CDM – there are still areas of confusion and misunderstanding

21 January 2020

The Construction (Design and Management) Regulations 2015 (CDM 2015) have been in force since April 2015 but there are still many areas of confusion and misunderstanding. 

We answer some of the more common questions, we get asked …

What will be the effect of Brexit on the CDM 2015? 

The CDM 2015 are UK legislation. Regardless of whether (or when) the UK leaves the EU, they will remain in force until amended by the relevant legislative bodies within the UK.

Do the Principal Designer and Principal Contractor need to be a designer and contractor respectively?

The objective of Directive 92/57/EEC — regarding temporary or mobile construction sites — has less to do with design and more to do with co-ordinating health and safety where more than one contractor is involved in a project. 

“Principal Designer” and “Principal Contractor” are the titles given to the person or organisation, to be appointed in writing by the client, they are deemed the duty holders.   They have direct responsibility for carrying out those co-ordination duty roles. It is not necessary for them to be a designer or a contractor although, since there is a requirement for them to have the necessary skill set to allow them to undertake their duties, they should have expertise in this area.  The Principal Designer must be part of the design team and the Principal Contractor will need full  knowledge of the construction phase. 

One thing we stress to our clients is, if they do not formally appoint duty, then the responsibility falls back upon the client. 

Who are the Principal Contractor and Principal Designer?

The requirement under the CDM 2015 is that where there is more than one contractor, a separate duty holder should be appointed to co-ordinate the design and construction phases of a project. The CDM 2015 do not stipulate who that person should be, only that the appointment must be in writing, and they should be appropriately skilled and experienced to carry out the prescribed duty.

It is entirely possible, therefore, that the design and build contractor could be appointed as both Principal Designer and Principal Contractor. However, there can only be one of each on the project, so if another Principal Designer has been engaged, eg during the production of the employer’s requirements, then that appointment will need to end.

Is the Principal Designer responsible for vetting the design?

The Principal Designer may not carry out the actual design, they cannot be held responsible for it. The Principal Designer role under the CDM 2015 is one of co-ordination and management of that design information. It is possible that as part of that process the Principal Designer may be able to provide advice to the people who are ultimately responsible for it, but this is not regarded as a formal check on the design as that is not part of their statutory remit. 

There is nothing to stop them being appointed to carry out that function under a separate agreement, however. The Principal Designer role is not the same as a Lead Designer under a professional service agreement.

Who is responsible for notification?

Under the CDM 2015, at which duty holders are appointed the HSE MUST be notified. 

CDM 2015 state that a project is notifiable if:

“the construction work on a construction site is scheduled to —

  • last longer than 30 working days and have more than 20 workers working simultaneously at any point in the project
  • exceed 500 person days.”

The Regs state: “Where a project is notifiable, the client must give notice in writing to the Executive as soon as is practicable before the construction phase begins.”

To sum that up  – it is the client’s responsibility to notify the HSE. However, in certain circumstances the actual procedure can be delegated, although the client will still be held responsible if it is not done.

Who is responsible under the CDM 2015 for temporary works?

The CDM 2015 contain a new definition of “designer” as an organisation or individual who: “(a) prepares or modifies a design; or (b) arranges for, or instructs, any person under their control to do so.”

This is not a new requirement: while not explicitly mentioned in the previous version of the regulations, it was generally inferred to come under the description of construction work in previous versions of the regulations.

According to L153 Managing Health and Safety in Construction. Construction (Design and Management) Regulations 2015. Guidance on Regulations, designers should “liaise with any other designers, including the principal designer, so that work can be co-ordinated to establish how different aspects of designs interact and influence health and safety. This includes temporary and permanent works designers who should co-operate with each other to ensure that their designs are compatible”. Typically, the choice of temporary work is made by the contractor, so in that respect, they have designer duties as well as contractor duties.

Do the CDM 2015 apply to maintenance work?

The definition of construction under the CDM 2015 includes “the construction, alteration, conversion, fitting out, commissioning, renovation, repair, upkeep, redecoration or other maintenance (including cleaning which involves the use of water or an abrasive at high pressure or the use of corrosive or toxic substances), decommissioning, demolition or dismantling of a structure”.

To the extent that the work falls under the definition of “construction”, therefore, maintenance work IS subject to the provisions of the CDM 2015.

When does a project start and finish?

The CDM 2015 apply to all construction projects, regulation 5 (appointment of the Principal Designer and the Principal Contractor) only applies where it is anticipated that there will be more than one contractor.  This will probably be the case in the majority of projects.

In principle, the design phase will begin when design (as defined in the regulations) commences. In practice, this is likely to be carried out by the first designer. It is reasonable to assume that the appointment of the Principal Designer should be no later that the appointment of the first designer. There are slightly different arguments about the end of the project. It is perhaps reasonable to assume that the construction phase will end once the project reaches practical completion — and the health and safety file, is handed over — but it may be visible to allow for it finishing at the end of the defects liability period.

Can CDM duties and responsibilities be subcontracted?

In short, the answer is NO. Duties under the CDM 2015 are attached to individual roles, so cannot be undertaken by others. Where the client is a “domestic client”, as defined in the regulations, some of their duties may be undertaken by the Principal Designer or Principal Contractor, but the overall responsibility for them remains with the client.

Will the client, Principal Designer and Principal Contractor be liable to criminal prosecution as a result of any CDM failures?

The primary legislation behind the CDM 2015 is the Health and Safety at Work, etc Act 1974. Failure to comply with this legislation is an offence under the criminal conviction.

Changes to the Enterprise and Regulatory Reform Act which came into effect in 2013 mean that the CDM 2015 no longer give rise to civil liability, so the main course of action will be through the criminal courts. Prosecution under this legislation can mean an unlimited fine and/or two years’ imprisonment.

It is common for companies to be prosecuted for breaches of health and safety, but this can be extended to directors and other employees where it can be shown that the breach has been caused by their negligence.


The CDM 2015 have been in force in the UK for more than 25 years. Even taking into account the fact that there has been three different versions in that time, their application is not at all as well understood as you would hope. As the main purpose of CDM is to ensure the management and co-ordination of health and safety activities on a construction project, perhaps it is time that we all reviewed the guidance once more.

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