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Jack Cameron


It’s been 9 years since the updated Construction Design Management (CDM) Regulations were unveiled to the construction industry, and completely reshaped the way we build our homes.

These regulations were created over 30 years ago by the Health and Safety Executive (HSE) of the British Government. The aim of this was to improve health and safety in the built environment and to protect all those involved in building projects.

AC Architects apply CDM to all our projects, and  always work to educate our clients on how these regulations will affect their projects. This article will explain how these regulations apply to your project, and who is responsible for ensuring that these regulations have been properly considered throughout the design and construction phases of your project.



If you are designing your dream home, extension or any kind of building for that matter, your Architect/Designer/Builder should be talking to you about CDM 2015 as a matter of importance. Understanding these regulations as a self-builder is vital to getting your project off the ground safely and succinctly.

Health & safety apply to your existing site conditions and buildings, the planning of your proposed design, its erection on site, its maintenance once completed and perhaps even its deconstruction. How will you keep yourself and those who work for you safe and healthy on your project?


The CDM 2015 Regulations place responsibility for managing the health and safety of a construction project on three main duty holders. The client has overall responsibility for the successful management of the project and is supported by the principal designer and principal contractor in different phases of the project.

The principal designer and principal contractor have an important role in coordinating health and safety. All three duty holders must have good working relationships from the outset if the project is to be delivered safely and without harm to health.

The Client ensures that the construction project is set up so that it is carried out from start to finish in a way that adequately controls the risks to the health and safety of those who may be affected. This is outlined in this handy Industry Guide for Clients. Clients can be broken down into two types. Have a think about which one you are:


  1. Commercial clients have construction work carried out as part of their business. This could be an individual, partnership or company and includes property developers and companies managing domestic properties.
  2. Domestic clients have construction work carried out for them but not in connection with any business, usually work done on their own home or the home of a family member.
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 The Principal Designer (PD) plans, manages and monitors health and safety in the pre-construction phase of a project. The role extends to the construction phase through the principal designer’s duties to liaise with the principal contractor.
Guidance on this expresses that the principal designer must have the technical knowledge of the construction industry relevant to the project, along with the skills, knowledge and experience to understand, manage and coordinate the pre-construction phase, including any design work carried out after the construction begins.


The Principal Contractor (PC) plans, manages and monitors the construction phase of a project. This involves liaising with the client and principal designer throughout the project, including during the pre-construction phase.


Guidance on this expresses that the Principal Contractor must have the skills, knowledge, experience and (if organisation) the organisational capability to carry out their role effectively given the scale and complexity of the project and the nature of the health and safety risks involved.



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Commercial clients must make suitable arrangements for managing their project including:


  • Appointing suitable duty holders to the project i.e. designers, contractors, principal designer (PD) and principal contractor (PC)
  • Allowing sufficient time and resources for each stage of the project
  • Making sure that the PD and PC carry out their duties in managing the project.
  • Making sure suitable welfare facilities are provided for the duration of the construction work.
  • Maintain and review the management arrangements for the duration of the project.
  • Provide pre-construction information to every designer and contractor either bidding for the work or already appointed to the project.
  • Ensure that the principal contractor or contractor (for single-contractor projects) prepares a construction phase plan before that phase begins.
  • Ensure that the principal designer prepares a health and safety file for the project and that it is revised as necessary and made available to anyone who needs it for subsequent work at the site.


CDM 2015 does not require domestic clients to carry out client duties as these normally pass to other duty holders:


  • If a single contractor project, then the Contractor must take on the legal duties of the client in addition to their own as contractor.
  • If more than one contractor, the PC must take on the legal duties of the client in addition to their own as PC. If the domestic client has not appointed a PC, the client’s duties must be carried out by the contractor in control of the construction work.
  • On a project with more than one contractor, where the client has appointed an architect (or another designer) they can ask them to manage the project and take on the client’s duties instead of the PC by way of a written agreement.

Any designer in charge of coordinating and managing a project is assumed to be the PD. Your Architect is likely to add CDM services as an extra fee on top of design work.

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The HSE must be told about your project, before work starts on-site if the following apply:

  • The construction work will last longer than 30 working days


  • Involves more than 20 workers at any one time


  • Where the work exceeds 500 individual worker days

This is set out as a duty for the client in a commercial project, the PC where the client is domestic or the PD where the client is domestic and has requested the PD takes on their duties. Notification is carried out by way of completing an F10, which can be found here. Once complete this form should be displayed in the construction site office.


“ CDM is a role that you as a self-builder can fulfil, just make sure you know what the regulations are and how you fulfil them."

- Jenny Chandela, US Registered Architect


Non-compliance with CDM 2015 is a criminal offence. We must highlight that if you proceed on-site without complying with CDM 2015 you are proceeding at your own risk. Whoever oversees design or construction work has liability. 

CDM 2015 was created to help guide you and as far as reasonably possible in reducing risks to the workers on your site. Any injuries/deaths on site as a result of not complying with the CDM health and safety process could result in a criminal record, fines and or prison time for the liable party. As a designer, we must ensure that both we and our clients are complying with CDM 2015 regulations before proceeding with work.

If you are a Commercial Client, complying with Client duties including appointing a Principal Designer and Principal Contractor is non-negotiable.


Domestic Clients, if you choose to take control of any part of your project at the pre-construction stage or construction stage you take on liability for that stage and you should ensure you are capable of doing so as well as complying with these regulations.

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Keeping up with regulations is what makes the difference between a good and bad client. As an Architectural practice, AC Architects endeavours to assist and advise our clients in finding the safest route forward for their projects.

We aim to get all the necessary information in order to, as far as reasonably possible, prevent anything untoward from happening during the construction phase of our client’s project or when the building is in use. If your project team are not talking to you about CDM, perhaps it’s worth setting up a meeting to discuss it.

Further reading of CDM and its implications can be found here.

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