CDM duty holders explained

The main duty holders are clients, designers, Principal Designers, Principal Contractors and contractors. Workers also have duties under CDM 2015, although they are not normally grouped with the five project-management duty holder roles in the same way. Understanding who is responsible for what is important because CDM is designed around cooperation: no single role can manage every project risk alone. HSE guidance: summary of duties under CDM 2015 (opens in a new tab)

What is a CDM duty holder?

A duty holder is a person or organisation that has specific legal responsibilities under the Construction (Design and Management) Regulations 2015. The duties arise because that role has control or influence over part of a construction project.

HSE makes clear that virtually everyone involved in a construction project has legal duties under CDM 2015. The duties are different depending on whether someone commissions the work, designs it, coordinates design, manages the construction phase, carries out construction work or works on site. HSE guidance: what do I need to do? Definitions of duty holders (opens in a new tab)

Who are the main CDM duty holders?

The main CDM duty holders are:

• Client
• Designer
• Principal Designer
• Principal Contractor
• Contractor

Workers also have direct duties under CDM 2015, including cooperating with employers and other duty holders, using equipment and controls correctly, and reporting matters that may endanger health and safety. HSE guidance: summary of duties under CDM 2015 (opens in a new tab)

The Client

The client is the person or organisation for whom a construction project is carried out. Commercial clients have the client duties in full. Domestic clients are also within the scope of CDM 2015, but their client duties normally pass to another duty holder. HSE guidance: commercial clients (opens in a new tab)

A commercial client has significant influence over how a project is set up. Their main responsibilities include making suitable arrangements for managing the project, appointing the right duty holders where required, allowing sufficient time and resources, providing relevant pre-construction information and taking reasonable steps to make sure the Principal Designer and Principal Contractor are carrying out their duties.

Where a project involves more than one contractor, the client must appoint a Principal Designer and a Principal Contractor in writing.

The Designer

A designer is any person or organisation that prepares or modifies a design as part of a business. This can include architects and engineers, but also quantity surveyors, specialist contractors, manufacturers and tradespeople where they make design decisions. HSE guidance: what do I need to do? Definitions of duty holders (opens in a new tab)

Designers must eliminate foreseeable risks so far as is reasonably practicable and, where risks cannot be eliminated, reduce or control them. They also need to provide relevant information to other members of the project team so that risks can be managed during construction, use and maintenance.

A contractor can also be a designer if it designs part of the work it installs. In that situation, both sets of duties may apply to the same organisation.

The Principal Designer

The Principal Designer is the designer appointed by the client on a project involving more than one contractor. The role is focused on the pre-construction phase and on coordinating health and safety matters arising from design. HSE guidance: principal designers (opens in a new tab)

The Principal Designer plans, manages, monitors and coordinates the pre-construction phase. This includes helping to identify, eliminate or control foreseeable risks, making sure designers cooperate and fulfil their duties, and ensuring relevant information is prepared and shared.

The Principal Designer must also liaise with the Principal Contractor so that information and risks identified during design are understood as the project moves into construction.

The Principal Contractor

The Principal Contractor is the contractor appointed by the client to manage and coordinate the construction phase on a project involving more than one contractor. HSE guidance: principal contractors (opens in a new tab)

The Principal Contractor plans, manages, monitors and coordinates the construction phase. Key responsibilities include preparing and maintaining the construction phase plan, coordinating contractors, organising cooperation, providing suitable site inductions, consulting workers, preventing unauthorised access and making sure suitable welfare facilities are available.

The Principal Contractor does not remove the duties of the individual contractors working on the project. Each contractor remains responsible for the work and people under its own control.

The Contractor

A contractor is a person or business that carries out, manages or controls construction work. Contractors include main contractors, subcontractors, specialist trades, sole traders and self-employed people who control construction work. HSE guidance: contractors, roles and responsibilities (opens in a new tab)

Contractors must plan, manage and monitor the work under their control so it is carried out without risks to health and safety so far as is reasonably practicable. They must use people with suitable skills, knowledge, training and experience, provide appropriate supervision and information, cooperate with other duty holders, and comply with relevant parts of the construction phase plan.

Where there is only one contractor on a project, that contractor must prepare or arrange the construction phase plan before the construction site is set up.

What duties do workers have under CDM?

Workers are the people who actually carry out construction work. HSE includes tradespeople, labourers and supervisors such as foremen and chargehands within this group. HSE guidance: what do I need to do? Definitions of duty holders (opens in a new tab)

Workers must cooperate with their employer and other duty holders, follow the arrangements and controls put in place for the work, and report anything they see that may endanger their own health and safety or that of others. They must also be consulted on matters affecting their health, safety and welfare.

Worker duties do not replace the management duties held by clients, designers and contractors. They sit alongside them.

How do the CDM duty holders fit together?

CDM works as a chain of responsibility across the project lifecycle rather than as a series of isolated roles.

• The client sets the project up and creates the conditions for effective management.
• Designers make decisions that can eliminate or reduce risk before work reaches site.
• The Principal Designer coordinates health and safety during the pre-construction phase.
• The Principal Contractor coordinates health and safety during the construction phase.
• Contractors plan and control the work they carry out.
• Workers follow the arrangements and contribute practical knowledge about how work can be carried out safely.

