Who is a Principal Designer?

“A Principal Designer is an individual or an organisation appointed by the client to manage design health and safety issues on a construction project.”

• “The role of Principal Designer is a legal requirement under Construction (Design and Management) Regulations 2015 (CDM Regulations) for any construction work carried out in the UK that involves more than one contractor.”.


• The term 'Principal Designer' can be misleading and may easily be mistaken with a 'Lead Designer' or a Lead Architect. A Principal Designer under CDM Regulations is responsible for health and safety aspects of the project design and is not responsible for any architectural, engineering, or technical design considerations.


• The role of Principal Designer starts from very early stages of the design (i.e. from concept design) through planning and detailed design and usually extends right up to the completion of construction works on site.


• The Principal Designer role under CDM Regulations is important in terms of identifying and managing health and safety risk in the design which could potentially cause issues during construction phase and more critically during post construction operation and maintenance phase.


• The Principal Designer is not a completely new role starting in 2015. Since the inception of the CDM Regulations back in 1994, roles with broadly similar sort of duties, albeit with different names have existed and have been applicable to the construction projects. The Planning Supervisor role existed from 1994/95 and then it changed to CDM Co-ordinator in 2007 which remained applicable before being replaced by the Principal Designer in 2015. However, the Principal Designer role is more stringent in terms of its legal liability and is more involved compared to its two predecessors. For a brief background and history of the Principal Designer Role please follow the section History and Background of Principal Designer Role.

Find out more about the Principal Designer Role and Responsibilities in the sections below or select from the contents list on the left.

When is a principal designer required?

A Principal Designer is required to be appointed on every construction work in the UK which involves more than one contractor on site.

Importance of Principal Designer Role?

A Principal Designer is responsible for design health and safety matters on a construction project and is involved in the project from an early stage i.e. from the conceptual design stage to the completion of works on site. The early design decisions have a significant impact on accidents on construction site and also in a completed building. Principal Designer's liaise with the Principal Contractor ensures that potential construction health and safety risks are property identified and managed on site. Principal Designer role also influences the post completion health and safety risks (i.e. in regular maintenance, repair, cleaning and use of the completed property as a workplace). Principal Designer role performed effectively ensures a safe construction site and a safe building to use, operate, manage and maintain, once completed on site.

What a Principal Designer does?

As mentioned above, a Principal Designer is responsible for co-ordination of design health and safety aspects on a construction project, essentially making sure that project design is safe before construction work commences on site. It is a legal role and requirement under the CDM Regulations 2015.

What are the duties of a principal designer?

Regulation 11 and 12 of the CDM Regulations 2015 list the duties of the Principal Designer on a project and they are as follows:

• Plan, manage and monitor the Pre-construction Phase (Regulation 11(1))
• Co-ordinate matters relating to health and safety during Pre-construction Phase taking into account General Principles of Prevention, contents of any Construction Phase Plan and Health and Safety File ‐ in particular during planning and developing project timescales (Regulation 11(2))
• Identify, eliminate or control, so far as is reasonably practicable, (in planning, managing and monitoring the Pre-construction Phase) foreseeable health and safety risks during construction, maintenance, cleaning and use as a workplace (Regulation 11(3))
• Ensure all Designers comply with their duties (Regulation 11(4))
• Ensure all involved in Pre-construction Phase co-ordinate and co-operate with each other (Regulation 11(5))
• Prepare Pre-construction Information (Regulation 11(6)a))
• Provide Pre-construction Information to every designer and contractor (appointed or prospective) (Regulation 11(6)b))
• For the duration of Principal Designer appointment, liaise with Principal Contractor and share information about construction phase and co-ordination of health and safety matters (Regulation 11(7))
• Provide Pre-construction Information and any information received from the Designers to the Principal Contractor Regulation 12(3))
• Prepare a Health and Safety File during the Pre-construction Phase and review, update and revise regularly (Regulation 12(5 and 6))
• Pass on the draft Health and Safety File to the Principal Contractor , if Principal Designer appointment finishes before the project completion (Regulation 12(8))

