Tue 07 Jul 2026

Construction (Design and Management) Regulations 2015 - What do Contractors Need to Do?

An essential consideration for anyone commencing a construction project in the UK is an understanding of, and compliance with, the Construction (Design and Management) Regulations 2015 ("the CDM Regs"). These regulations set out the requirements for all duty holders involved in a construction project to ensure that the works are carried out as safely as possible.

Our previous two articles in this series Construction (Design and Management) Regulations 2015 - What do Clients need to do? | MFMac and Construction (Design and Management) Regulations 2015 - What do Designers need to do? | MFMac discussed the duties of clients and designers under the CDM Regs. This article will focus on the role of contractors, what they are required to do under the CDM Regs and the practical steps to ensure compliance.

Who is a "Contractor" under the CDM Regs?

A Contractor under the CDM Regs is defined as a person or organisation who, "in the furtherance of a business, carries out, manages or controls construction work". "Construction Work" is also defined within the CDM Regs and includes works such as renovations, maintenance, excavation and installing structures or equipment (such as pipelines). This is a wide-ranging definition and any person carrying out works of this type will hold responsibilities under the CDM Regs.

It is competent for a person or organisation to hold more than one role under the CDM Regs and therefore someone appointed as a Contractor may also hold designer or client duties.

What duties do Contractors have under the CDM Regs?

Contractors are responsible for the health and safety requirements under the "construction phase" of a project. This is the period between works starting on a site and completion of the works.

In the first instance, any contractor must ensure that the Client or Clients under the project are aware of the duties that they are responsible for under the CDM Regs. The Contractor should also be satisfied that, based on the scope of the project, they have the necessary skills, knowledge and experience to be able to complete the works safely.

Regulation 15 sets out the primary obligations for contractors, which are underpinned by the principles of prevention. These principles are a framework to effectively evaluate and control health and safety risks during a project.

Contractors must ensure that they plan, manage and monitor any works that they are directly responsible for or have subcontracted to others, with a focus on mitigating health and safety risks. Any personnel that a Contractor hires to carry out construction work must have the necessary training and experience for the work they are tasked with. Subcontractors need to be provided with a suitable site induction and be aware of the health and safety procedures for the site and activities taking place.

Part 4 of the CDM Regs outlines general requirements for all construction sites. A Contractor or Principal Contractor will have primary responsibility for carrying out these requirements. These include:

  1. ensuring safe access and egress to the construction site
  2. keeping the site in good order with suitable security
  3. ensuring adequate health and safety measures for demolition or dismantling work
  4. ensuring traffic routes are kept clear and unobstructed

There are also activity-specific requirements for works which include excavations, work with water and the use of vehicles.

What is a Principal Contractor and when are they needed?

Where there is more than one contractor involved in a project, one of the contractors will be appointed as Principal Contractor. As well as holding the duties already outlined, the Principal Contractor holds additional responsibilities prior to and during the construction phase.

What duties do Principal Contractors have?

Firstly, the Principal Contractor must prepare a construction phase plan prior to starting the works (or arrange for someone to prepare this on their behalf). The purpose of this document is to provide clear instructions for managing the health and safety matters on site. There will be liaison with the Principal Designer to compile this document. It must be reviewed and revised throughout the project as required.

The Principal Contractor should also use the principles of prevention to co-ordinate each phase of the works and liaise with each contractor throughout the process to lower any risks to health and safety, "so far as reasonably practicable". In practice, there is overlap here with the general contractor duties, including ensuring site inductions take place and that steps are taken to avoid unauthorised access to the site by members of the public.

There is an overarching duty on the Principal Contractor to engage with workers on site to ensure that the right measures are in place and that they are working effectively. Principal Contractors must consult with workers throughout the process and workers should be encouraged to provide input into any matters involving their health, safety and wellbeing.

What happens if a Contractor doesn’t comply with requirements under the CDM Regs?

We have outlined earlier in the article series what enforcement powers are available to HSE and other bodies and what steps can be taken if a duty holder doesn’t comply with their duties under the CDM Regs. This information can be found here - Construction (Design and Management) Regulations 2015 - What do Clients need to do? | MFMac.

Case studies highlight that contractor breaches are often associated with either a lack of planning of the works prior to starting or failing to sufficiently assess all risks associated with an activity. A high-profile example of this was highlighted in the Fatal Accident Inquiry into the death of Shea Ryan, a child who fell down an unsecured manhole on a construction site in Drumchapel. It was found that there had been a failure to sufficiently assess the risk of unauthorised access to the site out of hours, which led to the site not being adequately secured.

I'm a Contractor on a project; what practical tips can you give me?

There are wide-ranging duties placed on contractors that are applicable both prior to and during the works to be completed. Construction work can be high risk by nature, and it is vital that any risks posed by either the site location or the activities taking place are recognised and mitigated as far as possible for the entirety of the construction works.

Contractors should therefore first ensure that they have received all of the information from the client and designer(s) that they need to assess the scope of the works and confirm that they have the requisite skills needed to complete the works and conduct the necessary risk assessments.

A key component of effective management under the CDM Regs is ensuring good communication and engagement with other contractors and duty holders during the project. Certain junctures should be set during the project for when plans will be reviewed. This could be at certain set stages and/or when certain agreed triggers arise. For example, there could be a requirement to review the construction phase plan every three months, but also any time an accident is reported.

Best practice includes ensuring that excellent records are kept at all stages of the construction work (and prior to it, if applicable). These should evidence the information that has been used to assess the risks and a clear trail of any audits or updates to those plans. It is not sufficient to simply have a policy as part of a tick-box exercise - the policy or assessment must be adequately detailed to ensure that each activity can take place safely.

If you are looking to speak to someone about the duties placed on designers under the CDM Regs in more detail, or any health & safety steps you need to take when managing a project, please do contact a member of our health & safety compliance team and they would be happy to assist.

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