Principal Designer (CDM 2015) in London

CDM 2015 places duties on those who design and manage construction work. The Principal Designer coordinates health and safety during the pre-construction (design) phase on projects involving more than one contractor — planning, managing and monitoring design-stage health and safety, and ensuring relevant information flows to those who need it. The aim is to design out foreseeable risks before they reach site.

For domestic clients, duties under CDM are often reduced and can pass to the contractor or principal contractor by default, but they do not disappear — they must be allocated clearly. Where appropriate, we can act as Principal Designer under CDM, confirming the role, scope and terms in a written appointment before work begins. We do not assume the role without that appointment, and we are clear where competence or insurance means a separate appointment is more suitable.

The CDM Regulations apply to all construction work, including domestic home projects, whenever more than one contractor is involved. They require a Principal Designer to plan, manage and monitor health and safety during the design phase, the gathering of pre-construction information, and — for larger jobs, broadly those lasting more than thirty working days with significant numbers on site or exceeding five hundred person-days — formal notification to the Health and Safety Executive. The aim is not paperwork for its own sake but making sure safety is considered by the people best placed to influence it: the designers.

The heart of the Principal Designer’s role is to eliminate or reduce foreseeable risks while a project is still on the drawing board, when changing them costs nothing. That means anticipating how the building will actually be constructed and maintained — working at height, the stability of the structure during the build, the disturbance of asbestos in older homes, access for maintenance — and designing to avoid the hazard rather than leaving it to be managed on site. Risks designed out early are the ones that never have to be controlled later.

There are now two separate "Principal Designer" roles and they are routinely confused. This role — the CDM Principal Designer — is about construction health and safety. The other, introduced under the Building Safety Act, is the Principal Designer for building regulations compliance, a different statutory duty concerned with the design meeting the building regulations. The two can be held by the same person or by different people, but they are distinct appointments with distinct responsibilities, and we are explicit about which we are providing on any given project.

The role is about planning, managing and monitoring health and safety in the pre-construction phase: identifying significant risks, coordinating designers, and helping the right information reach the Principal Contractor. It is not the same as contract administration or full site supervision. We explain the boundaries so homeowners do not confuse three different appointments.

Competence and adequate resources are legal expectations. We will not accept a token appointment that cannot be discharged properly.

Home extensions and refurbishments still create real construction risk: structural openings, work at height, asbestos, public highway interfaces. CDM is not only for commercial sites. We help domestic clients understand when formal PD/PC appointments apply and how designer coordination reduces avoidable harm.

Early hazard information — services, structure, access — belongs in design, not as a surprise on site.

Where we are already architect, a Principal Designer role can be a natural extension if scope and fees are explicit. Where another designer leads, we can still contribute design information without holding the PD duty. Clarity on who holds which duty is itself a safety control.

We set this out in appointment documents before construction information is issued.