A Building Regulations Principal Designer, usually shortened to BRPD, is a designer with control over the design work whom a client appoints to plan and coordinate how a project's design meets the Building Regulations. The role sits in the Building Regulations 2010, as amended by the Building Regulations etc. (Amendment) (England) Regulations 2023, which took effect on 1 October 2023 and applies in England. A client must make this appointment where there is more than one contractor, or where it is reasonably foreseeable that more than one contractor will work on the project (regulation 11D). The number of designers only comes into it where a single contractor is involved.
Holding the role does not mean personally guaranteeing that the design complies. The statutory duty is to plan, manage, monitor and coordinate the design work, and to take all reasonable steps to secure compliance, while each designer keeps their own duties for their own work (regulation 11M). In the legislation the role is named simply "principal designer". Industry calls it the Building Regulations Principal Designer, or BRPD, to separate it from the principal designer role under CDM 2015. Those are two separate appointments with separate duties, and they are often confused. Wales has its own regime, covered in the jurisdiction section below.
The dutyholder regime this guide describes is not UK-wide, and the detail differs by nation. In England it sits in Part 2A of the Building Regulations 2010, inserted by the Building Regulations etc. (Amendment) (England) Regulations 2023 (SI 2023/911) and in force from 1 October 2023. For higher-risk buildings in England, the Building Safety Regulator is the building control authority.
Wales has its own version. From 1 July 2026 a separate regime applies under a new Part 2B of the Building Regulations 2010, introduced by the Building etc. (Amendment) (No. 2) (Wales) Regulations 2025. It follows the same shape as England, but the detail differs in ways that can change the answer on a project:
Scotland and Northern Ireland run their own building standards systems and sit outside this regime.
CDM 2015 created a principal designer role focused on health and safety risk: the hazards a design creates for the people who build, use, and maintain a building. The Building Regulations Principal Designer role concerns something else. It is about whether the design, if built, would meet the Building Regulations, from structure and fire safety through to energy and accessibility.
The two roles are often connected in practice. A client does not have to appoint a separate person for the Building Regulations role. Under regulation 11D(2), a client is treated as complying if, instead of appointing someone, they certify in writing that the CDM principal designer is treated as appointed as the principal designer for the purposes of the Building Regulations. The certification route is available, but it does not displace the competence requirements. It works only where the CDM principal designer would independently qualify, since a person who does not meet the competence tests is barred from acting in the role (regulation 11E(7)(a)).
One person can hold both roles on the same project, or the two can sit with different people. Holding both, or certifying one person into both, does not merge them. The health and safety duties and the Building Regulations duties stay distinct, and each is evidenced on its own terms.
The client makes the appointment, in writing, where there is more than one contractor, or it is reasonably foreseeable that more than one contractor will work on the project (reg 11D(1)). The person appointed as principal designer must be a designer with control over the design work.
Where a project has only one contractor, that contractor is treated as the principal contractor automatically, and the client is not required to appoint a principal designer. If there is one designer, that designer carries out the principal designer duties. If there is more than one, the designers agree in writing which of them acts as lead designer, and that lead designer gives the client a copy (reg 11D(7)).
The appointment carries a firm deadline. For a project that includes higher-risk building work needing an application for building control approval to the regulator, the appointment must be made before that application is submitted. For any other project, it must be made before the construction phase begins. Appointing earlier still, before the main design decisions harden, is what makes the role workable in practice.
A BRPD is still a designer, so it carries the general designer duties on top of the principal designer duties: the role is more than coordination. It plans, manages, and monitors the design work during the design phase, with one aim: a design that, if built, complies with all the relevant requirements of the Building Regulations. The design phase is any period during which design work is carried out, and it can continue into the construction phase, so the appointment need not end when work starts on site or when Gateway 2 is passed.
In practice the role means:
As a designer, a BRPD must also not start design work unless it is satisfied the client is aware of the duties the client owes under the Building Regulations (reg 11K). Where a BRPD takes over from an earlier one, it must review the arrangements the previous principal designer had put in place (reg 11M(6)).
