CDM Regulations for Designers: Your Duties Under Regulation 9

A practical guide for UK site managers, contractors and small builders.

If you design anything that will be built, altered or maintained, the CDM regulations place duties on you personally. Regulation 9 of CDM 2015 is the one that matters most, and it applies far more widely than most people assume. This guide explains who counts as a designer, exactly what Regulation 9 requires, and how those duties work in practice, so you can meet them without guessing.

Who counts as a designer under CDM 2015

The word designer is defined broadly in the Construction (Design and Management) Regulations 2015. You are a designer if, as part of your business, you prepare or modify a design, or arrange for or instruct someone else to do so. A design includes drawings, specifications, calculations, bills of quantities and design details relating to a structure.

That sweeps in a lot of people who do not think of themselves as designers: architects and engineers, obviously, but also surveyors, contractors who make design decisions on site, temporary works designers, and anyone who specifies materials or methods. If your decisions shape what gets built and how, Regulation 9 applies to you.

What Regulation 9 actually requires

Regulation 9 sets out the duties of designers in relation to health and safety. Read plainly, it asks you to think about risk while you still have a pencil in your hand, because that is when risk is cheapest to remove.

• Do not start unless the client is aware of its duties. A designer must not begin work on a project unless satisfied that the client is aware of the client duties under CDM 2015.
• Eliminate foreseeable risk first. When preparing or modifying a design, you must take into account the general principles of prevention and, so far as is reasonably practicable, eliminate foreseeable risks to anyone building, using, maintaining or eventually demolishing the structure.
• Then reduce or control what is left. Where a risk cannot be eliminated, you must reduce or control it through the design, and provide information about any remaining significant risks.
• Provide information with the design. You must give sufficient information about the design, construction and maintenance of the structure to help the client, other designers and contractors carry out their own duties.
• Cooperate and coordinate. You must cooperate with the principal designer and other duty holders so health and safety is coordinated across the whole project.

The order of the duties matters

Regulation 9 is built around the general principles of prevention, and the sequence is deliberate. You eliminate a hazard before you try to control it, and you only manage a residual risk with information once you have exhausted design changes. A worked example makes this concrete: if a plant room can only be reached by ladder for maintenance, the first move is to redesign the access, not to add a note recommending a harness. The note is the last resort, not the first answer.

Designer versus principal designer

It is easy to confuse the two roles, but they are not the same. Every designer on a project carries the Regulation 9 duties. The principal designer is a single duty holder, appointed by the client on any project with more than one contractor, who plans, manages and coordinates health and safety across the whole pre-construction phase under Regulation 11. In short, a principal designer is also a designer with Regulation 9 duties, plus an extra coordinating role on top. If you are one designer among several, Regulation 9 is your responsibility; coordinating everyone else is not.

What good looks like in practice

Meeting Regulation 9 is less about paperwork and more about a habit of mind carried through the design.

• Risk is designed out early. You review your design for foreseeable hazards to builders, users and maintainers, and change the design to remove them wherever you reasonably can.
• Residual risks are flagged clearly. The significant risks you could not remove are recorded and passed on, not buried in a drawing note nobody reads.
• Information flows to the people who need it. Contractors and the principal designer receive what they need to plan safe construction and future maintenance.

Frequently asked questions

This article is general guidance for UK construction and is not legal advice. For requirements specific to your work, check the full text of CDM 2015 and current HSE guidance, including L153, and your own duty holder obligations.