How to appoint a Principal Designer under CDM 2015

When must a Principal Designer be appointed?

Regulation 5 requires a Principal Designer where more than one contractor is, or is reasonably foreseeable to be, working on the project at any time. Read Regulation 5 on legislation.gov.uk: client duty to appoint a designer as principal designer and a contractor as principal contractor in writing where more than one contractor is, or is reasonably foreseeable to be, working on the project, and the consequence of failing to appoint (opens in a new tab)

The client must make the appointment in writing. HSE guidance says the Principal Designer should be appointed as early as possible in the design process and, where practicable, at concept stage. HSE: are you a principal designer?: HSE guidance on principal designer appointment timing, duration, control over the pre-construction phase and capability (opens in a new tab)

Who makes the appointment?

On a commercial project, the client appoints the Principal Designer. HSE guidance for commercial clients: HSE summary of commercial client appointment and assurance responsibilities under CDM 2015 (opens in a new tab)

The client may take advice from project managers, health and safety advisers or other consultants, but responsibility for making the required appointment remains with the client. Read Regulation 5 on legislation.gov.uk: client duty to appoint a designer as principal designer and a contractor as principal contractor in writing where more than one contractor is, or is reasonably foreseeable to be, working on the project, and the consequence of failing to appoint (opens in a new tab)

Step 1: confirm whether the role is required

Start by confirming whether more than one contractor will be involved, or is reasonably foreseeable to be involved, in the project. Read Regulation 5 on legislation.gov.uk: client duty to appoint a designer as principal designer and a contractor as principal contractor in writing where more than one contractor is, or is reasonably foreseeable to be, working on the project, and the consequence of failing to appoint (opens in a new tab)

The trigger is not limited to contractors being physically on site at the same time. If the project is likely to involve more than one contractor over its course, the Principal Designer role should be planned for from the outset. The CDM duty-holder map sets out which appointments a project of that shape needs.

Step 2: identify the designer with control over the pre-construction phase

The Principal Designer must be a designer as defined by CDM and must be the designer with control over the pre-construction phase. Read Regulation 5 on legislation.gov.uk: client duty to appoint a designer as principal designer and a contractor as principal contractor in writing where more than one contractor is, or is reasonably foreseeable to be, working on the project, and the consequence of failing to appoint (opens in a new tab)

The appointment should reflect who can genuinely plan, manage, monitor and coordinate pre-construction health and safety, rather than simply assigning the role to the most senior designer or the consultant with the largest fee. HSE: are you a principal designer?: HSE guidance on principal designer appointment timing, duration, control over the pre-construction phase and capability (opens in a new tab)

Step 3: assess capability before appointment

The client should take reasonable steps to satisfy itself that the proposed Principal Designer has the skills, knowledge and experience needed for the project and, where an organisation is appointed, appropriate organisational capability. Read Regulation 8 on legislation.gov.uk: skills, knowledge and experience, and organisational capability for organisations (opens in a new tab)

Useful evidence may include:

• Experience on projects of comparable scale, complexity and risk.
• Technical knowledge relevant to the project and its design disciplines.
• Experience coordinating designers and managing design interfaces.
• Understanding of foreseeable health and safety risks arising from design decisions.
• Systems for planning, monitoring and coordinating the pre-construction phase.
• Enough resource to review design development and ongoing changes.
• Arrangements for compiling, reviewing and sharing pre-construction information.
• Relevant qualifications, CPD, professional membership or third-party assessment as supporting evidence.

No single qualification, professional membership, certificate or accreditation automatically proves suitability for a particular Principal Designer appointment. Read Regulation 8 on legislation.gov.uk: skills, knowledge and experience, and organisational capability for organisations (opens in a new tab)

Step 4: appoint early enough to influence design

Regulation 5 requires the appointment to be made as soon as practicable and, in any event, before the construction phase begins. Read Regulation 5 on legislation.gov.uk: client duty to appoint a designer as principal designer and a contractor as principal contractor in writing where more than one contractor is, or is reasonably foreseeable to be, working on the project, and the consequence of failing to appoint (opens in a new tab)

Timing matters more for the Principal Designer than simply being in place before construction begins.

