Principal Contractor duties explained

Who is the Principal Contractor under CDM 2015?

A Principal Contractor is the contractor appointed by the client to control the construction phase of a project involving more than one contractor. The appointment must be made in writing. HSE guidance: principal contractors, roles and responsibilities (opens in a new tab)

The role is required where more than one contractor is involved, or where it is reasonably foreseeable that more than one contractor will work on the project. The Principal Contractor needs the skills, knowledge and experience, and where the appointment is an organisation, the organisational capability, to carry out the role in a way that secures health and safety. HSE guidance: are you a principal contractor? (opens in a new tab)

The Principal Contractor is not simply the largest contractor on site or the business holding the biggest package of work. The key issue is who has been appointed to lead, manage and coordinate the construction phase.

What are the main duties of the Principal Contractor?

Under CDM 2015, the Principal Contractor must plan, manage, monitor and coordinate health and safety during the construction phase. Read Regulation 13 on legislation.gov.uk: duties of a principal contractor in relation to health and safety at the construction phase (opens in a new tab)

That means creating workable arrangements for how construction risks will be controlled, coordinating the contractors carrying out the work, checking those arrangements are being followed and adapting them as the project changes.

The role also includes liaising with the client and Principal Designer, preparing and maintaining the construction phase plan, organising cooperation between contractors, providing suitable site inductions, preventing unauthorised access, consulting workers and ensuring welfare facilities are provided throughout the construction phase. HSE duty-holder summary: summary of duties under CDM 2015 (opens in a new tab)

Plan, manage, monitor and coordinate the construction phase

The Principal Contractor should take the lead on health and safety management once the project moves into the construction phase. This starts with understanding the work, the foreseeable risks, the interfaces between contractors and the information supplied during pre-construction. HSE guidance: principal contractors, roles and responsibilities (opens in a new tab)

Planning is not a one-off activity. The Principal Contractor should keep arrangements under review as sequencing changes, new contractors arrive, design decisions are developed or site conditions change. HSE guidance: planning for construction work (opens in a new tab)

Management should be proportionate to the project. A smaller project may need relatively simple arrangements, while a complex multi-contractor project may require more formal coordination, inspections, meetings and controls.

Prepare and maintain the construction phase plan

A written construction phase plan must be prepared before the construction phase begins. On a project involving more than one contractor, this is the responsibility of the Principal Contractor. HSE construction phase plan guidance (CIS80): CDM 2015 construction phase plan (opens in a new tab)

The plan should set out the health and safety arrangements for the construction phase, relevant site rules and the specific measures needed for work involving particular risks. It should reflect the actual project rather than becoming a generic document that is filed and forgotten.

The Principal Contractor must implement the plan and keep it under review, revising it when necessary so that it remains suitable for the work being carried out. HSE guidance: principal contractors, roles and responsibilities (opens in a new tab)

Coordinate contractors and organise cooperation

Construction work often creates risks at the interfaces between different trades, work areas and activities. The Principal Contractor must organise cooperation between contractors and coordinate their work so that applicable health and safety requirements are implemented consistently. Read Regulation 13 on legislation.gov.uk: duties of a principal contractor in relation to health and safety at the construction phase (opens in a new tab)

This includes making sure contractors understand the relevant parts of the construction phase plan, know the site arrangements and have the information they need to work safely alongside others.

Coordination is especially important where one contractor’s activity changes the conditions for another, for example temporary works, lifting operations, isolations, access arrangements, traffic routes or changes to sequencing.

Check competence and provide site-specific information

When appointing contractors or workers, the Principal Contractor should check that they have the skills, knowledge, training and experience needed for the work, and where relevant that an organisation has suitable organisational capability. HSE guidance: principal contractors, roles and responsibilities (opens in a new tab)

Workers must also receive a suitable site-specific induction. The induction should explain the arrangements that matter on that project, rather than relying only on generic company information. Read Regulation 13 on legislation.gov.uk: duties of a principal contractor in relation to health and safety at the construction phase (opens in a new tab)

Additional information, instruction and training should be provided where needed, with suitable supervision arrangements for the work being undertaken.

Prevent unauthorised access and maintain site security

The Principal Contractor must take reasonable steps to prevent unauthorised people from gaining access to the construction site. Read Regulation 13 on legislation.gov.uk: duties of a principal contractor in relation to health and safety at the construction phase (opens in a new tab)

What is reasonable will depend on the location and risks. A live public environment, occupied premises or a site close to schools, roads or residential areas may need different controls from an isolated controlled site.

