Principal Designer

Who needs a principal designer?

Most clients discover the principal designer requirement late — usually when a contractor or building control asks who holds the appointment. The law is straightforward: on any project involving more than one contractor, CDM 2015 requires the client to appoint a principal designer in writing for the pre-construction phase; and since the Building Safety Act reforms, a separate principal designer duty exists under the Building Regulations for building control compliance. Fail to appoint, and the duties — and the liability — default to you as the client.

What the appointment covers

• CDM 2015 principal designer — planning, managing and monitoring health and safety in the pre-construction phase: pre-construction information, design risk reviews, co-ordination between designers, and the health and safety file at handover.
• Building Regulations principal designer — the compliance-focused role introduced in 2023: taking reasonable steps to ensure the design, if built, complies with building regulations.
• Client duty advice — F10 notification where required, competence checks on your design team and contractors, and keeping the paperwork inspection-ready.

CDM 2015 and Building Regulations 2023: two duties, one title

The shared name causes real confusion, so it is worth separating the roles. The CDM 2015 principal designer is a health and safety appointment: planning, managing and monitoring the pre-construction phase so the design can be built, maintained and eventually demolished safely. The Building Regulations principal designer was created by the Building Safety Act reforms, through amendments to the Building Regulations that took effect in October 2023: a compliance appointment, responsible for planning, managing and monitoring the design work so that, if built, it would comply with building regulations. The duties are distinct, the appointments are separate, and both must be made in writing on projects with more than one contractor. One professional can — and usually should — hold both, provided they are competent for each. Competence is itself now an explicit requirement: clients must take reasonable steps to satisfy themselves that appointees have the skills, knowledge, experience and, for organisations, the capability the role demands.

The client duties you keep

Appointing a principal designer does not empty the client's own duty list. Clients must still make suitable arrangements for managing the project, allow adequate time and resources for the work to be done safely, ensure welfare provision, and notify HSE on Form F10 where the work exceeds the notification thresholds (broadly, lasting longer than 30 working days with more than 20 workers on site simultaneously, or exceeding 500 person-days). Part of the panel's service is walking clients through this list once, in plain English, so the project file shows each duty discharged rather than discovered.

Domestic projects: what actually applies

CDM 2015 applies to domestic building work, but a domestic client's duties transfer automatically — to the contractor on single-contractor jobs, or to the principal contractor where there is more than one. If a domestic client makes no written appointment, the designer in control of the pre-construction phase carries the principal designer duties by default — which is why architects increasingly ask homeowners to resolve the question explicitly. On a straightforward extension the sensible answer is often that no separate appointment is needed; on a multi-contractor renovation with structural work, a deliberate appointment protects everyone. We will tell you which side of the line your project falls — before you pay for a role you may not need.

What the principal designer delivers

• Pre-construction information — the hazard and constraint pack every designer and tenderer works from.
• Design risk management — reviews and a risk register showing hazards eliminated or reduced through design, not just noted.
• Co-ordination records — evidence that designers' work was actually brought together and checked.
• Building regulations compliance records — for the 2023 role, records demonstrating how design work was planned, managed and monitored for compliance.
• The health and safety file — handed over at completion; the document future owners, and buyers' surveyors, will ask for.

Higher-risk buildings

Buildings in scope of the higher-risk regime — broadly those at least 18 metres or seven storeys high containing two or more residential units — fall under the Building Safety Regulator, with gateway approvals and substantially heavier dutyholder obligations. Principal designer appointments there demand specific, evidenced competence. If your project is in scope, say so at enquiry stage: it changes who on the panel is put forward, and we would rather scope that honestly than discover it later.

Why appoint a surveyor

The role rewards a professional who understands buildings, buildability and regulation at once — which is building surveying's home ground. Appointing the principal designer alongside our project management or contract administration service means the same panel professionals carry the design intent, the compliance duty and the site inspections, with nothing lost between separate firms.

Fees and instruction

Fixed fees scaled to project size and design complexity, agreed before appointment. Domestic clients: on most home projects the duty passes to the contractor or lead designer by default — we will tell you honestly whether you need a separate appointment at all.

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