The role is centred on the pre-construction phase, so a late appointment can mean important design decisions, surveys, risk-reduction opportunities and project interfaces have already been fixed before the Principal Designer has a chance to coordinate them. HSE L153 guidance: HSE guidance on CDM 2015 appointments, capability and project management arrangements (opens in a new tab)

HSE recommends appointment as early as possible in the design process and, where practicable, at concept stage. HSE: are you a principal designer?: HSE guidance on principal designer appointment timing, duration, control over the pre-construction phase and capability (opens in a new tab)

Step 5: make the appointment in writing

Regulation 5 requires the Principal Designer appointment to be in writing. Read Regulation 5 on legislation.gov.uk: client duty to appoint a designer as principal designer and a contractor as principal contractor in writing where more than one contractor is, or is reasonably foreseeable to be, working on the project, and the consequence of failing to appoint (opens in a new tab)

CDM 2015 does not prescribe a statutory Principal Designer appointment-letter template. The written appointment should make the role, appointee, project and effective date clear and should align with the actual design-management arrangements. Read Regulation 5 on legislation.gov.uk: client duty to appoint a designer as principal designer and a contractor as principal contractor in writing where more than one contractor is, or is reasonably foreseeable to be, working on the project, and the consequence of failing to appoint (opens in a new tab)

If you need a simple written record of the appointment, download our free Principal Designer Appointment Letter template.

What should a Principal Designer appointment letter cover?

CDM 2015 requires the appointment to be in writing but does not prescribe a standard form. A straightforward written appointment should make the appointment unambiguous by identifying: Read Regulation 5 on legislation.gov.uk: client duty to appoint a designer as principal designer and a contractor as principal contractor in writing where more than one contractor is, or is reasonably foreseeable to be, working on the project, and the consequence of failing to appoint (opens in a new tab)

• The client making the appointment.
• The organisation or individual appointed as Principal Designer.
• The project the appointment relates to.
• The date the appointment takes effect.
• A clear statement that the appointee is appointed as Principal Designer under the Construction (Design and Management) Regulations 2015.

The letter may also:

• Acknowledge that the Principal Designer’s statutory duties arise under CDM 2015.
• Record who signed it on behalf of the client, and in what role.
• Include an acknowledgement of receipt from the Principal Designer, if the parties want one.

Detailed services, scope, design stages, programme, interfaces and deliverables can be dealt with through the commercial appointment, contract and other project documentation where appropriate, such as the pre-construction information. They can still be included in the letter if that suits the project, but they are not needed to make a straightforward written appointment clear.

How long should the Principal Designer appointment last?

The appointment should last for as long as the Principal Designer role needs to be performed. HSE: are you a principal designer?: HSE guidance on principal designer appointment timing, duration, control over the pre-construction phase and capability (opens in a new tab)

HSE says the duration should take account of design work that continues into the construction phase and design issues that may arise during construction. HSE: are you a principal designer?: HSE guidance on principal designer appointment timing, duration, control over the pre-construction phase and capability (opens in a new tab)

If the appointment finishes before the project ends, the Principal Designer should fully brief the Principal Contractor on relevant design matters and pass the health and safety file to them. HSE guidance for principal designers: HSE summary of the principal designer role, the domestic-client position and cooperation responsibilities (opens in a new tab)

Does the appointment letter transfer the client’s duties?

No. Appointing a Principal Designer gives that designer its own statutory Principal Designer duties; it does not transfer away the commercial client’s separate duties. HSE guidance for commercial clients: HSE summary of commercial client appointment and assurance responsibilities under CDM 2015 (opens in a new tab)

The client must continue to maintain and review the project-management arrangements and take reasonable steps to ensure the Principal Designer carries out the duties specified by Regulation 4. Read Regulation 4 on legislation.gov.uk: client duty to make and maintain suitable arrangements for managing the project and to take reasonable steps to ensure the principal designer and principal contractor carry out their duties (opens in a new tab)

What information should the client provide at appointment?

