The Principal Designer role is a legal duty, not a professional title, and the studio carries it out as an integral part of the design.
The brief
The Principal Designer role is a legal duty, not a professional title, and the studio carries it out as an integral part of the design.
Approach
Under CDM 2015, a Principal Designer must be appointed on any project involving more than one contractor, including most domestic projects. The Building Safety Act 2022 introduces a further Principal Designer role for Building Regulations compliance.
Planning and regulation
Where no appointment is made, the duties fall to the client. The studio confirms the appointment in writing and plans, manages and coordinates health and safety during the design phase.
Delivery
Pre-construction information and the health and safety file are prepared and handed over as the project progresses.
Fees
Fees are fixed for each stage and confirmed in writing once the scope is agreed. Construction cost depends on the site, the specification and the procurement route, and is established through an indicative cost plan at feasibility stage.
Common questions
Is this required for a house extension? +
If more than one contractor is involved (almost every project once you count subcontractors), CDM 2015 requires a PD to be appointed in writing. The BSA PD duty also applies to any project needing building regulations approval, which includes almost every extension.
Is it included in the full-service fee? +
Yes. On full appointments we take both PD roles as standard. No separate charge.
Can the studio act as Principal Designer on a project designed by others? +
Yes. Stand-alone PD appointments are quoted separately. We are frequently appointed on this basis where the designer does not hold the role.
What is a higher-risk building? +
Broadly, residential buildings of ≥18m or ≥7 storeys with ≥2 units. Care homes and hospitals of similar height too. These fall under the BSA gateway regime with substantially stricter duties.
What is the golden thread? +
Structured information about the building maintained through design, construction and occupation. Required on higher-risk buildings under the BSA. The PD is responsible for it through the design phase.
What if no PD is appointed? +
Under CDM 2015, duties default to the client personally. Under the BSA on higher-risk buildings, non-appointment can prevent gateway approvals. Non-appointment itself is a breach, enforceable by the HSE or BSR.
Must the Principal Designer be appointed in writing? +
Yes. Both roles require written appointment. A verbal appointment or an assumption that “the designer will handle it” does not discharge the duty.
What is a Principal Contractor? +
A separate CDM 2015 duty-holder role, normally held by the main contractor and appointed by the client for the construction phase. Both a PD and a PC must be appointed on any project with more than one contractor.
Get in touch and we will confirm what applies to the project.