5th November, 2020

The Principal Designer Role, Duties And Responsibilities

CDM 2015 introduced the role of principal designer, and with this new role comes new duties and responsibilities. But who is the principal designer, and what do they do? In this post, we look at the role of the principal designer, their duties and the health and safety responsibilities under CDM.

The Principal Designer Role, Duties And Responsibilities header image

The principal designer role was introduced when the CDM regulations were updated in 2015. For the first time, a single designer needed to lead health and safety before construction work starts on site. Under CDM 2015, the principal designer has some important legal duties and responsibilities they need to carry out.

If you're not already familiar, the Construction (Design and Management) Regulations (CDM) set out legal requirements that apply to every construction project. Under CDM 2015, there are 5 CDM duty holders, who have specific legal responsibilities. The principal designer is one of those duty holders.

cdm duty holders diagram

If you have worked on construction projects before the 2015 version of CDM, you may be familiar with the principal contractor role. The principal contractor manages the construction phase and all of the contractors appointed on the project. The principal designer has a similar role but at an earlier stage of the project, managing the pre-construction phase and all of the designers appointed.

There are a few important facts to note about the principal designer role:

Who Is The Principal Designer?

CDM 2015 defines the principal designer as the designer with control over the pre-construction phase of the project. To meet this definition, the principal designer must be a designer, and also be appointed, and be in control of the pre-construction phase of the project.

The pre-construction phase is everything up to work starting on site. This is when most design and planning takes place, so it makes sense that the principal designer should lead this process. Principal designers are responsible for planning, managing and monitoring the pre-construction phase of the project. They will work with other designers, contractors and the client to consider the health and safety risks, and plan how to eliminate or control them. Appointing the principal designer early is crucial as they have several duties to perform before work starts on site.

safety planning pre-construction

The principal designer must have the right skills and experience to be able to perform the role. They should have:

The principal designer should usually be appointed in writing by the client. However, on domestic projects, the appointment may be automatic.

Principal Designer Duties

Now we know what the principal designer role is, and where they fit into the CDM team. But, the regulations are little more specific than that. The CDM regulations outline all of the duties the principal design must carry out. These principal designer duties include to:

Many duties will take place before work starts on site. Like estimating, planning and designing. But the principal designer duties don't stop when construction work starts. Their responsibilities carry on through to project completion.

Find out more about the principal designer duties in the free CDM duty holder guide for principal designers.

construction design work

Principal Designer Responsibilities

The principal designer duties outlined in the CDM regulations place quite a few health and safety responsibilities in their hands. For example, coordinating matters relating to health and safety during the pre-construction phase. That's a major part of any construction project. And perhaps the most uncertain. At this stage, the entire plan for how the work will be carried out safely needs to be decided.

The duties of the principal designer mean they are involved in:

Responsibilities for the principal designer include preparing and providing information to others. That means gathering and sharing information from the client, designers and contractors. Then giving the information to those duty holders who need it.

Principal designers should support the client with their duties. This is especially important when working with clients who are unsure of CDM. This includes assisting with the preparation and providing of the pre-construction information. Gathering existing information relating to the site and filling any gaps. The information then needs to be provided to every designer and contractor appointed. Also to those being considered for appointment. It falls on the principal designer's shoulders to make sure this information is shared. This is important information that will include site-specific hazards. It helps others plan to ensure their work and involvement in the project is carried out safely.

Principal designers need to identify, eliminating and control foreseeable risks. All designers have this duty, but the principal designer has the overall responsibility.

There can be many different designers involved in a construction project. Architects, engineers, manufacturers, suppliers, and even contractors can have an input on different parts of the design. And design work can overlap. Principal designers must also make sure that risk management is applied to all elements of the design. This means ensuring other designers comply with their CDM duties, but also that any conflict between different design elements is managed, while bringing together all the design work as a whole. When making sure designers carry out their duties, principal designers should do more than a box-ticking exercise. It should involve managing design decisions surrounding design, technical and organisational aspects.

Check if you have carried out all of your CDM responsibilities with the free CDM compliance checklist.

The principal designer will also assist the principal contractor, before work starts, in preparing the construction phase plan. They will provide all the information they hold that is relevant. This will help the principal contractor plan how work can be completed safely.

cdm principal contractor

Remember, principal designer responsibilities don't end at the pre-construction phase of the project. They have duties throughout the construction phase. They should continue to liaise with the principal contractor. And also help in the planning, management and monitoring of the construction phase.

And just because construction work starts, doesn't mean that design work stops. Design changes can be a frequent event during the project. The process of managing design risks and sharing information needs to continue to be managed by the principal designer.

The principal designer is also responsible for the preparation of the health and safety file. This should be initially drafted and the format agreed at the start of the project. It is then reviewed, updated and revised to take account of the work and any changes during the project.

At the end of the project, the principal design hands over the health and safety file to the client. Should the appointment end before completion, they must hand over the health and safety file to the principal contractor.


Need help carrying out the principal designer role under CDM? Use the free step-by-step CDM principal designer duty holder guide.

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This article was written by Emma at HASpod. Emma has over 10 years experience in health and safety and BSc (Hons) Construction Management. She is NEBOSH qualified and Tech IOSH.

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