Provisions the documents cite: reg 1 (Wales; in force 1 July 2026) and reg 5 (inserting Part 2B – Wales into the Building Regulations 2010): reg 11R(4)–(5) (building information; cooperation — stay with a domestic client), reg 11T (domestic clients: Wales), reg 11U (appointment of principal designer and principal contractor), regs 11W–11Y (competence: general, principal designer, principal contractor), reg 11Z (ceasing to be competent: notification), reg 11Z8 (interpretation, including organisational capability and the necessary behaviours); Part 2B also contains regs 11R(1)–(3), 11S, 11V and 11Z1–11Z7, including reg 11Z4 (additional duties of a principal designer) and reg 11Z5 (additional duties of a principal contractor)
What it requires
From 1 July 2026 the Welsh dutyholder and competence regime is Part 2B – Wales of the Building Regulations 2010, inserted by these Regulations; it mirrors the English Part 2A (register entry building-regs-2010) with Welsh numbering, and a document for work in Wales must cite Part 2B, not Part 2A. reg 11U — where there is, or is reasonably foreseeable to be, more than one contractor, the client appoints in writing a principal designer and a principal contractor (or certifies that the CDM principal designer and principal contractor are treated as appointed), before the building control approval application for higher-risk building work or otherwise before the construction phase; replacements are appointed as soon as reasonably practicable and the client carries the duties meanwhile; a sole contractor is the principal contractor and a sole or agreed lead designer the principal designer; for higher-risk building work written records of the competence checks are kept (reg 11U(8)–(10)). reg 11T — a domestic client may assign the duties in regs 11R(1)–(3), 11V(2)–(5), 11Z4 and 11Z5 to themselves or to any other person, provided there is a written statement confirming that the person taking them on understands the duties and is able to carry them out, giving the location of the building work and that person's name, address, telephone number and (if available) email address, signed by that person and, where someone other than the domestic client takes them on, also by the domestic client; the statement is given before the building control approval application for higher-risk building work, or otherwise before the construction phase begins; if the domestic client does not assign the duties, those in regs 11R(1)–(3) and 11V(2)–(5) are carried out by the sole contractor or, where there is more than one contractor, by the principal contractor or (where the client and the principal designer agree in writing) the principal designer; if a domestic client fails to make the reg 11U appointments, the designer in control of the design phase is the principal designer and the contractor in control of the construction phase the principal contractor; reg 11U(5) does not apply to a domestic client. Unlike England's reg 11C, a Welsh domestic client can take the client duties on personally. What a Welsh domestic client can take on, and what stays with them — the duties that can be assigned by signed statement under reg 11T(1) are those in reg 11R(1)–(3) (making, maintaining and reviewing suitable arrangements for planning, managing and monitoring the project), reg 11V(2)–(5), reg 11Z4 (the additional duties of a principal designer: planning, managing and monitoring the design work, coordinating it so the design would comply with all relevant requirements, taking all reasonable steps to secure cooperation and compliance by designers, liaising with and sharing information with the principal contractor and having regard to its comments, assisting the client with information on request, and giving the client, within 28 days after the appointment ends, a document explaining the arrangements put in place) and reg 11Z5 (the matching additional duties of a principal contractor for the building work during the construction phase); reg 2 describes a person assigned under reg 11T(1) as including a domestic client who assigns themselves the duties of a principal designer or principal contractor. The reg 11R(4) duty to provide building information — information in the client's possession or reasonably obtainable, relevant to the building work or design work (reg 11R(7)) — as soon as practicable to every designer and contractor, and the reg 11R(5) duty to cooperate, are not assignable under reg 11T(1) and stay with the domestic client (REASONING from reg 11T(1)); if the client assigns nothing, only the reg 11R(1)–(3) and 11V(2)–(5) duties pass to the contractor, principal contractor or principal designer (reg 11T(3)). reg 11W — anyone carrying out building work or design work must have the skills, knowledge, experience and behaviours (an individual) or the organisational capability (an organisation) to do the work in accordance with all relevant requirements and to fulfil their duties as contractor or designer; a trainee is exempt if adequately supervised, but a trainee may not be appointed principal designer or principal contractor. regs 11X–11Y — a principal designer or principal contractor must have that capability for the role, and an organisation must designate a competent individual to manage the function after taking all reasonable steps to be satisfied of their competence. reg 11Z — a person who ceases to meet those requirements notifies the client (if principal designer or principal contractor), or the person who engaged them and the principal designer or principal contractor. reg 11Z8 — organisational capability means appropriate management policies, procedures, systems and resources so that individuals comply and trainees are supervised; the necessary behaviours include refusing non-compliant building or design work, cooperating, and refusing work beyond one's skills, knowledge or experience.
The instrument itself: https://www.legislation.gov.uk/wsi/2025/1320. The summary above is our plain-English reading, not the text of the instrument — always work from the source.
How this entry is kept current
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The 2 documents that cite it
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