construction phase plan, RAMS, site inductions and welfare arrangements.
The Site Book generates the CDM paperwork, such as RAMS, a construction phase plan and a site induction, for you to review and adjust. See what is a construction phase plan and RAMS for a house extension. It does not prepare Part 2A appointment letters or completion statements.
Common questions
What is Part 2A of the Building Regulations?
Part 2A, called Dutyholders and competence, was inserted into the Building Regulations 2010 by SI 2023/911 and has applied in England since 1 October 2023. It gives clients, designers, contractors, principal designers and principal contractors duties to plan, manage and monitor design and building work so that it meets all relevant requirements of the Building Regulations. It also sets competence requirements for everyone who carries out design or building work.
If I am the only builder on an extension, am I the principal contractor under the Building Regulations?
Yes, under Part 2A. Regulation 11D(6) says that where only one contractor is working on a project, that contractor is treated as appointed as the principal contractor, which differs from CDM 2015, where a job with only one contractor has no principal contractor. You then carry out those duties as well as your duties as a contractor.
Is the Building Regulations principal contractor the same as the CDM principal contractor?
Not automatically. They are separate appointments with different purposes: the CDM role is about health and safety during the work, and the Building Regulations role is about the work meeting the Building Regulations. On a job with more than one contractor, the client can appoint the same firm to both roles, or certify in writing that the CDM principal contractor is treated as appointed for the Building Regulations as well (regulation 11D(2)).
What does competence mean under Part 2A?
For an individual, it means having the skills, knowledge, experience and behaviours needed to carry out the work in accordance with all relevant requirements of the Building Regulations. For a firm, it means having the organisational capability: appropriate management policies, procedures, systems and resources (regulations 11F and 11Q). The behaviours include refusing work that would not meet the requirements, refusing work beyond your skills, knowledge or experience, and asking for help when you need it.
Do I need a competence certificate, or PAS 8672, to build extensions?
Part 2A does not name a certificate you must hold. You must be competent for the work you take on, and be able to show it. GOV.UK gives completing formal training and keeping a portfolio of work as examples of how individuals can show competence. PAS 8671 and PAS 8672 set out recommended competence requirements for principal designers and principal contractors, but GOV.UK says following them, or any other standard, does not guarantee meeting all legal obligations.
What do I sign when the work is finished?
On the local authority route, the completion notice must include a statement from each principal contractor (or sole contractor) and principal designer (or sole or lead designer), signed by that person, giving the dates of their appointment and confirming that they fulfilled their Part 2A duties. The client signs a statement that, to the best of their knowledge, the work complies with all applicable requirements of the building regulations (regulation 16(4A)). If a statement cannot be included, the notice must give the reasons (regulation 16(4B)).
Does Part 2A apply in Wales or Scotland?
No. Part 2A of the Building Regulations 2010 applies in England. Wales brought in its own dutyholder and competence rules from 1 July 2026, with different regulation numbers, so check the Welsh rules for work in Wales. Scotland and Northern Ireland have separate building regulations.
Are there any jobs Part 2A does not cover?
Part 2A applies to projects that include building work. There is one narrow exception for clients: regulation 11P says a client is not required to comply with Part 2A where the work consists only of work described in Schedule 4. Examples include replacing a WC, washbasin, bath or shower, or an external door with no more than half of its internal face glazed, subject to the conditions in that Schedule. An extension is not Schedule 4 work.
What Part 2A asks of a small builder, and what it does not
Pros
- Gives everyone on the job a clear duty to plan, manage and monitor their own work against the Building Regulations.
- Lets a client use the same firms for the CDM 2015 and Building Regulations roles, confirmed in writing.
- Lets trainees do design and building work under adequate supervision while they build competence.
- Ends with signed statements, so everyone knows what they are confirming at completion.
Cons
- Uses the CDM 2015 role names for different duties, which makes the two easy to mix up.
- Does not name a certificate for competence, so you keep your own evidence.
- Adds notices and declarations to the building control paperwork.
- Does not replace building control approval, inspections or your CDM 2015 duties.
“Any individual or organisation that carries out work beyond their competence level or organisational capability can face enforcement action.”
“The principal designer and principal contractor for CDM can also carry out these same roles for building regulations.”
Keep the safety side of the job in order too.
Part 2A is about the Building Regulations. Build the RAMS, construction phase plan and site induction for the same job, and share them with your team.
Sources
- The Building Regulations 2010, Part 2A: Dutyholders and competence — legislation.gov.uk · Accessed 26 October 2026
- The Building Regulations 2010, regulation 2: Interpretation — legislation.gov.uk · Accessed 26 October 2026
- The Building Regulations 2010, regulation 16: Notices in relation to building work — legislation.gov.uk · Accessed 26 October 2026
- The Building Regulations 2010, Schedule 4 — legislation.gov.uk · Accessed 26 October 2026
- The Building Regulations etc. (Amendment) (England) Regulations 2023 (SI 2023/911) — legislation.gov.uk · Accessed 26 October 2026
- The Building (Registered Building Control Approvers etc.) (England) Regulations 2024, regulations 17 and 18 — legislation.gov.uk · Accessed 26 October 2026
- The Building etc. (Amendment) (No. 2) (Wales) Regulations 2025 (SI 2025/1320) — legislation.gov.uk · Accessed 26 October 2026
- Design and building work: meeting building requirements — GOV.UK (Building Safety Regulator) · Accessed 26 October 2026
- Construction (Design and Management) Regulations 2015, regulation 5 — legislation.gov.uk · Accessed 26 October 2026
- Construction (Design and Management) Regulations 2015, regulation 7 — legislation.gov.uk · Accessed 26 October 2026
- Construction (Design and Management) Regulations 2015, regulation 8 — legislation.gov.uk · Accessed 26 October 2026