CDM Regulations Explained: Who's Responsible on a Construction Project?

Quick Summary

The Construction (Design and Management) Regulations 2015 — usually shortened to CDM 2015 — set out who is responsible for health and safety on construction projects. They apply to virtually every project, from a small refurbishment to a major build. If you’re commissioning or running construction work, here’s a plain-English guide to who does what.

What are the CDM Regulations?

CDM 2015 is the main set of regulations covering how construction projects are planned and managed to keep people safe — both during the work and in how the finished building is later used and maintained. The core idea is simple: think about risk early, involve the right people, and coordinate properly so hazards are designed out wherever possible.

Do the CDM Regulations apply to my project?

Almost certainly. CDM 2015 applies to all construction work, whatever the size. What changes with the size and complexity of a project is the level of duties and paperwork involved — not whether the regulations apply at all. Even a homeowner having an extension built is covered, although a domestic client’s duties normally pass to the contractor or principal contractor.

The CDM dutyholders — who's who

CDM 2015 defines a set of “dutyholders”, each with their own responsibilities:

  • Client — the person or organisation the project is for. They set the standard for the whole project: appointing the right people, allowing enough time and budget, and making sure suitable arrangements are in place.
  • Principal Designer — appointed by the client to plan, manage and coordinate health and safety during the pre-construction (design) phase.
  • Principal Contractor — appointed by the client to plan, manage and coordinate health and safety during the construction phase.
  • Designers — anyone who prepares or modifies designs; they must eliminate or reduce risks through their design decisions.
  • Contractors — those carrying out the actual construction work, managing it safely on the ground.
  • Workers — everyone on site, who must be consulted, informed and kept safe.

A principal designer and principal contractor must be appointed whenever there is more than one contractor on a project.

What are the client's duties?

The client carries a lot of influence over how safely a project runs, so CDM places clear duties on them:

  • Appoint the right dutyholders (a principal designer and principal contractor where there’s more than one contractor)
  • Allow adequate time and resources for the work
  • Provide pre-construction information to the design and construction teams
  • Ensure a construction phase plan is in place before work starts
  • Make sure suitable welfare facilities are provided

If you’re commissioning work but construction isn’t your day job, this is exactly where a CDM advisor is invaluable — taking the duties off your plate and translating them into clear, manageable steps.

What about notifiable projects?

Larger projects must be notified to the Health and Safety Executive (HSE) using an F10 form. A project is notifiable if the construction work is scheduled to last longer than 30 working days and have more than 20 workers working at the same time at any point, or to exceed 500 person-days. Notifying the HSE is the client’s responsibility.

Key CDM documents

Three documents come up again and again: the pre-construction information (the health and safety information gathered before work begins), the construction phase plan (how health and safety will be managed during the build), and the health and safety file (information for whoever maintains or later works on the building).

Frequently asked questions

Who is ultimately responsible for CDM on a project?

Responsibility is shared across the dutyholders, but the client sets the tone and has the most influence. The principal designer leads on design-phase safety and the principal contractor on the construction phase.

Do the CDM regulations apply to domestic projects?

Yes, but a domestic client’s duties normally pass to the contractor — or to the principal contractor on larger jobs with more than one contractor.

What happens if you don't comply with CDM?

Non-compliance can lead to enforcement action from the HSE, project delays and, most importantly, a greater risk of harm on site. Getting the right support early is far cheaper than putting problems right later.

CDM can feel daunting, but it doesn’t have to be. Ignis Risk Management acts as a CDM advisor to clients, principal contractors and principal designers, giving you practical, plain-English support at every stage. Based in Ipswich and Lincoln and working UK-wide, we’ll help you stay compliant and keep your project safe. Get in touch to talk it through.