Building Safety: Principal Designer and Principal Contractor

One of the changes introduced by the Building Safety Act is the new roles of Principal Designer and Principal Contractor for the purposes of building regulations. This is covered within the Building Regulations etc (Amendment) (England) Regulations 2023 (primarily Regulation 6) which supplements and amends the Building Regulations 2010.

Although these new roles are similar to those existing under the CDM Regulations, they are distinct to the CDM roles that the industry is already familiar with and each one carries specific duties:

Under the CDM regulations:

Principal Designer is focused on health and safety and pre-construction stages.

Principal Contractor is focused on health and safety of those affected by the project.

Under the building regulations and building safety legislation:

Principal Designer will focus on the design.

Principal Contractor will need to take all reasonable steps to ensure the works comply with building regulations.


Whilst the roles do not need to be carried out by four different people, whoever is appointed will need to have the requisite skill sets and it may be that separate entities will be better serve the different elements.

Importantly, clients will need to ensure that those appointed on a project, and specifically the Principal Designers and Principal Contractors, are sufficiently competent. This is one of the new client obligations the revised building regulations have introduced – along with the need for clients to submit a competence declaration when requesting a completion certificate. See Regulation 11 of the Building Regulations 2010 (as amended).

The timing of these appointments is key, with these needing to be in place at the following points:

  • in relation to higher-risk building works: before the application for building control approval is submitted to the Building Safety Regulator; and
  • in relation to all other projects: before the construction phase begins.

Where the client fails to appoint someone to the role(s) then the duties fall to the client itself.

Note that these changes apply to all building projects from 1 October 2023 subject only to some complex transitional provisions and to very limited exceptions for minor works set out in Regulation 11 and Schedule 4 of the Building Regulations 2010 (as amended

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