Contractor Appointment Letter

1. What Is a Contractor Appointment Letter?

A Contractor Appointment Letter is the written agreement by which a Principal Contractor — or a client on single-contractor projects — formally engages a contractor or subcontractor to carry out specific construction work on a project, including explicit acknowledgement of that contractor's CDM 2015 duties.

This document covers the appointment of individual contractors and subcontractors within the supply chain. It is distinct from the Principal Contractor appointment, which is the client's appointment of the lead contractor who manages the construction phase on projects with more than one contractor. While both are governed by CDM 2015, they serve different purposes, are issued by different parties, and carry different obligations.

2. PC vs Individual Contractor — The Difference

There is frequent confusion between the appointment of a Principal Contractor and the appointment of individual contractors within the supply chain. They are fundamentally different appointments governed by different regulations, issued by different parties, and carrying different duties. The table below sets out the distinction clearly.

3. Is a Written Appointment Letter Required?

CDM 2015 does not explicitly require individual contractor appointments to be in writing. Unlike the Principal Contractor appointment — where a written appointment is strongly implied by the regulations and universally expected — the appointment of subcontractors and individual contractors has no express written requirement in the statute.

However, CDM 2015 Regulation 8(3) is unambiguous: the appointing party must take reasonable steps to satisfy themselves that the contractor has the skills, knowledge, experience and organisational capability to carry out the work in a way that secures the health and safety of any person affected. A written appointment letter is the primary means of documenting that this duty has been discharged.

• That the Regulation 8(3) competence check was carried out before appointment
• That the contractor was made aware of their specific CDM 2015 duties
• That the scope of work, site rules, and CPP requirements were communicated
• That the contractor acknowledged receipt of relevant pre-construction information
• That the duty holder relationship and reporting lines were established in writing

4. Who Is a Contractor Under CDM 2015?

CDM 2015 defines a contractor broadly. The term covers far more than main contractors and traditional subcontractors. The legal definition captures anyone who carries out, manages, or controls construction work — including those who may not think of themselves as contractors at all.

“Contractor means any person (including a non-domestic client) who, in the course or furtherance of a business, carries out, manages or controls construction work.”— CDM 2015 Regulation 2 (Interpretation)

The following all require a Contractor Appointment Letter when engaged on a CDM project:

• Subcontractors — any specialist trade contractor engaged by the PC (steelwork, M&E, groundworks, roofing, cladding, etc.)
• Labour-only subcontractors — even where the PC provides all materials, plant, and supervision, the labour-only subcontractor is still a contractor under CDM 2015
• Self-employed individuals — a self-employed bricklayer, plasterer, or electrician working on a construction project is a contractor and carries CDM duties
• Specialist contractors — asbestos removal companies, demolition contractors, scaffolding contractors, and piling contractors all fall within the definition
• Utility companies — where a utility company carries out construction work (e.g. new service connections, diversions), they are a contractor under CDM 2015
• Facilities management contractors — where FM contractors carry out work that meets the definition of construction work (e.g. structural maintenance, refurbishment), they are contractors under CDM 2015

5. What Are a Contractor's CDM Duties?

CDM 2015 Regulation 15 sets out the duties that every contractor must comply with on every construction project. These duties begin from the moment of appointment — not from the moment the contractor arrives on site. The appointment letter should reference each duty so the contractor cannot later claim they were unaware of their obligations.

“A contractor must not carry out construction work in relation to a project unless satisfied that the client is aware of the duties owed by the client under these Regulations.”— CDM 2015 Regulation 15(1)

Regulation 15(1) — Duty not to start work

The contractor must not begin construction work unless satisfied that the client is aware of their CDM duties. This is a positive obligation — the contractor must take active steps to verify client awareness, not simply assume it. The appointment letter can serve as evidence that this check was performed.

Regulation 15(2) — Planning, managing and monitoring

The contractor must plan, manage and monitor construction work carried out by them or under their control so that it is carried out without risks to health or safety. This includes ensuring that any contractor they in turn appoint is also subject to a competence check.

Regulation 15(4) — Providing information and instructions

The contractor must provide every worker under their control with appropriate supervision, instructions and information. Workers must know the risks specific to the work they are carrying out, the measures in place to control those risks, and any site rules established in the Construction Phase Plan.

Regulation 15(7) — Not starting work without a CPP

A contractor must not carry out construction work on a project with more than one contractor unless satisfied that a Construction Phase Plan has been drawn up. The contractor is not required to produce the CPP — that is the PC's duty — but they must not start work without one being in place.