Explanation of Principal Designer Duties

The above legal duties of a Principal Designer are briefly explained as follows:

Plan, manage and monitor the Pre-construction Phase (Regulation 11(1))

There is similar responsibility for a Principal Contractor to plan, manage and monitor the construction phase. Principal Designer should assist the client and other members of the project team in compliance with the CDM Regulations in the pre-construction Phase. Principal Designer should understand client's brief and expectations of the project and map out (plan) the pre-construction phase design process to ensure that health and safety aspects of each design elements are discussed and dealt with. This process has to be managed for the whole duration of the pre-construction phase and monitored to ensure that it is working effectively.

Co-ordinate matters relating to health and safety during Pre-construction Phase taking into account General Principles of Prevention, contents of any Construction Phase Plan and Health and Safety File ‐ in particular during planning and developing project timescales (Regulation 11(2)).

This is a key responsibility for the Principal Designer role. Client and designers have their own CDM duties to fulfil. Any particular design aspect of one designer can have health and safety implications on other designers ' design. Therefore, it is a Principal Designer's duty to ensure design health and safety matters are co-ordinated within the project team (including client and designers and other consultants). Co-ordination could happen through regular design team meetings and workshops etc.

Identify, eliminate or control, so far as is reasonably practicable, (in planning, managing and monitoring the Pre-construction Phase foreseeable health and safety risks during construction, maintenance, cleaning and use as a workplace (Regulation 11(3)).

This is without a doubt the most onerous responsibility imposed on a Principal Designer. In addition to co-ordinating health and safety matters during the pre-construction phase, a Principal Designer must review and analyse health and safety risks arising from the existing site conditions, different technical designs (architectural, structural, civil, electrical, mechanical, public health, fire safety, landscape, any specialist contractor design (i.e. swimming pools etc) and impact of these health and safety risks on construction phase and post completion phase (i.e. maintenance and repair and use of the property as a workplace, if applicable). The effort has to be made by the Principal Designer, in assistance with the client and designers to eliminate the identified risks. Where elimination is not possible, there should be a strategy and solution in place to mitigate, manage and control the impact for these risks.

Ensure all Designers comply with their duties (Regulation 11(4))

Designers have their own specified CDM Designer Duties. However, CDM Regulations put a responsibility also on Principal Designer to ensure that the project designers are fulfilling their duties. First of all, designers should be made aware of their duties, in a case if any designer is not fully update to speed with the CDM Regulations and then providing them help and assistance to fulfil their duties. The help and assistance could come in a form of best practice guidance, worked out examples, templates and breakdown of their responsibilities. Outcome of this could be good and effective Designer Risk Assessments (DRA) produced by the project designers. Please refer to our CDM Designer Duties page for more details on this.

Ensure all involved in pre-construction Phase co-ordinate and co-operate with each other (Regulation 11(5))

This requirement is similar to the one above for co-ordination of health and safety matters during the pre-construction phase. However, the emphasis here is to ensure that all who are involved in the pre-construction phase (client, project manager, different designers, consultants etc) are communicating with each other and health and safety matters are being dealt with in co-ordination and co-operation with each other, avoiding a typical over the wall syndrome in construction industry.

Prepare Pre-construction Information (Regulation 11(6)a))

Please see section Pre-construction Information (PCI).

Provide Pre-construction Information (PCI) to every designer and contractor (appointed or prospective) (Regulation 11(6)b))

As mentioned above, the Pre-construction Information (PCI) is to be provided by the Principal Designer to all appointed designers and Principal Contractor. The Pre-construction Information (PCI) must also be provided to all those designers and contractors who are bidding for the work.

