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Principal Designer Series: The role of the Principal Designer – Building Safety Act v CDM Regulations

August 2023
Andrew Croft and Felicity Hird

As we witness an increase in Building Safety Act drafting across the industry, one question is cropping up more and more frequently – how is the new role of the Principal Designer under the Building Safety Act distinct from the role of the Principal Designer under the CDM Regulations?

What are we seeing?

It is becoming common place for appointments to include an obligation that a consultant will assume the role of the Principal Designer under the Building Safety Act. However, the fact remains that little is known about this role as the detail of the role will be set out in secondary legislation yet to be handed down by parliament. This is particularly important as an organisation or individual will have to satisfy itself and confirm to the client that it is competent to carry out this new role. The advice therefore, if you are negotiating with a client who requires you to perform the role of the Principal Designer under the Building Safety Act is to resist in the first instance, on the basis that until sufficiently detailed secondary legislation is handed down, there is not enough certainty around the requirements of the role to be able to accept the obligation. If met with resistance, the best position should be to ensure acceptance of the role is subject to further agreement of the precise scope of the role, and an additional fee.

What do we know about the role?

With little information in the public domain, it is difficult to gain clarity on the extent to which the two roles will differ from one another. It is likely that the roles will be carried out by the same organisation or individual, given the overlap in responsibilities. However, the HSE (the Building Safety Regulator) has indicated that it expects the Principal Designer under the Building Safety Act to have a ‘lead’ role in the design. Interestingly, draft legislation published last year[1] (now withdrawn) provided that a client could simply ‘certify in writing’ that the Principal Designer under the CDM Regulations will also take on the new role of the Principal Designer under the Act.

The distinct requirements of the Principal Designer under the Building Safety Act will likely be linked to new requirements of the Act. It is believed that the Principal Designer will be responsible for the preparation of the Building Safety Information Pack and Fire Safety Plan for issue to the Regulator through the client. The Principal Designer will also be responsible for the issuing of a conformity statement to the Regulator, which will confirm that to the best of the consultant’s knowledge the building complies with building regulations.

The draft legislation published last year provides insight into what the Principal Designer role may look like. Similar to the role under the CDM Regulations, the draft legislation positioned the role of the Principal Designer predominantly in the pre-construction phase with an obligation to plan, manage and monitor the design work. The draft legislation however placed a greater emphasis on the duty of the Principal Designer to ensure building regulation compliance.

Possible risks

The draft legislation also included some key risks. The Principal Designer was required to ‘coordinate the work of all designers’ so that if built, the design would achieve building regulation compliance. This introduces the possibility that the Principal Designer may indirectly become responsible for the work of other designers on the project and introduces liability for design outside of its immediate control. Equally, designers were under an obligation to consider the work of other designers and report any concerns as to building regulation compliance to the Principal Designer, which creates the risk that the Principal Designer role includes a ‘design audit’ responsibility.

There is a great deal more to learn about the precise requirements of this role as legislation is gradually handed down by parliament. Stay tuned for further updates in this series as we unpack the role of the Principal Designer.

If you have any queries, please contact Andrew Croft (, 020 7469 0412) or Felicity Hird (

[1] The Building (Appointment of Persons, Industry Competence and Dutyholders) Regulations 2021

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