A Simple Guide to the Principal Designer Role in 2021

The position of principal designer (PD) was created by the changes to the CDM Regulations in 2015.

For the first time, a single designer needed to lead health and safety before construction work starts on site.

Although this was six years ago, we often meet people who are unsure of the role of a principal designer.

This guide, will help anyone understand the basics of what a PD does and his responsibilities.

We will cover some of the roles and responsibilities of a PD and look at what they do and their function in construction projects.

You will be able to see some of the reasons why they should be appointed and engaged at the very start of the design stage of a project.

OK with that established, let’s make a start.

What Is a Principal Designer?

There are 5 duty holders under CDM 2015 and a principal designer is one of them.

The principal designer is responsible for the health & safety at the pre-construction phase and one must be appointed if there is more than one contractor on site.

Principal designers are responsible for planning, monitoring and managing the pre-construction phase (until work on-site begins).

They also have to be a catalyst, coordinator and communicator since they must convey ALL information to the following;

    • The client
    • The principal contractor and sub-contractors
    • Any other designers (including architects and engineers)

Appointing the principal designer early is crucial as they have several duties to perform before work starts on site. Failure to do this often costs time and money further down the line.

Ok, the next logical thought most people have is……………………

Does My Project Need a Principal Designer?

The short answer is yes!

Whilst the principal contractor or even the client himself can be deemed to be the principal designer, the person appointed must have the necessary skills knowledge and experience.

(Defined as SKE under the 2015 regulations)

Please note SKE is being updated to SKATE ( skills, knowledge, attitude, training and experience as per latest HCLG thinking)

The CDM regulations state that a PD is required on any project with more than one contractor on site (this includes sub-contractors).            

The principal designer must be appointed by the client, as soon as it is established that more than one contractor is or is likely to be, working on site.

From outset the principal designer needs to plan, manage, monitor and control the design stages.

So far, we know what a principal designer is and when and if we need one but who can be one?

right way

Who Can Be a Principal Designer?

What qualifies a person to be a principal designer?

Principal designers must satisfy three minimum elements:

  1. They must be in control of the pre-construction phase.
  2. They must have the necessary skills knowledge, experience, attitude and training (SKATE).
  3. They must have the criteria of being a designer.

It is also permissible for the client themselves to be the principal designer but for various reasons they often choose not to do this.

Indeed, if the client fails to appoint a principal designer or decide not to appoint one, they are automatically deemed to have inherited the role, with ALL of the duties and responsibilities that entails.

Principal Designer

Whatever the case, they must have the necessary experience, skills, knowledge, attitude and training (SKATE) to carry out all the principal design duties functions and roles and have the organisational capacity to do so.

In the case of a domestic client, he or she is unlikely to have knowledge of the requirement of a principal designer so this role  automatically defaults to the person deemed ‘in control’ usually the designing architect or technician.

So What Does A Principal Designer Do Exactly?

To include every role and responsibility is beyond the scope of this article but we have listed some of the most important roles and duties below.

  • First and foremost, he has to prepare the H&S file for the pre-construction phase. Nothing happens on site before this.
  • Secondly, that file has to be revised if there are any changes to the design. For a complete and detailed list of the roles and responsibilities of a principal designer follow this link to view the relevant 2015 CDM Regulations
  • The principal designer has to plan, manage, monitor, coordinate and communicate all of the H&S  information for the pre-construction phase to all the relevant parties.

It does not stop there though!

  • CDM 2015 is very COLLABORATIVE. Project teams stand or fall together on compliance.
  • Build the right team and communicate effectively throughout the project, working to the common goal of project success for all for ever. Build on experience. Individual experience, Team experience. Corporate experience.
  • The above applies to design changes, technical changes and time estimations for the work carried out.
  • He must eliminate or reduce the risks now and in the future operation of the building.


  • To sum up, a principal designer is the catalyst & coordinator in a triangular relationship between him and the principal contractor and the client.
  • Early appointment on a project is crucial to save money and time and to keep a project on track and make sure everyone receives the relevant information.
  • Early appointment ensures good communication to all the relevant parties, design changes noted and amendments made which can save both time and money on project costs.
  • A principal designer aims to ‘measure twice and cut once’ – a key to avoiding costly mistakes.

If you have any questions about principal design you can call Andrew Warring on 01792 797833 who will be happy to chat with you.