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8th March, 2019

The Principal Designer Role, Duties And Responsibilities

CDM 2015 introduced the role of the principal designer. For the first time, a single designer needs to lead health and safety before work starts on site. Under CDM, 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. There are 5 CDM duty holders, the principal designer is one of those duty holders.

If you have worked on construction projects before the 2015 version of CDM, you may know the principal contractor role. The principal contractor manages the construction phase and all the contractors appointed. Similarly, the principal designer manages the pre-construction phase and all the designers appointed.

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

  • There can only be one principal designer appointed at any time
  • The principal designer is required on any project with more than one contractor
  • The principal designer is responsible for health and safety at the pre-construction phase

CDM 2015 defines the principal designer as the designer with control over 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.

cdm dutyholders
The principal designer is a CDM duty holder

Principal designers are responsible for planning, managing and monitoring the pre-construction phase of the project. Appointing the principal designer early is crucial as they have a number of duties to perform before work starts on site.

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 a number of duties the principal design must carry out. These principal designer duties include to:

  • Plan, manage and monitor the pre-construction phase
  • Coordinate matters relating to health and safety, so that the project can be carried out without risks to health or safety
  • Consider health and safety when design, technical and organisational aspects are being decided
  • Consider health and safety when planning the various items or stages of work
  • Consider health and safety when estimating the time required to complete work or stages
  • Take into account the general principles of prevention and contents of any construction phase plan or health and safety file
  • Identify and eliminate or control foreseeable risks to the health or safety of any person affected by the construction work
  • Identify and eliminate or control foreseeable risks to the health or safety in future use, maintenance or cleaning
  • Ensure designers comply with CDM duties
  • Ensure everyone working on the pre-construction phase cooperate with each other
  • Assist the client in the provision of the pre-construction information
  • Provide pre-construction information to every designer and contractor appointed, or being considered
  • Liaise with the principal contractor
  • Share information relevant to planning, managing and monitoring of the construction phase
  • Prepare a health and safety file, and ensure it is appropriately reviewed, updated and revised due to any changes that have occurred

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.

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:

  • Advising the client
  • Assisting with client duties
  • Design health and safety decisions
  • Construction health and safety decisions
  • Managing designers and ensuring they comply
  • Cooperating with the principal contractor
  • Providing health and safety information

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 give the information to those duty holders who need it.

They should assist 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 contractor has the overall responsibility.

principal designer risks
Principal designers identify health and safety risks during design

Principal designers need to identify and eliminate or control expected risks in their own design. They must also make sure this risk management is applied to all elements of the design. Including design work carried out by others.

This means ensuring other designers comply with their CDM duties. 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.

The principal designer will 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 safely completed.

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.

Just because work starts on site, doesn't mean design work stops either. 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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