The roles overlap deliberately. For example, the Principal Designer needs information from designers and the client, while the Principal Contractor needs design and pre-construction information to plan the construction phase. Contractors then need clear coordination and information so individual work packages can be delivered safely. HSE guidance: summary of duties under CDM 2015 (opens in a new tab)

When are Principal Designer and Principal Contractor appointments required?

A Principal Designer and Principal Contractor are required when a construction project involves, or is reasonably foreseeable to involve, more than one contractor. The client is responsible for making those appointments in writing. HSE guidance: summary of the legal requirements of CDM 2015 (opens in a new tab)

The trigger is the involvement of more than one contractor, not project value, project duration or whether the project is notifiable to HSE. A relatively small project can therefore require both principal duty holder appointments.

On a single-contractor project there is no Principal Designer or Principal Contractor appointment under CDM 2015. The client and contractor duties still apply, and designers still have their own duties where design work is undertaken.

Can one organisation hold more than one CDM role?

Yes. CDM 2015 does not require every duty holder role to be performed by a different organisation. An organisation may hold more than one role if it meets the requirements of each role and has the necessary skills, knowledge, experience and organisational capability.

Examples might include a design-and-build contractor acting as both designer and contractor, or an organisation appointed as Principal Designer while also carrying out design work. Holding more than one role does not cancel or merge the duties: the organisation needs to discharge each set of responsibilities.

Where roles overlap, appointments and responsibilities should be clear so that important tasks do not fall between organisations or become duplicated without coordination.

What happens on domestic projects?

Domestic clients are people having construction work carried out on their own home, or the home of a family member, where the work is not part of a business. CDM 2015 still applies, but the domestic client duties normally transfer to another duty holder. HSE guidance: domestic clients (opens in a new tab)

On a single-contractor domestic project, the client duties normally pass to the contractor. On a project with more than one contractor, they normally pass to the Principal Contractor. The domestic client can instead enter into a written agreement with the Principal Designer for the Principal Designer to carry out the client duties. HSE guidance: summary of duties under CDM 2015 (opens in a new tab)

The other duty holders continue to have their normal CDM responsibilities regardless of the way the domestic client duties are allocated.

CDM duty holders and competence

Appointments under CDM should not be treated as a naming exercise. A person or organisation taking on a duty holder role needs the capability to carry it out properly.

CDM 2015 requires those appointing designers and contractors to take reasonable steps to satisfy themselves that the person or organisation has the skills, knowledge and experience, and where the duty holder is an organisation, the organisational capability necessary to fulfil the role in a way that secures health and safety. Read Regulation 8 on legislation.gov.uk: general duties (opens in a new tab)

For senior coordination roles such as Principal Designer and Principal Contractor, this means considering the complexity of the project, the risks involved and whether the organisation has suitable systems, resources and people — not simply checking certificates or job titles.

Common CDM duty holder mistakes

Assuming appointing someone transfers all responsibility

Appointments allocate roles, but they do not remove the appointing client’s own duties. Each duty holder remains responsible for the duties placed on them.

Confusing project job titles with CDM roles

A project manager, architect or site manager is not automatically a particular CDM duty holder simply because of their job title. Look at the legal role and the work actually being carried out.

Failing to make principal appointments early enough

Where more than one contractor is involved, the Principal Designer and Principal Contractor appointments need to be made at the appropriate time so they can influence planning and delivery.

Treating the Principal Contractor as responsible for every contractor duty

The Principal Contractor coordinates the construction phase, but individual contractors keep direct responsibility for the work and workers they control.

Treating the Principal Designer as responsible for every design decision

The Principal Designer coordinates the pre-construction phase, but each designer keeps their own Regulation 9 duties for the designs they prepare or modify.

Letting interfaces between roles go unmanaged

Many project risks arise between packages, phases and organisations. Cooperation and information-sharing are essential parts of the CDM structure.

CDM duty holder responsibilities at a glance

CDM duty holder checklist

A practical project-level check should ask whether:

• the client has been identified and understands the arrangements they need to put in place
• the project has been assessed to determine whether more than one contractor will be involved
• the Principal Designer and Principal Contractor have been appointed in writing where required
• designers and contractors have been checked for suitable capability before appointment
• roles, responsibilities and interfaces are clear to the project team
• relevant pre-construction information has been prepared and shared
• designers are coordinating foreseeable risks through the design process
• the Principal Designer is coordinating the pre-construction phase where required
• the Principal Contractor is coordinating the construction phase where required
• contractors understand the work and risks under their control
• workers receive suitable information, instruction, supervision and consultation
• information is being shared when designs, sequencing or site conditions change
• domestic-client duties have been allocated correctly where the project is domestic
• the project arrangements are reviewed as the project develops rather than left as a one-off appointment exercise

This is a practical prompt rather than a substitute for project-specific judgement. CDM arrangements should be proportionate to the scale, complexity and risks of the project.