CDM 2015 Duties Explained for Site Managers
The Construction (Design and Management) Regulations 2015, known as CDM 2015, set out how health, safety and welfare should be managed on construction projects in Great Britain. If you run a site, you do not need to memorise every clause, but you do need to know which duty holder you are and what is expected of you. This guide breaks it down in plain English.
What CDM 2015 is for
CDM 2015 applies to all construction work in Great Britain, from a small domestic job to a major project. The aim is straightforward: to make sure the right people manage risk at the right time, from design through to handover, so that work is planned, coordinated and carried out safely. It does this by defining a set of duty holders and giving each one specific responsibilities.
The CDM 2015 duty holders
It helps to understand the full picture, because as a site manager your work connects with several of these roles. The main duty holders are summarised below.
| Duty holder | In short, who they are and what they do |
|---|---|
| Client | The organisation or individual the project is for. They must make suitable arrangements for managing the project, including appointing other duty holders and allowing adequate time and resources. |
| Principal designer | Appointed by the client on projects with more than one contractor. Plans, manages and coordinates health and safety during the pre construction (design) phase. |
| Principal contractor | Appointed by the client on projects with more than one contractor. Plans, manages and coordinates health and safety during the construction phase on site. |
| Designers | Anyone who prepares or modifies designs. They must eliminate, reduce or control foreseeable risks through their design decisions. |
| Contractors | Anyone who carries out, manages or controls construction work. They plan, manage and monitor their own work and comply with directions from the principal contractor. |
| Workers | The people carrying out the work. They must look after their own and others' safety, follow training and report risks. |
Single contractor versus multiple contractors
This is a key distinction in CDM 2015. Where there is only one contractor on a project, that contractor takes on the duties that would otherwise sit with the principal contractor, and the role of principal designer and principal contractor is not separately required in the same way. Where there is more than one contractor, the client must appoint a principal designer and a principal contractor in writing. If you are unsure how your project is categorised, confirm it with the client and check current HSE guidance.
What the principal contractor must do
If you are running the site as, or on behalf of, the principal contractor, your core responsibilities generally include:
- Planning, managing and monitoring the construction phase so that work is carried out safely.
- Coordinating the work of all contractors on site so their activities fit together without creating risk for each other.
- Preparing and keeping the construction phase plan current.
- Organising cooperation between contractors and sharing relevant information.
- Ensuring suitable site induction, welfare facilities and site security.
- Consulting and engaging with workers on health and safety matters.
What every contractor must do
If you are a contractor rather than the principal contractor, you still carry direct CDM duties, including:
- Planning, managing and monitoring your own construction work so it is carried out safely.
- Making sure anyone you employ or appoint has the necessary skills, knowledge, training and experience.
- Following the directions of the principal contractor and the construction phase plan.
- Providing appropriate supervision, information and instruction to your workers.
- Not starting work until you have taken reasonable steps to ensure welfare facilities are in place.
The construction phase plan
A construction phase plan is required for every construction project under CDM 2015, including domestic projects. It records the health and safety arrangements, site rules and specific measures for the work being carried out. It does not need to be a huge document. For a smaller, lower risk job it should be proportionate, but it must genuinely reflect how the site will be managed. Keeping it current as the project changes is part of the duty.
Records, site diaries and demonstrating compliance
CDM is about managing risk, but being able to show what you did matters. A well kept site diary, induction records, daily briefings, inspection records and updated risk documents all help demonstrate that the site was being managed properly. If something goes wrong, contemporaneous records are far more persuasive than memory. Many site managers keep a daily site diary precisely so there is a clear, dated account of conditions, decisions, deliveries, visitors and any incidents.
Common CDM 2015 pitfalls
- Assuming small or domestic jobs are exempt. CDM applies to construction work generally, and a construction phase plan is needed even on small projects.
- No clear appointment in writing. On multi contractor projects the principal designer and principal contractor should be appointed in writing by the client.
- A construction phase plan that is never updated. It should reflect the site as it actually is, not how it looked at tender.
- Poor coordination between trades. Much CDM risk comes from one trade affecting another. Coordination is a core duty, not an extra.
- Thin records. If it was not written down, it is hard to show it happened.
Frequently asked questions
Does CDM 2015 apply to domestic and small projects?
Yes, CDM 2015 applies to construction work generally, including small and domestic projects. The specific arrangements should be proportionate to the work, and a construction phase plan is required. Check current HSE guidance for how the rules apply to domestic clients.
Is a site manager a CDM duty holder?
Site manager is not one of the named CDM duty holders, but site managers usually carry out duties on behalf of the contractor or principal contractor, so the responsibilities apply through that role.
When is a principal contractor required?
When there is, or is likely to be, more than one contractor on the project, the client must appoint a principal contractor in writing. With a single contractor, that contractor takes on the relevant duties.
Is a construction phase plan always needed?
A construction phase plan is required for every construction project under CDM 2015. The detail should be proportionate to the size and risk of the work.
Conclusion
CDM 2015 is less daunting once you see it as a clear set of roles, each with defined responsibilities, all pointing at the same goal of managing risk properly. As a site manager you sit at the centre of much of the day to day delivery, so knowing your duty holder position, keeping the construction phase plan current, coordinating the trades and keeping good records is most of the battle. Where anything is unclear for your specific project, confirm it with the client and check current HSE guidance.
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This article is general guidance for construction work in Great Britain and is not legal advice. For requirements specific to your project, check current HSE guidance and confirm duty holder appointments with your client.