Regulation 15(9) — Welfare facilities

On a project with only one contractor, that contractor must ensure that suitable welfare facilities are provided from the start of construction work. On multi-contractor projects, this duty falls to the PC — but individual contractors must cooperate with the PC in ensuring welfare provision is adequate for their workers.

Regulation 15(11) — Compliance with directions and site rules

Every contractor must comply with any directions given by the Principal Designer or Principal Contractor, and with the site rules set out in the Construction Phase Plan. Non-compliance by a subcontractor does not relieve the PC of their management duty — but it does create direct liability for the non-compliant contractor.

6. What Should the Appointment Letter Contain?

A well-drafted Contractor Appointment Letter should cover all the elements necessary to establish the duty holder relationship, document the competence check, and ensure the contractor understands their CDM obligations and the site-specific requirements. The following table sets out the essential content.

RAMS — Risk Assessments and Method Statements — are a critical element of the appointment process. The appointment letter should require the contractor to submit activity-specific RAMS before commencing any work on site. These should be reviewed and accepted by the PC before the contractor mobilises. Generic RAMS that do not reference the specific site, the specific work, or the specific hazards identified in the pre-construction information are not acceptable and should be rejected.

7. Checking Contractor Competence

CDM 2015 Regulation 8(3) requires the appointing party to take reasonable steps to satisfy themselves that the contractor has the skills, knowledge, experience and organisational capability necessary to carry out the work safely. This is not a box-ticking exercise — it requires genuine assessment proportionate to the complexity and risk of the work being undertaken.

What ‘reasonable steps’ means in practice

The HSE does not expect an exhaustive audit of every contractor. What constitutes ‘reasonable steps’ depends on the nature and complexity of the work. For a straightforward trade subcontractor carrying out low-risk work, verifying SSIP accreditation, checking insurance, and confirming CSCS cards may be sufficient. For a demolition contractor, an asbestos removal specialist, or a contractor carrying out work at height on a complex structure, significantly more rigorous checks are appropriate — including review of previous project performance, direct assessment of key personnel, and detailed scrutiny of RAMS.

The key principle is proportionality: the higher the risk, the more thorough the check must be. What is not proportionate is doing nothing at all — or relying solely on the fact that a contractor has been used before. Past performance on a different project does not automatically satisfy Regulation 8(3) for the current project, particularly where the scope or risks are materially different.

8. Common Mistakes

9. A Real-World Example

A Principal Contractor was engaged on the refurbishment of a 1970s council housing block in Birmingham. The project involved strip-out of existing kitchens and bathrooms across 48 flats, replacement of communal heating pipework, and external envelope repairs. The PC subcontracted the mechanical works to a specialist M&E contractor and the asbestos removal to a licensed removal company. The strip-out and general building works were subcontracted to a smaller local contractor. The PC issued formal Contractor Appointment Letters to the M&E contractor and the asbestos removal company, including competence checks, CPP provision, and RAMS requirements. However, the strip-out contractor — engaged through a verbal agreement based on previous working relationships — received no appointment letter, no competence check documentation, and was not formally provided with the Construction Phase Plan.

During week six, a strip-out operative fell through a fragile ceiling panel in a communal corridor while accessing pipework above. The operative sustained serious injuries. The HSE investigation found that the strip-out contractor had not been provided with the pre-construction information identifying fragile surfaces in the building, had not received the CPP section covering work at height controls, and had no site-specific RAMS for the work being undertaken. The PC could not demonstrate that any Regulation 8(3) competence check had been carried out for the strip-out contractor, because no written appointment existed.

The HSE prosecuted both the PC and the strip-out contractor. The PC was fined for failing to plan, manage and monitor construction work and for failing to take reasonable steps to check contractor competence before appointment. The strip-out contractor was fined for failing to plan and manage their own work and for failing to provide their workers with adequate information and instruction.

The formal appointment of the M&E contractor and asbestos removal company demonstrated CDM compliance for those packages. The absence of a written appointment for the strip-out contractor made prosecution straightforward. The same PC, the same project, the same CPP — but one missing appointment letter was the difference between a defensible position and a conviction.

10. How It Relates to Other Documents

The Contractor Appointment Letter sits within a broader CDM documentation framework. Understanding the relationships ensures that each document serves its intended purpose without duplication or gaps.

11. Frequently Asked Questions