CDM 2015: who am I on this job?
Pro Site Docs · Free finder · No sign-up
Answer six questions and get your CDM 2015 role or roles - client, domestic client, designer, principal designer, principal contractor, contractor, worker - with the regulation numbers and what you must do first.
The duty holders in CDM 2015
The Construction (Design and Management) Regulations 2015 name six duty holders and treat workers as a seventh. The client is anyone having construction work done for them - a business, a landlord, a developer, a public body (regulation 4). A domestic client is having work done on their own home, not in connection with a business, and their duties pass automatically to the contractor or principal contractor (regulation 7). A designer is anyone who prepares or modifies a design, which includes an architect, an engineer, a temporary works designer, and a contractor who changes a detail on site (regulation 9). Where there is more than one contractor, the client appoints a principal designer to coordinate the pre-construction phase (regulation 11) and a principal contractor to run the construction phase (regulations 12 to 14). Every contractor plans, manages and monitors their own work (regulation 15). And workers must cooperate, report danger and take care of themselves and others (regulation 8(4) and (5), and section 7 of the Health and Safety at Work etc. Act 1974).
Why people end up holding roles they did not expect
Because the roles follow what you do, not what your contract calls you. A builder who prices a job for a homeowner, sketches the layout and brings in an electrician and a plasterer is a designer, a principal contractor, and the holder of the client's duties - three roles, one van. A client who never gets round to appointing a principal designer holds those duties themselves under regulation 5(3). A subcontractor who moves a beam to suit their pipework has become a designer for that change. The finder works from the answers, not the job title, for that reason.
Appointments in writing
On any project with more than one contractor the client must appoint the principal designer and principal contractor in writing, as soon as practicable and before the construction phase begins (regulation 5(1) and (2)). If they do not, a commercial client carries the duties (regulation 5(3) and (4)); on a domestic project the designer and the contractor in control take the roles by default (regulation 7(2)). Either way the duties exist from the start - the letter just makes clear who holds them. Our CDM 2015 explained guide covers each role in detail, and the CDM duties checker turns the role into the documents the job needs.
FAQs
Who are the duty holders under CDM 2015?
Clients, domestic clients, designers, principal designers, principal contractors, contractors and workers. The client appoints a principal designer and principal contractor in writing whenever more than one contractor is involved; on a domestic project the client's duties pass to the contractor or principal contractor under regulation 7.
Am I a designer under CDM 2015?
If you prepare or modify a design for construction work - drawings, specifications, bills of quantities, temporary works, or a change made on site - yes. Regulation 9 requires you to eliminate or reduce foreseeable risks in the design and to pass on information about the risks that remain.
What happens if no principal designer is appointed?
On a commercial project the client carries the principal designer's duties themselves until they appoint one (regulation 5(3)). On a domestic project the designer in control of the pre-construction phase is the principal designer by default (regulation 7(2)).
Is a landlord a domestic client?
No. A domestic client is having work done on a home they or a family member live in, not in connection with a business. A landlord, a developer or a housing association is a commercial client with the full duties under regulation 4.
Get the documents ready-made
Once you know the role, you know the documents. The CDM 2015 templates cover each duty holder - pre-construction information and appointment letters for the client, the construction phase plan for the principal contractor or sole contractor, the health and safety file for the principal designer.
Construction phase plan, pre-construction information, appointment letters, F10 checklist, design risk register and health and safety file structure - editable Word documents.
See the CDM templatesBuilt by Pro Site Docs from the HSE guidance and regulations named on the page. Published 3 September 2026. It is a planning aid, not a substitute for a competent person's assessment of the actual work.
Keep reading
General guidance only. This article explains how the rules generally work in UK construction. It is not advice for your specific site, task or project, and it is not legal advice. Your own risk assessment, method statement and arrangements must be prepared and checked by a competent person for the actual work being done.