What Is a Principal Designer? CDM 2015 Duties Explained
The Principal Designer is the dutyholder who manages health and safety during the design phase of a construction project. Here is when you need one and why it matters.
A Principal Designer is the dutyholder who plans, manages and coordinates health and safety during the pre-construction phase of a construction project. In plain terms, they deal with risk while it is still a line on a drawing, before anyone sets foot on site. The role sits under the Construction (Design and Management) Regulations 2015 (CDM), and the duty to appoint one falls on you, the client.
That last point catches people out. So let us walk through it.
When you must appoint a Principal Designer
Under CDM 2015, you must appoint a Principal Designer on any project with more than one contractor. That covers almost every commercial project and a good number of domestic ones. The appointment has to be in writing, made before the construction phase begins, and ideally at the very start of design.
Miss that step and the role does not vanish. The duty simply transfers to you. The client takes on the Principal Designer role and every duty that comes with it, by default. Exposure runs from enforcement action and project delays through to unlimited fines.
What the dutyholder actually does
A Principal Designer is not a job title you hand out and forget. The role carries real, ongoing duties through the design phase:
- Gathering and issuing the pre-construction information to the design team and the Principal Contractor.
- Submitting the F10 notification to the HSE on notifiable projects, correctly and on time.
- Designing risk out early, eliminating or reducing hazards at the drawing-board stage rather than leaving them for the build.
- Coordinating designers and keeping a record of who decided what.
- Compiling the health and safety file that follows the building through its life.
The thread running through all of it is the same. Decisions made on paper are cheaper, safer and easier to change than decisions made in concrete.
Two roles, one name: CDM versus the Building Safety Act
Here is the part that causes the most confusion. There are now two Principal Designer roles. They share a name but not a job.
The CDM Principal Designer manages health and safety during design, as above. The Building Safety Act 2022 Principal Designer is a separate legal role: it plans and coordinates design so the finished building complies with the Building Regulations.
Different law, different focus, different duty. Appointing one does not cover the other. A project with more than one designer or contractor can need both. So check which role you are actually filling before you assume a single appointment has you covered.
Principal Designer versus Principal Contractor
A second common mix-up. The Principal Designer and the Principal Contractor are two different dutyholders, not two names for the same person.
The Principal Designer owns health and safety during design. The Principal Contractor owns it during the build. Most projects need both, appointed separately and in writing. One does not absorb the other.
Getting it right from the start
The Principal Designer duty is one of the few things in construction compliance that lands on the client whether you act on it or not. Appointing a competent dutyholder early is the straightforward way to discharge it, and to keep the project moving.
Spectra acts as the appointed Principal Designer under both CDM 2015 and the Building Safety Act 2022, led by a named consultant with 25+ years' construction experience and backed by APS (Association of Project Safety) Corporate Membership. We can carry the full duty or work alongside an in-house team that wants support rather than a full appointment.
If you are not certain whether your project needs a Principal Designer, or who currently holds the role, book a free CDM review. We will tell you plainly where you stand and what, if anything, you need to put right.