The Principal Designer needs enough information to understand the project, identify gaps and coordinate the pre-construction phase effectively. HSE L153 guidance: HSE guidance on CDM 2015 appointments, capability and project management arrangements (opens in a new tab)

This may include:

• The client brief and project requirements.
• Existing pre-construction information.
• Health and safety file information where available.
• Existing surveys, drawings, service information and asset records.
• Known operational, access or site constraints.
• Programme and procurement information.
• Known design appointments and responsibilities.
• Client governance, reporting and decision-making arrangements.

How should the Principal Designer and Principal Contractor appointments align?

On a multi-contractor project, the client appoints both a Principal Designer and a Principal Contractor. Read Regulation 5 on legislation.gov.uk: client duty to appoint a designer as principal designer and a contractor as principal contractor in writing where more than one contractor is, or is reasonably foreseeable to be, working on the project, and the consequence of failing to appoint (opens in a new tab)

The appointments should create a clear route for information to move from design coordination into construction planning, with the Principal Designer and Principal Contractor able to liaise effectively as the project develops. HSE L153 guidance: HSE guidance on CDM 2015 appointments, capability and project management arrangements (opens in a new tab)

The Principal Designer may still have work to do after construction begins where design continues or changes arise, so the two appointments should not be treated as a simple handover on day one of construction. HSE: are you a principal designer?: HSE guidance on principal designer appointment timing, duration, control over the pre-construction phase and capability (opens in a new tab)

What happens if the client fails to appoint a Principal Designer?

If Regulation 5 requires a Principal Designer and the client fails to appoint one, the appointment duty does not disappear. Read Regulation 5 on legislation.gov.uk: client duty to appoint a designer as principal designer and a contractor as principal contractor in writing where more than one contractor is, or is reasonably foreseeable to be, working on the project, and the consequence of failing to appoint (opens in a new tab)

The client must itself fulfil the Principal Designer duties in Regulations 11 and 12. Read the regulations on legislation.gov.uk: Regulations 11 and 12: principal designer duties during the pre-construction phase, and the construction phase plan and health and safety file (opens in a new tab)

This is the statutory consequence of failing to appoint; it is not a substitute for making a proper appointment where one is required. Read Regulation 5 on legislation.gov.uk: client duty to appoint a designer as principal designer and a contractor as principal contractor in writing where more than one contractor is, or is reasonably foreseeable to be, working on the project, and the consequence of failing to appoint (opens in a new tab)

What about domestic clients?

Domestic-client projects have special arrangements under Regulation 7. Read Regulation 7 on legislation.gov.uk: domestic-client arrangements and transfer of specified client duties (opens in a new tab)

HSE guidance states that where a domestic client does not appoint a Principal Designer, the role must be carried out by the designer in control of the pre-construction phase. HSE guidance for principal designers: HSE summary of the principal designer role, the domestic-client position and cooperation responsibilities (opens in a new tab)

The domestic client may also make a written agreement with the Principal Designer for specified client duties in addition to the Principal Designer’s own duties. Read Regulation 7 on legislation.gov.uk: domestic-client arrangements and transfer of specified client duties (opens in a new tab)

These domestic-client arrangements should be kept separate from the commercial-client appointment process described in this guide.

Can the appointment sit inside the consultant’s professional agreement?

Yes, provided the statutory appointment is clear and in writing. Read Regulation 5 on legislation.gov.uk: client duty to appoint a designer as principal designer and a contractor as principal contractor in writing where more than one contractor is, or is reasonably foreseeable to be, working on the project, and the consequence of failing to appoint (opens in a new tab)

The CDM appointment can be included in a professional-services agreement, appointment schedule, letter or other written instrument. The important point is that the role, the appointee, the project and the effective date are unambiguous.