These duties are met through the design work as it happens. A clear record of that work is what lets a BRPD show, later, how they were met.
The role carries a competence requirement. Anyone carrying out building or design work must be competent to do it, and that general duty sits in regulation 11F of the Building Regulations 2010. Regulation 11G then adds the requirement specific to the principal designer. An individual acting as BRPD needs the skills, knowledge, experience and behaviours to do the work, and an organisation acting as BRPD needs the organisational capability to match, under regulation 11G(1).
Where the BRPD is an organisation rather than an individual, regulation 11G goes further. The organisation must designate a named individual to manage its functions as principal designer, and before doing so take all reasonable steps to satisfy itself that person has the skills, knowledge, experience and behaviours to manage the role. So even where a practice holds the appointment, a competent individual has to be answerable for the work.
PAS 8671:2022, "Built environment. Framework for competence of individual Principal Designers. Specification", describes what that individual competence looks like, including the higher thresholds expected for work on higher-risk buildings. It is a published specification and a useful competence framework. It is not a British Standard and it is not law. The legal duty is the one in the Regulations, and PAS 8671 is a way to meet and evidence that duty rather than a substitute for it.
Two limits sit alongside this. A person in training may not be appointed as a principal designer, though training with supervision is permitted for design work more broadly (regulation 11F(3) to (5)). And where a BRPD ceases to meet the competence requirements at any point, it must notify the client (regulation 11I).
Competence here is something the client has to be satisfied of, and something the BRPD should be able to evidence.
Some projects carry an extra layer. The thresholds in this section are the English test; the Welsh test, set out in section 02, differs. For the design and construction regime in England, a higher-risk building is one at least 18 metres tall, or with at least 7 storeys, that contains at least two residential units. Hospitals and care homes meeting the same threshold are included during design and construction. How the height and the number of storeys are counted follows technical rules. Height is measured to the top of the floor surface of the top storey, not to the roof or ridge, and roof-top plant levels are left out, so a building that reads as over 18 metres to the ridge can sit under the threshold on the statutory measure (SI 2023/275, reg 5). For the storey count, a storey is left out where it is treated as below ground, which happens if any part of its finished ceiling sits below the adjacent ground level, and certain small gallery levels are also excluded (SI 2023/275, reg 6). This matters on sloping sites and where there are basements.
The exclusions are narrower than they first appear. A building sits outside the regime only where it consists entirely of a secure residential institution, a hotel, or military barracks, or where it contains living accommodation provided by the Ministry of Defence, or for His Majesty's forces, a visiting force, or an international headquarters or defence organisation (SI 2023/275, reg 7). A mixed-use block that holds a hotel alongside two or more residential units is not excluded, so the presence of a hotel does not by itself put a project beyond the regime.
On these projects the design has to pass what the industry calls Gateway 2, which is shorthand rather than a term used in the regulations. The Building Safety Regulator reviews the application, and its approval is required before construction. In England a project may be submitted in stages, so initial groundworks and basement works can be approved and started before the full design for the rest of the building is submitted. The Construction Leadership Council published guidance on staged applications in December 2025, updated in June 2026. The BRPD's evidence feeds the Building Regulations part of that submission, so the state of the record built during design shapes how the review goes.
None of this is discharged by a single document at the end. Compliance shows through a trail: which requirements apply, who was responsible for each, what evidence supports them, and how design changes were handled along the way. Kept as the project runs, that trail is ready when the building control authority asks how the duties were met. Left to the end, it has to be reconstructed from inboxes and old drafts.
COMP³ is built for this role. It takes a project's details and returns the duties that apply, the relevant requirements in play, and the evidence each one needs, then keeps the record as the work proceeds. You can see how it reasons on the features page, and how the underlying regulatory model is checked on the verification page. If you carry a BRPD appointment, the who it's for page shows where it lands hardest.
This guide is general information about the role. It is not legal advice, and it is not a statement of your obligations on a specific project. COMP³ does not replace professional judgement, and the duty to discharge the role stays with the appointed BRPD.