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CDM 2015 Duties Explained: A Practical Guide for SME Contractors

· Last reviewed: 18 February 2026

The Construction (Design and Management) Regulations 2015 — universally known as CDM 2015 — are the primary regulations governing the management of health, safety, and welfare on construction projects in Great Britain. They apply to every construction project, regardless of size, and they impose specific duties on everyone involved in the process, from clients through to individual contractors.

For SME contractors, CDM 2015 can feel like a regulatory maze. This guide cuts through the complexity and explains what the regulations actually require of you, how the duty holder roles work, and where CDM obligations intersect with accreditation requirements.

Disclaimer: This article provides general guidance based on the published text of CDM 2015 and publicly available HSE guidance. TenderReady is not affiliated with the Health and Safety Executive or any accreditation body. This is not legal advice — for specific situations, consult a competent health and safety professional or legal adviser.

What Are the CDM 2015 Regulations?

CDM 2015 replaced CDM 2007 and came into force on 6 April 2015. The regulations apply to all construction work in England, Scotland, and Wales, and are enforced by the Health and Safety Executive (HSE).

CDM 2015 applies to all construction work — new build, demolition, alteration, fitting out, refurbishment, maintenance, and repair. There is no minimum project value or duration threshold, although duties vary depending on whether the project is notifiable and whether it involves more than one contractor.

A project is notifiable to the HSE if the construction work is expected to last longer than 30 working days with more than 20 workers simultaneously at any point, or exceed 500 person days.

The Five Duty Holder Roles

CDM 2015 defines five duty holder roles. Understanding these roles and knowing which ones apply to you is essential.

1. Client

The client is the person or organisation for whom the construction work is carried out. Under CDM 2015, the client has active duties: making suitable arrangements for managing the project, appointing a principal designer and principal contractor (where required), providing relevant site information, and ensuring a construction phase plan and welfare facilities are in place.

For domestic clients, these duties transfer automatically to the contractor or principal contractor.

2. Principal Designer

The principal designer is appointed by the client on projects involving more than one contractor. Their role is to coordinate the pre-construction phase, with particular focus on identifying, eliminating, and controlling foreseeable risks.

As an SME contractor, you are unlikely to hold this role unless you also carry out design work. However, design information relevant to construction risks should flow through to you before you start work.

3. Principal Contractor

The principal contractor is appointed by the client on projects involving more than one contractor. Their duties include planning and coordinating the construction phase, preparing the construction phase plan, organising cooperation between contractors, ensuring site inductions, maintaining welfare facilities, and consulting with workers.

If you are the main contractor on a project with subcontractors, you may well be the principal contractor — bringing substantial coordination duties beyond managing your own workforce.

4. Designer

A designer is anyone who prepares or modifies a design relating to construction work — including contractors who design temporary works, formwork, or elements of the permanent works. If your company designs anything, you have duties under CDM 2015 to eliminate foreseeable risks where possible.

5. Contractor

Every contractor on a construction project has duties under CDM 2015 — this role will always apply to you. Key duties include planning and monitoring your own work, ensuring welfare facilities are in place before starting, verifying worker competence, complying with the construction phase plan, and cooperating with other contractors.

On projects with only a single contractor (no subcontractors), that contractor assumes both the contractor duties and the principal contractor duties.

What CDM 2015 Means for SME Contractors in Practice

Understanding the duty holder roles is only useful if you can translate them into practical action. Here is what CDM 2015 requires of you in your day-to-day operations.

Construction Phase Plan

The construction phase plan sets out the arrangements for managing health and safety during the construction phase. The principal contractor is responsible for preparing it; on single-contractor projects, the contractor must prepare it.

The plan does not need to be lengthy. For smaller projects, a concise plan covering key risks, site rules, emergency procedures, and management arrangements is adequate. What matters is that the plan is specific to the project and is in place before construction work begins. A generic plan that is not tailored to the specific site will not satisfy the regulations.

Competence and Skills

CDM 2015 requires that workers are competent for the tasks they carry out. For SME contractors, this means maintaining up-to-date training records, ensuring relevant CSCS cards and management qualifications (SMSTS, SSSTS, or equivalent) are held and current, verifying the competence of subcontractors you engage, and providing adequate supervision for less experienced workers.

Competence is not just about holding cards and certificates. It encompasses knowledge, experience, and the ability to identify and manage risk in practice. Assessors will look beyond certificates to evidence of how competence is maintained and applied.

Welfare Facilities

Contractors must not start work unless satisfied that adequate welfare facilities are available — toilets, washing facilities, drinking water, changing facilities, rest areas, and facilities for heating food. These are non-negotiable legal requirements.

Cooperation and Coordination

CDM 2015 emphasises cooperation between all parties. You must cooperate with the principal contractor, follow the construction phase plan, attend site inductions, and share information about risks from your work that could affect others.

How CDM 2015 Relates to Accreditation Requirements

CDM 2015 and accreditation are closely linked. Accreditation schemes aligned to the SSIP core criteria assess whether your health and safety management is robust — and those arrangements must address your CDM duties.

Assessors will look for evidence that you understand your duty holder roles, that your health and safety policy addresses CDM requirements (construction phase planning, competence, welfare, cooperation), that you have processes for producing project-specific construction phase plans, and that your training records support your ability to fulfil CDM roles.

A construction SME that can demonstrate practical readiness for CDM duties is well-positioned to achieve and maintain accreditation. Gaps in CDM understanding are frequently flagged during assessments.

For a broader overview of what accreditation schemes require, see our guide: Construction Accreditation Requirements.

Common Misconceptions About CDM 2015

"CDM only applies to large projects." Incorrect. CDM 2015 applies to all construction work. The appointment requirements vary based on contractor numbers, but every project has CDM duties.

"The client is responsible for everything." The client has important duties, but CDM 2015 distributes responsibilities across all duty holders. As a contractor, you have duties regardless of what the client does.

"A construction phase plan is only needed for notifiable projects." A construction phase plan is required for every project with more than one contractor, whether notifiable or not. For single-contractor projects, planning and managing the work safely is still required — and expected by accreditation schemes.

"We are too small for CDM to apply." Size does not determine applicability. A sole trader has CDM duties. The regulations are scalable, but they always apply.

"Holding CSCS cards equals CDM competence." CSCS cards are one element, but CDM competence is broader — it includes the organisational systems, procedures, and oversight needed to manage construction work safely.

Summary

CDM 2015 is not optional, and it applies to every construction SME. The practical steps are clear: understand which duty holder roles apply to your business, ensure your health and safety policy addresses CDM responsibilities, maintain competence records, produce project-specific construction phase plans, and cooperate actively with other parties on every project.

Getting CDM right is about running safe, well-managed projects — which is what wins repeat work and sustains a construction business over the long term.

Sources and References

  • Construction (Design and Management) Regulations 2015 — legislation.gov.uk
  • HSE CDM 2015 guidance: Managing health and safety in construction (L153) — hse.gov.uk
  • HSE CDM overview for contractors — hse.gov.uk
  • HSE construction phase plan guidance — hse.gov.uk
  • Health and Safety at Work etc. Act 1974 — legislation.gov.uk
  • Management of Health and Safety at Work Regulations 1999 — legislation.gov.uk
  • RIDDOR 2013 (Reporting of Injuries, Diseases and Dangerous Occurrences Regulations) — legislation.gov.uk

Disclaimer: This article provides general guidance based on the published text of CDM 2015 and publicly available HSE guidance. TenderReady is not affiliated with the Health and Safety Executive or any accreditation body. This is not legal advice — for specific situations, consult a competent health and safety professional or legal adviser.