CDM Principal Contractor Duties: Your Complete Legal Guide

You've been appointed principal contractor on a multi-contractor project. CDM 2015 says you must "plan, manage, monitor and coordinate" health and safety during the construction phase. But what does that actually mean — in terms of specific actions you need to take, documents you need to produce, and checks you need to make?

This guide breaks down every principal contractor duty under the Construction (Design and Management) Regulations 2015, with the regulation numbers, practical actions, and common failures for each.

For a broader overview of CDM compliance and all five duty holder roles, see our CDM compliance guide.

When must a principal contractor be appointed?

On any project with more than one contractor, the client must appoint a principal contractor in writing before the construction phase begins (Regulation 5). If the client fails to do this, the client themselves takes on the principal contractor duties.

A principal contractor must be a contractor — you can't appoint a consultant, architect, or other non-contractor to this role.

Your duties before construction starts

Prepare the construction phase plan (Regulation 12)

The construction phase plan must be prepared, or at minimum started, before the construction phase begins. It is a living document — not a one-off submission that sits in a drawer.

What it must cover:

A description of the project and its key phases
Management arrangements: who is responsible for what, how communication works, how health and safety is monitored
Site rules (PPE requirements, permits, access control, working hours)
Specific measures for managing high-risk work: work at height, excavation, confined spaces, demolition, hot works
Arrangements for monitoring compliance and reviewing the plan
Emergency procedures

Common failure: Producing a generic template that doesn't reflect the actual project. A construction phase plan that doesn't address site-specific risks won't satisfy an HSE inspection, even if it exists on file.

Verify contractor competence (Regulation 8)

Before any contractor starts work on the project, you must take reasonable steps to satisfy yourself that they have the skills, knowledge, experience, and — if they're an organisation — the organisational capability to carry out the work safely.

What this means in practice:

Check employers' liability insurance (minimum £5M cover, valid certificate)
Check public liability insurance (cover level matching contract requirements)
Verify CSCS cards for operatives (card type must match the work)
Review trade-specific qualifications (Gas Safe, NICEIC, etc.)
Obtain a copy of their health and safety policy (legal requirement for firms with 5+ employees)
Request references or evidence of similar work completed safely

For a full subcontractor compliance checklist, see our guide to managing subcontractors in construction. You can also generate a tailored compliance checklist for your specific project trades, or use our PQQ template to structure your prequalification process.

Obtain pre-construction information (Regulation 4)

The client must provide pre-construction information relevant to the project. As principal contractor, you should ensure you've received this before starting the construction phase plan. This includes:

Information about existing structures, hazards, and services
Previous health and safety files for the site
Information about significant design or construction risks identified by the principal designer

Your duties during construction

Coordinate contractors on site (Regulation 13)

This is the core of the principal contractor role. You must actively coordinate all contractors working on the project to ensure their work doesn't create risks for each other or for other people affected by the work.

What coordination looks like:

Progress meetings that include health and safety as a standing agenda item — not an afterthought
Sequencing work to avoid trade conflicts (e.g., not scheduling work at height above ground-level trades)
Sharing information between contractors about hazards their work creates for others
Resolving conflicts when one contractor's method statement is incompatible with another's

Common failure: Treating coordination as a paperwork exercise. Having signed method statements on file doesn't satisfy Regulation 13 if the actual work on site isn't being actively managed.

Provide site-specific inductions (Regulation 14)

Every worker must receive a site-specific induction before starting work. The induction must cover:

Site-specific hazards and risks (not just generic construction risks)
Emergency procedures and assembly points
First aid arrangements
Site rules and access restrictions
Welfare facilities
How to report hazards, near-misses, and unsafe conditions

Common failure: Using the same generic induction for every project. If the induction doesn't mention the specific risks of this site — asbestos on the third floor, live services in the basement, restricted access near the public highway — it hasn't met the legal requirement.

Consult and engage workers (Regulation 14)

Workers must be consulted about matters affecting their health, safety, and welfare. This isn't a suggestion — it's a legal duty under CDM 2015.

What this means:

Provide mechanisms for workers to raise concerns (toolbox talks, safety notice boards, safety representatives)
Respond to concerns raised — not just log them
Involve workers in risk assessments where practical
Ensure subcontractor employees have the same access to consultation as your direct employees

Prevent unauthorised access (Regulation 13)

You must take reasonable steps to prevent people who are not authorised from entering the construction site. This includes members of the public, children, and workers from other projects.

Ensure welfare facilities (Regulation 13)

Welfare facilities must be provided from day one of the construction phase and maintained throughout. These include:

Toilets and washing facilities
Drinking water
Rest areas with seating and heating
Changing rooms and lockers (if needed)
Facilities for drying wet clothing

Monitor compliance throughout (Regulation 13)

Your responsibilities don't end once contractors are on site and inducted. You must monitor compliance throughout the construction phase.

Proactive monitoring:

Regular site inspections and safety tours
Checking that method statements are being followed
Verifying that PPE is being worn correctly
Confirming that safety controls (edge protection, excavation support, scaffolding standards) are in place

Reactive monitoring:

Investigating accidents, incidents, and near-misses
Reviewing compliance after any changes to work scope or site conditions
Checking subcontractor document expiry dates (insurance, CSCS, qualifications)

Common failure: Only monitoring reactively — investigating after something goes wrong. CDM requires proactive management. If you're only checking compliance when there's an incident, you're not meeting the standard.

Your duties at project completion

Ensure the health and safety file is updated (Regulation 12)

The principal designer is responsible for preparing and maintaining the health and safety file, but the principal contractor must provide information needed for the file and ensure it's passed to the client at the end of the project.

The file should include:

As-built drawings and specifications
Details of materials used (especially hazardous materials)
Information about installed services
Maintenance and cleaning requirements
Residual risks that need managing during future work

Frequently asked questions

Can a client be a principal contractor?

Yes, if the client is a contractor and wishes to take on the role. They must still meet the competence requirements and fulfil all principal contractor duties.

What's the difference between principal contractor and contractor?

Every contractor has duties to plan, manage, and monitor their own work. The principal contractor has additional duties to coordinate all contractors on the project, prepare the construction phase plan, and manage site-wide health and safety. There is only one principal contractor per project.

Who appoints the principal contractor?

The client appoints the principal contractor in writing. On projects with more than one contractor, this appointment must be made before the construction phase begins.

Sources

This guide is for informational purposes and does not constitute legal advice. For project-specific CDM compliance questions, consult a qualified health and safety professional.

Last reviewed: 11 March 2026