For the duration of Principal Designer appointment, liaise with Principal Contractor and share information about construction phase and co-ordination of health and safety matters (Regulation 11(7))

The Principal Designer is also required to liaise with the appointed Principal Contractor. The Principal Designer has to pass on the Pre-construction Information (PCI) and other information relevant to health and safety matters in particular to construction phase of the project. This then enables the Principal Contractor to develop an effective Construction Phase Plan (CPP) and put other preventive and protective measures in place on site to manage and mitigate the identified health and safety risks during the construction phase.

Provide Pre-construction Information (PCI) and any information received from the Designers to the Principal Contractor (Regulation 12(3))

As described above, it is a duty of Principal Designer to pass on the Pre-construction Information (PCI) to the appointed Principal Contractor . In addition, there could be other information produced by the designers (e.g. Designer Risk Assessments (DRAs), Reports and any further information designers have received from the client etc). Such information as received by the Principal Designer must also be passed on to the Principal Contractor as soon as possible.

Prepare a Health and Safety File during the Pre-construction Phase and review, update and revise regularly (Regulation 12(5 and 6))

Please see section Health and Safety File.

Pass on the draft Health and Safety File to the Principal Contractor, if Principal Designer appointment finishes before the project completion (Regulation 12(8))

In those situations where the Principal Designer is appointed for a limited duration on the project and their role does not extend to the completion of site works, then the Principal Designer is required to pass on the incomplete or draft Health and Safety File to Principal Contractor for completion and handing over to the client on completion of site works.

What is the legal requirement for Principal Designer appointment?

Regulation 5(1) of the Construction (Design and Management) Regulations 2015 (CDM Regulations) place the legal requirement on the client of a construction project to make the appointment of a Principal Designer in a formal manner (i.e. in writing). Therefore, it is a statutory role and places a criminal liability on its appointee and its holder.

Who appoints a Principal Designer?

As mentioned above in the question "What is the legal requirements for Principal Designer appointment? " it is the legal requirement on the client of a construction project to make the appointment of a Principal Designer in writing. However, in practical terms the appointment can be made by anyone involved in the project i.e., the Project Manager, Architect or even a Design and Build Contractor (if they are involved early enough in the project) etc as long as the client is aware that such appointment has been made in writing.

Can anyone else make the appointment of a Principal Designer instead of the client?

As mentioned in the above question, although it is a client requirement to appoint a Principal Designer in writing, however, in practical terms anyone involved in the project i.e., the Project Manager, Architect or even a Design and Build Contractor (if they are involved early enough in the project) etc can appoint the Principal Designer as long as the client is aware of that appointment and that the appointment has been made in writing.

Who can be a Principal Designer?

Any person or an organisation who holds necessary and relevant skills, knowledge, experience, and organisational capability can act as CDM Principal Designer. The CDM Regulations require that a Principal Designer must be a designers by profession. There is a reason for this requirement. As mentioned above, Principal Designer is mainly concerned with health and safety aspects of a building design and without understanding of the construction project design the role cannot be fulfilled effectively.

What (competence) skills, qualifications, knowledge, experience (SKE), and organisational capability are required by a Principal Designer?

To fulfil the role and Principal Designer responsibilities, the following skills, knowledge, experience, and organisational capability are required.

1. The CDM Regulations require that a Principal Designer must be a designers by profession.
2. Understanding, knowledge and experience of identifying risks from the existing site conditions, commissioned surveys and reports etc.
3. Understanding, knowledge and experience of architectural, structural, civil, mechanical, electrical and other relevant design disciplines.
4. Understanding, knowledge and experience of health and safety legislation and legal requirements (theoretical and practical) and its application in the construction industry.
5. Understanding, knowledge and experience of construction site operations.
6. Understanding, knowledge and experience of project and facilities management, post site completion maintenance, repair and use.
7. Good soft skills e.g. communication skills, team management and project management etc.
8. If an organisation, the necessary arrangements and competent resources in place to project manage a number of Principal Designer appointments running concurrently.

As obvious from the above, CDM Principal Designer is a very involved role and will require a well-rounded understanding, knowledge and experience of different building design disciplines, health and safety, construction site operations and building maintenance and repair etc.