Can the architect automatically be Principal Designer?

No. An architect may be a suitable Principal Designer, but the title ‘architect’ does not automatically make them the Principal Designer. HSE guidance for principal designers: HSE summary of the principal designer role, the domestic-client position and cooperation responsibilities (opens in a new tab)

The client still needs to make the CDM appointment in writing and check that the proposed appointee has control over the pre-construction phase and the capability to carry out the role. Read Regulation 5 on legislation.gov.uk: client duty to appoint a designer as principal designer and a contractor as principal contractor in writing where more than one contractor is, or is reasonably foreseeable to be, working on the project, and the consequence of failing to appoint (opens in a new tab)

Is the CDM Principal Designer the same as the Building Regulations Principal Designer?

No. The CDM Principal Designer and the Principal Designer role under the Building Regulations are separate legal roles with different statutory functions.

The same organisation may sometimes be appointed to both roles, but the appointments, competence requirements and responsibilities should be considered separately. A CDM appointment should not be assumed to create a Building Regulations appointment, or vice versa.

Where the Building Regulations in England require a Principal Designer, that appointment is made under those Regulations. A client who wants the CDM Principal Designer to take on that role must appoint them for Building Regulations purposes or certify in writing that they are treated as appointed. A CDM appointment letter does not do this by itself. Building Regulations 2010, reg 11D: separate written appointment of a principal designer for the purposes of the Building Regulations, or written certification that the CDM principal designer is treated as appointed (opens in a new tab)

Can the Principal Designer appointment change during the project?

Yes. If the Principal Designer changes, the client should make the replacement appointment clearly and manage the transfer of information and coordination responsibilities.

The outgoing Principal Designer should provide relevant design information, unresolved issues, pre-construction information and health and safety file material so the new appointee can take control without losing continuity. HSE L153 guidance: HSE guidance on CDM 2015 appointments, capability and project management arrangements (opens in a new tab)

Common Principal Designer appointment mistakes

Appointing after key design decisions have already been made

The Principal Designer loses the opportunity to coordinate risk management when it can have the greatest influence.

Assuming the lead designer or architect automatically holds the role

Commercial or professional titles do not replace a clear written CDM appointment.

Choosing on qualification alone

Qualifications can support evidence of capability but do not prove suitability for the particular project.

Ignoring control over the pre-construction phase

The appointee may look suitable on paper but lack the authority to coordinate the designers whose work it is expected to manage.

Ending the appointment too early

Design work may continue into construction, leaving unresolved coordination or health and safety file responsibilities.

Using a generic appointment that does not match the project

A clear letter records who is appointed, but the professional appointment and other project documents should still reflect the stages, interfaces and information the role actually involves.

Treating the appointment as transfer of client responsibility

The commercial client’s own duties remain in place.

Confusing CDM and Building Regulations Principal Designer appointments

The same title appears in two legal regimes, but one appointment should not be assumed to satisfy the other.

Principal Designer appointment checklist

A simple one-page letter can record the written appointment; making a suitable appointment still requires the wider client checks and arrangements explained in this guide. Use this checklist for the whole appointment process:

• Confirm more than one contractor is or is reasonably foreseeable.
• Identify the designer with genuine control over the pre-construction phase.
• Assess project-specific skills, knowledge and experience.
• Assess organisational capability where an organisation is appointed.
• Check enough design-management and coordination resource is available.
• Appoint as early as possible in the design process.
• Make the appointment in writing.
• State the effective date and scope clearly.
• Provide relevant client and pre-construction information.
• Define interfaces with the client and Principal Contractor.
• Consider design work that may continue into construction.
• Plan information / health and safety file handover if the appointment may end early.
• Keep the arrangement under review if the design or project structure changes.

Example Principal Designer appointment structure

The free Aptoris template follows this simple structure on a single page. It is a practical format, not a prescribed form: CDM 2015 does not require any particular template.