Who the dutyholders are
- Client: must make suitable arrangements for planning, managing and monitoring the project so the work complies, appoint a principal designer and principal contractor where more than one contractor is involved, and give information to the team.
- Principal designer: plans, manages and monitors the design work for compliance and coordinates designers.
- Principal contractor: plans, manages and monitors the building work for compliance and coordinates contractors.
- Designers and contractors: must comply, cooperate and share information.
These roles sit alongside, but are separate from, the CDM 2015 roles of the same name, which concern health and safety. Often the same firm holds both.
Competence
Anyone carrying out design or building work must have the skills, knowledge, experience and behaviours to do it in compliance with the Building Regulations, and anyone appointing them must take reasonable steps to check this. Higher-risk buildings have additional requirements and a separate gateway regime with the Building Safety Regulator.
Domestic clients
Where the client is a homeowner having work done that isn’t for a business, most of the client duties are carried out by the contractor (or the principal contractor where there’s more than one). The homeowner should still cooperate and provide information. See homeowners and builders.
Contracts
JCT 2024 forms identify the principal designer and principal contractor for these purposes, and in the Design and Build Contract a failure to meet the dutyholder obligations is a contractor default. Read what changed in JCT 2024.
General information, not legal advice. What applies to you depends on your contract, the facts and where the work is, and the law changes. Check the sources below and take advice from a qualified professional before acting on anything that matters.
Last updated: 22 September 2026
