The 3 Stages Of CDM (From Pre-Construction To Post-Construction)

According to the CDM Regulations, there are three stages to every construction project. Pre-Construction. Construction. And Post-Construction. And there are CDM duties to complete at each stage of the project.

Things you need to do before work starts on site. Then things that need to happen during construction. And finally, things that need to take place after work is completed.

If you're new to construction, or the CDM regulations, start with what is CDM in construction?

So let's take a look at the 3 stages of CDM:

1. Pre-construction
2. Construction
3. Post-construction

What is pre-construction?

When you imagine construction work, you might think of all the things happening on site. Machinery, excavations, new structures etc. But so much work goes into a construction project before you can start building (or demolishing) anything.

Pre-construction is everything that happens on a construction project before you do any construction work. You might refer to this as the planning phase or project preparation, but in CDM, it's known as the pre-construction phase.

“pre-construction phase” means any period of time during which design or preparatory work is carried out for a project and may continue during the construction phase;

But if the CDM regulations are focused on health and safety in construction, then that would just apply to the construction phase, right? Isn't the pre-construction phase mainly office-based? What does the pre-construction phase have to do with health and safety?

Quite a lot, as it happens!

As with most things, with health and safety, preparation is key. This is especially important in construction where you are bringing different people together, on a new site, with various hazards and risks.

Each build and site is unique, and careful consideration of how the health and safety issues can be minimised during the pre-construction phase is vital to reduce health and safety headaches during construction.

This is why the CDM regulations pay so much attention to the pre-construction phase. Clients have duties in the pre-construction phase. Designers have duties in the pre-construction phase. Contractors have duties in the pre-construction phase. And the pre-construction phase is when the principal designer and the principal contractor are appointed too.

If you want to comply with CDM (and have a safe and successful construction project), you can't skimp on the pre-construction phase.

The regulations clearly state that the client must allow enough time for the work to be carried out without risks to health and safety. It's one of the legal CDM client duties. This includes allowing sufficient time for all of the pre-construction duties to be carried out, like making appointments, carrying out design work, preparing the pre-construction information and the construction phase plan.

The principal designer has overall responsibility for health and safety during the pre-construction phase, and other duty holders will work with them to comply with CDM.

Want to know more about your duties in the pre-construction phase? Read our free duty holder CDM guides.

What is the construction phase?

The construction phase is the time when construction work is actually happening on your site.

At this point in the project, you have your designs and plan of work, your construction phase plan in place and your team assembled. Everything is planned out, at least for the early stages of your project.

“construction phase” means the period of time beginning when construction work in a project starts and ending when construction work in that project is completed;

This is the point in the project that you might think CDM really kicks in, but actually, most of the CDM duties should already be discharged by now, during the pre-construction phase. By the time you start the construction phase, the principal contractor has already been appointed and the construction phase plan has been developed.

But while the plans have already been made, now is the time in the project when all that planning and preparation is put into practice.

Important duties continue into the construction phase like organising contractors and coordinating their work, communication between duty holders if plans change or issues arise, securing the site and making sure that those on the site have had suitable site inductions and are safe to work.

This stage of the project is when you will need to comply with the less talked about Part 4 of the CDM regulations.

The principal contractor has overall responsibility for health and safety during the construction phase, and other duty holders will work with them to comply with CDM.

Want to know more about your duties in the construction phase? Read our free duty holder CDM guides.

What is post-construction?

There's no specific definition (or even mention) of post-construction in the CDM regulations. However, there are duties that must be carried out at or after project completion, so we refer to this as the post-construction phase.

Health and safety risks don't stop when the work is finished on your site.

Now the project is complete, people will start to use the structure and the equipment installed. People will need to clean and maintain it. Eventually, it may need to be altered or demolished. There could be many health and safety risks in the future use of the structure. CDM acknowledges this, by requiring this health and safety information to be passed on to the client in what is known as the CDM health and safety file.

(10) At the end of the project, the principal designer, or where there is no principal designer the principal contractor, must pass the health and safety file to the client.

(7) If a client disposes of the client’s interest in the structure, the client complies with the duty in paragraph (5)(b)(iii) by providing the health and safety file to the person who acquires the client’s interest in the structure and ensuring that that person is aware of the nature and purpose of the file.

So at project completion, the health and safety file needs to be given to the client. This file should be kept by the client so that anyone carrying out future work will have the information they need to be able to plan and complete the work safely.

Want to know more about your duties in the post-construction phase? Read our free duty holder CDM guides.

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