Who could become a Principal Designer, an individual or an organisation?

The CDM Regulations 2015 allow both an individual or an organisation to act as the Principal Designer as long as they as competent relevant to project size, nature and the complexity, in other terms the requirements of skills, knowledge, experience and the organisation capability (where applicable) are met.

Can there be more than one Principal Designers on a project?

No, under the CDM Regulations 2015 there can only be one Principal Designer on a construction project at any one time. However, it does not have to be the same Principal Designer for the whole duration of the project. For example, one Principal Designer may be involved from early concept stage until the completion of pre-construction stage and a new Principal Designer may take over for the construction phase to project completion on site.

When should principal designers be appointed?

The appointment should be made as soon as possible, ideally during the concept design of a construction project (or RIBA Plan of Work 2020 ‐ Stage 2). The Principal Designer role mainly concerns with design health and safety issues and therefore early appointment is required to make the appointment effective and useful for the project.

What is the purpose of a Principal Designer?

Construction projects by its very nature are hazardous. Construction activity is mostly carried out in an uncontrolled, transient production area, often restricted, fully or partly occupied and weather exposed, constructing to a bespoke design and in a constantly changing environment (in a flux) for the duration of site works. Historically, main contractor and sub-contractors are thought to be solely responsible for any accidents on a construction site. This goes all the way back to the Code of Hammurabi (c 1755 ‐ 1750 BC) which declared that "if a builder builds a house for someone, and does not construct it properly, and the house which he built falls in and kills its owner, then that builder shall be put to death" (229). However, it is not always the contractors who are at fault. Previous research work and a 2003 report by Health and Safety Executive (HSE) found that up to 50% of accidents could be mitigated through a safer design. This is where the legal role of a Principal Designer comes into play. In simplistic terms, a Principal Designer must ensure that design of a construction project is safe before it is constructed on site.

History and background of Principal Designer role?

Construction (Design and Management) Regulations 2015 (CDM Regulations) first came into force in the UK in 1995 albeit Regulations were called CDM Regulations 1994. As the name of the Regulations suggests, the Regulations spilt a construction project into two phases. Construction Design or Pre-construction Phase and a Construction Management or simply Construction Phase. The Regulations are based on the premise that for each of these two phases of a construction project there should be someone responsible for health and safety, hence two new legal roles were introduced in the first version of CDM Regulations 1994. First role was of Planning Supervisor ‐ responsible for co-ordination of health and safety in Pre-construction Phase and the second role of a Principal Contractor ‐ responsible for health and safety in Construction Phase. In the 2007 revision of CDM Regulations, the Planning Supervisor role was replaced with a CDM Co-ordinator and in the latest 2015 version of the CDM Regulations the role of CDM Co-ordinator has been replaced with a Principal Designer. The Principal Contractor role title has stayed the same since CDM Regulations 1994. Even though the title for person or an organisation responsible for health and safety in pre-construction phase has changed from a Planning Supervisor, then CDM Co-ordinator and now to a Principal Designer the essence of their duties has remained unchanged.

What will happen if a Principal Designer is not appointed?

As mentioned above, it is a legal requirement on the client of a construction project that they appoint a Principal Designer as soon as possible. If this appointment is not made by the client, then the CDM Regulations take it by default, that the client (of a non-domestic construction project) themselves have taken the role and responsibilities of a Principal Designer for the project. In case of a domestic client the roles and responsibilities of a Principal Designer default to the lead designer of the project when client fails to make such appointment.

Other CDM Guidance

In addition to this, we at (Safescope) have also produced a number of other in-depth CDM Guides on various related topics. These guides are available on this website. Please follow the Link.

Need help?

We (Safescope) specialise in CDM and Construction Health and Safety and provide proactive yet cost effective CDM Principal Designer, Client CDM Advisor, Principal Contractor CDM Advisor roles and various CDM Training Courses. Please get in contact for an informal chat or a hassle free prompt fee proposal.

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