Site boundaries, access points, visitor arrangements and interfaces with members of the public should therefore form part of the project’s construction-phase management arrangements.

Provide and maintain suitable welfare facilities

Suitable welfare facilities must be available from the start of the construction phase and maintained for the duration of the work. Read Regulation 13 on legislation.gov.uk: duties of a principal contractor in relation to health and safety at the construction phase (opens in a new tab)

The Principal Contractor should make sure the facilities are appropriate for the workforce and the nature of the project. Welfare is not something to add once the site is established; it forms part of the arrangements needed before construction work starts.

Consult and engage workers

The Principal Contractor must make arrangements for workers to be consulted and engaged on matters that affect their health, safety and welfare. HSE guidance: principal contractors, roles and responsibilities (opens in a new tab)

Workers often have direct knowledge of how tasks are actually being carried out and where arrangements are difficult to apply. Effective consultation can therefore help identify problems early and improve practical controls.

The approach should suit the workforce and project. It might include briefings, toolbox talks, worker representatives, coordination meetings or other routes for raising and resolving concerns.

Liaise with the client and Principal Designer

The Principal Contractor does not operate in isolation. They must liaise with the client and Principal Designer for the duration of the project so that information and risk-management decisions are coordinated across the project team. Read Regulation 13 on legislation.gov.uk: duties of a principal contractor in relation to health and safety at the construction phase (opens in a new tab)

The Principal Contractor should share information with the Principal Designer that is relevant to the planning, management, monitoring and coordination of the pre-construction phase, including information arising from construction that may affect design decisions or the health and safety file. HSE L153 guidance: managing health and safety in construction, Regulation 13 guidance (opens in a new tab)

Good liaison is particularly important where design develops during construction or where site conditions require changes to the planned approach.

Principal Contractor under CDM vs Building Regulations

The term “Principal Contractor” is also used under the Building Regulations dutyholder regime. The CDM role and the Building Regulations role are separate legal functions, even though the same organisation may be appointed to both. GOV.UK guidance: design and building work, meeting building requirements (opens in a new tab)

The CDM Principal Contractor is focused on managing health and safety during the construction phase. The Building Regulations Principal Contractor has duties connected with ensuring building work complies with the Building Regulations.

Where the same organisation is appointed to both roles, the appointments and responsibilities should still be clear. Where different organisations hold the roles, they need to cooperate and share relevant information.

Common Principal Contractor mistakes

Treating the construction phase plan as a one-off document

The plan should reflect the live project and be reviewed and revised as the work changes.

Assuming each contractor can manage in isolation

The Principal Contractor has a coordination role across contractors and interfaces, not just responsibility for their own workforce.

Using a generic induction

Induction should be site-specific and communicate the arrangements and risks that matter on that project.

Leaving welfare until after work starts

Suitable facilities should be in place from the start of the construction phase.

Failing to involve workers

Worker consultation is a specific part of the Principal Contractor role and can reveal practical issues that management arrangements miss.

Weak liaison with the Principal Designer

Design and construction information should continue to flow throughout the project, especially where design develops during the construction phase.

Principal Contractor duties checklist

• Confirm the Principal Contractor appointment is in writing and made before the construction phase begins.
• Review the pre-construction information and relevant design information.
• Prepare the construction phase plan before construction starts.
• Plan, manage, monitor and coordinate the construction phase.
• Put suitable arrangements in place for cooperation and coordination between contractors.
• Check the capability of contractors and workers appointed to the project.
• Provide suitable site-specific inductions and any additional information, instruction and training needed.
• Provide appropriate supervision and make sure site rules and relevant parts of the construction phase plan are understood.
• Take reasonable steps to prevent unauthorised access.
• Provide and maintain suitable welfare facilities from the start of the construction phase.
• Consult and engage workers on health, safety and welfare matters.
• Liaise with the client and Principal Designer and share relevant information.
• Review and revise construction-phase arrangements as the project changes.

What happens on a domestic project?

Where a domestic project involves more than one contractor, the Principal Contractor will normally take on the domestic client duties as well as carrying out their own Principal Contractor duties. HSE duty-holder summary: summary of duties under CDM 2015 (opens in a new tab)

If the domestic client has made a written agreement with the Principal Designer for the Principal Designer to carry out the client duties, the Principal Contractor works to that arrangement instead.

The construction-phase duties of the Principal Contractor still apply. The domestic-client provisions change who carries out the client functions; they do not remove the need to manage the construction phase properly.