13th January, 2021

What Is CDM In Construction?

CDM applies to every construction project. If you work in or become involved with the construction industry you are likely to hear the term CDM. CDM needs to be applied before, during and after the project. But what is CDM?

What Is CDM In Construction? header image

What does CDM stand for?

In construction, CDM stands for the Construction (Design and Management) Regulations. This is a set of health and safety regulations that apply to every construction project in Great Britain. It's a bit of a mouthful, hence the abbreviation to the much quicker term, CDM.

“project” means a project which includes or is intended to include construction work and includes all planning, design, management or other work involved in a project until the end of the construction phase;

The Construction (Design and Management) Regulations 2015 Interpretation

What are the Construction (Design and Management) Regulations?

The Construction (Design and Management) Regulations, known as the CDM regulations, are a set of health and safety regulations that apply specifically to construction projects. These regulations apply to all construction projects of all sizes and were most recently updated in 2015.

The aim of the CDM regulations is to improve health and safety in construction work, both during the project, and for any future work, use and maintenance of the building or structure. To achieve its objectives the CDM regulations place duties on virtually everyone involved in construction work, particularly on key members of the project team such as the client, designers and contractors.

The CDM regulations also cover other health and safety requirements in addition to duty holders, including welfare requirements and general requirements for all construction sites, such as security, traffic, emergency procedures and lighting.

construction site hard hats

What is CDM 2015?

CDM 2015 is the latest version of the CDM Regulations. CDM has been around since 1994, but the regulations have been through a few changes. First in 2007, and then again in 2015.

These Regulations have been revised several times so far...

In its latest form, CDM 2015 has 5 key duty holders:

Each of these duty holders has important duties they must discharge to comply with CDM. Click on any of the duty holders above to get a free CDM step-by-step guide to follow for each duty holder. CDM has evolved over the years, but the essence of the regulations stays the same, to ensure that construction work is carried out safely.

What does CDM mean in construction?

If you are involved in a construction project, you need to know about CDM. The regulations apply to nearly every person involved in the project. If you are a client, having construction work carried out - you have client duties. If you are a contractor, carrying out work - you have contractor duties. If you are a designer, drawing up plans or putting together specifications - you have designer duties.

8.—(1) A designer (including a principal designer) or contractor (including a principal contractor) appointed to work on a project must have the skills, knowledge and experience, and, if they are an organisation, the organisational capability, necessary to fulfil the role that they are appointed to undertake, in a manner that secures the health and safety of any person affected by the project.

The Construction (Design and Management) Regulations 2015 General duties

The CDM regulations apply to all construction projects of any type, including domestic, and of any duration or size. Small builders and individual trades need to know about CDM just as much as the big corporations. In fact, the definition of construction work under CDM covers a lot more than you might expect. It includes maintenance, re-decoration, assembly of prefabricated elements and even certain types of cleaning.

Having work carried out on your home? CDM applies to domestic projects as well. Domestic clients don't have the same duties as commercial ones or businesses. But that doesn't mean you can forget about CDM. If you work for a domestic client, as a contractor or designer, you can actually have extra CDM duties to comply with.

Find out more about CDM duties when working on domestic projects in our blog post, CDM 2015 Working For Domestic Clients.

What does CDM require?

Whatever type of construction project you are working on, clients have client duties, designers have designer duties, and contractors have contractor duties. If there is more than one contractor involved in the project (including subcontractors), a principal contractor and a principal designer need to be appointed by the client. They have extra duties, in addition to contractor and designer duties.

The principal designer is in overall control of health and safety at the pre-construction phase. This means gathering health and safety information from the client and other duty holders, passing this on to those that need it. It means considering health and safety in the design and making sure designers comply with their duties.

CDM principal designer

The principal contractor is in overall charge of health and safety at the construction phase. This involves reviewing health and safety information and planning the work on site. Setting out site rules and safe working procedures. It means considering health and safety during the build and making sure contractors comply with their duties.

The requirements of CDM don't just fall on one person to take care of. Each of the duty holders needs to work together to make sure that the project can be carried out without risk to health and safety. This means planning the work and completing the work safely on site. It also means making sure that future use, cleaning and maintenance can be carried out safely.

Find out more in CDM 2015 roles and responsibilities.

The regulations also require certain CDM documents to be produced, to record the steps that have been taken to reduce risk and to communicate health and safety information to the project team.

Before work starts on site, the pre-construction information will be used to gather health and safety information on existing hazards. During work, the construction phase plan will be in place to detail how construction risks will be controlled. And, after work is finished, the health and safety file is produced to pass key information forward to those using and maintaining the structure.

Get more detail information on the CDM documents you need in CDM 2015 documents explained.

Some projects also need to be notified to the HSE. These are larger construction projects that meet certain notification criteria. Projects with more than 20 people at any one time that last over 30 days. Or projects involving over 500 person days.

Not sure if your project needs to be notified? Use our free CDM notification calculator to find out.

All duty holders have responsibilities to provide health and safety information and comply with the requirements under CDM. This includes knowing your own duties and also ensuring other duty holders understand the requirements. Work should not progress unless CDM has been complied with at each stage.


CDM must be followed on every construction project, it's the law. What happens if you don't comply with CDM? Find out in CDM 2015 Prosecutions (Breaches, Fines And Prison Time).

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This article was written by Emma at HASpod. Emma has over 10 years experience in health and safety and BSc (Hons) Construction Management. She is NEBOSH qualified and Tech IOSH.

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