Designers carry legal duties under CDM 2015 whether or not they think of themselves as a duty holder. The obligations sit in Regulation 9, they apply to anyone who prepares or modifies a design for construction work, and they exist because the cheapest place to remove a hazard is the drawing board — not the site.
Regulation 9 has four subsections. That is worth stating plainly, because designer duties are often described in vaguer and longer terms than the Regulations actually use.
A jurisdiction note. Regulation 3 applies CDM 2015 "in Great Britain". Northern Ireland has its own instrument — the Construction (Design and Management) Regulations (Northern Ireland) 2016, in operation since 1 August 2016 — so if you work there, check the NI position rather than assuming the regulation numbers cited here apply.
Who counts as a designer
Wider than most people assume. A designer is not only the architect. Anyone who prepares or modifies a design — or arranges for or instructs someone under their control to do so — is a designer under CDM 2015. In practice that includes structural and services engineers, architectural technologists, quantity surveyors specifying materials, and contractors carrying out design work, which is where the surprise usually lands.
A specialist subcontractor producing a temporary works design, a cladding shop drawing, or an M&E installation layout is doing design work and picks up Regulation 9 duties for it. Design-and-build arrangements put a principal contractor squarely in the designer role for the parts they design.
If you instruct a change on site that alters how something is built, you have modified a design.
The four duties in Regulation 9
Regulation 9(1) — check the client knows their duties. "A designer must not commence work in relation to a project unless satisfied that the client is aware of the duties owed by the client under these Regulations."
This is a gate on starting, not a background courtesy. It exists because CDM 2015 makes the client responsible for the arrangements that make safe design possible — appointments, information, time and resources — and a client who does not know that will not provide them. On commercial projects it is usually discharged by issuing HSE's client guidance at appointment and recording that you did.
Regulation 9(2) — eliminate foreseeable risk through design. When preparing or modifying a design the designer "must take into account the general principles of prevention and any pre-construction information to eliminate, so far as is reasonably practicable, foreseeable risks to the health or safety of any person—(a) carrying out or liable to be affected by construction work; (b) maintaining or cleaning a structure; or (c) using a structure designed as a workplace."
Note the three categories. The duty is not limited to the people who build it. It covers whoever later cleans the windows, replaces the plant, or works in the finished building. A design that is safe to construct and impossible to maintain safely has not satisfied Regulation 9(2).
Regulation 9(3) — reduce, control, inform. "If it is not possible to eliminate these risks, the designer must, so far as is reasonably practicable—(a) take steps to reduce or, if that is not possible, control the risks through the subsequent design process; (b) provide information about those risks to the principal designer; and (c) ensure appropriate information is included in the health and safety file."
The hierarchy is explicit: eliminate first, then reduce, then control. Jumping straight to "we'll note it as a residual risk" skips two steps the regulation requires you to attempt.
Regulation 9(4) — provide information with the design. "A designer must take all reasonable steps to provide, with the design, sufficient information about the design, construction or maintenance of the structure, to adequately assist the client, other designers and contractors to comply with their duties under these Regulations."
"With the design" is the operative phrase. Information that arrives separately, later, or on request has not been provided with the design.
What competence is required
Regulation 9 does not set the competence standard — Regulation 8(1) does, and it covers designers explicitly: a designer "appointed to work on a project must have the skills, knowledge and experience, and, if they are an organisation, the organisational capability, necessary to fulfil the role that they are appointed to undertake." Regulation 8(2) adds that they "must not accept an appointment to a project unless they fulfil the conditions in paragraph (1)."
That is a duty on the designer to decline work they are not competent for, not only a duty on the client to check.
Designer versus principal designer
A frequent confusion. Every designer on a project has Regulation 9 duties. The principal designer is one designer, appointed by the client on projects with more than one contractor, who additionally plans, manages and monitors the pre-construction phase under Regulation 11 and prepares the health and safety file under Regulation 12(5).
So the principal designer carries Regulation 9 duties for their own design work plus the coordination duties on top. A designer who is not the principal designer still owes everything in Regulation 9 — they simply do not coordinate the others.
For the coordination role in depth, see our principal designer duties guide.
What a principal contractor should expect from the design team
If you are the principal contractor rather than the designer, Regulation 9 tells you what should already have happened before you price or build:
- Residual risk information supplied with the design, not on request (9(4)). If a design arrives with no risk information, ask — it is owed to you.
- Evidence that elimination was attempted before a risk was passed down as something for you to manage on site. A residual-risk register full of items that could have been designed out is a Regulation 9(2) question.
- Maintenance and cleaning access considered, because 9(2)(b) and (c) put those in scope and they are the ones most often skipped.
- Health and safety file content flowing from the designers via the principal designer (9(3)(c)).
Where a subcontractor is doing design work — temporary works, specialist installations — those Regulation 9 duties travel with them, and the competence check under Regulation 8(3) should reflect that they are being appointed as a designer as well as a contractor.
Common failures
- Contractor-designers not recognising the role. A specialist producing shop drawings has Regulation 9 duties and often no awareness of them.
- Risk registers instead of design changes. Recording a hazard is not eliminating it. Regulation 9(3) only permits reduce-and-control where elimination is not reasonably practicable.
- Information issued late. 9(4) requires it with the design.
- Maintenance ignored. The commonest single gap — designs safe to build, difficult to clean or service safely.
- Regulation 9(1) skipped entirely on projects with inexperienced or domestic-adjacent clients, which is exactly where it matters most.
For the full duty-holder map, see CDM duty holders explained; for the client's side of Regulation 9(1), our CDM client duties guide; and for the regulation-by-regulation structure, our CDM 2015 regulations summary.
SubComply is being built for the contractor side of CDM compliance — tracking competence evidence, insurance and documents across your subcontractors, including the specialists doing design work. Join the waitlist to be notified when it launches.
Sources
- The Construction (Design and Management) Regulations 2015 (SI 2015/51), Regulation 9
- The Construction (Design and Management) Regulations 2015 (SI 2015/51), Regulation 8
- The Construction (Design and Management) Regulations 2015 (SI 2015/51), Regulation 3 (application in Great Britain)
- The Construction (Design and Management) Regulations (Northern Ireland) 2016 (SR 2016/146)
- HSE L153 — Managing health and safety in construction: CDM 2015. Guidance on Regulations
This guide is for informational purposes and does not constitute legal advice. For project-specific CDM compliance questions, consult a qualified health and safety professional.
Last reviewed: 14 October 2026