What are the CDM Regulations?

 CDM Regulations 2015

The Construction (Design and Management) Regulations 2015, more commonly known as CDM, are the main set of regulations for managing the health, safety and welfare of construction projects.

CDM 2015 applies to all building and construction work including new builds, demolition, refurbishments, extensions, conversions, ground keeping and general facilities work. 

What are the legal requirements under CDM?

Legal duties are placed on all of the parties involved in construction projects.

There are four parties specified under CDM 2015, which are:


There are two types of clients:

  • Commercial - any individual or organisation that carries out a construction project as part of a business.
  • Domestic - any individual who has construction work carried out on their home, or the home of a family member.

CDM parties

Principal Contractor / Contractor

The Principal Contractor is appointed by the Client to control the construction phase of any project involving more than one contractor.

A contractor is anyone who directly employs or engages construction workers, or manages construction work. This include sub-contractors, and individual self-employed workers or businesses that carry out, manage or control construction work.

Principal Designer / Designer

A principal designer is an organisation or individual appointed by the client who is responsible for planning, monitoring and managing the pre-construction phase of any project involving more than one contractor. If the client does not appoint a Principal Designer, the Client takes on the role by default.

A designer is an organisation or individual whose business involves preparing or modifying designs for construction projects, or arranging for / instructing others to do this.


A worker is an individual who carries out the physical work involved in building, altering, maintaining or demolishing buildings or structures. This includes plumbers, electricians, scaffolders, painters, decorators and labourers.

Everyone with duties under CDM 2015 must cooperate with others involved with the project, working with each other to ensure health and safety is suitably managed.

CDM notifiable projects

What is a notifiable project?

Certain construction projects need to be notified to the Health and Safety Executive (HSE). A project is notifiable where:

  • The construction phase is expected to last longer than 30 working days and have more than 20 workers working simultaneously at any point in the project; or
  • If the construction phase exceeds 500 person days of construction work.

The Client is responsible for notification, unless the duties of the client have been passed onto the Principal Contractor, then they are responsible for notification.

The notification must be made on the online form (F10) on the HSE website as soon as practicable before the construction phase begins. Click here to view or complete the form.


Our CDM Regulations 2015 online course provides an overview of the legal requirements of the Construction (Design and Management) Regulations 2015, and goes into more detail about the specific duties and relevant documentation such as the construction phase plan and health and safety file. View more information about the course here.