8th May, 2025

The Definition Of Construction Work Under CDM 2015

If you work in construction, you have probably heard of the CDM Regulations. Because the Construction (Design and Management) Regulations (CDM 2015) apply to all construction projects. But what exactly is construction work? Let's look at the definition of construction work under CDM.

The Definition Of Construction Work Under CDM 2015 header image

The Construction (Design and Management) Regulations (CDM) apply to all construction work. But what is construction work?

Building a house? Yes. Knocking down a wall? Yes. But what about painting a wall, digging a hole, or fitting some windows?

The definition of construction work covers more than you might think under CDM.

Let's take a look.

What is construction work under CDM 2015?

It's important to be aware that CDM applies to construction work and not just construction projects. It doesn't matter how short or small the work is, or if it involves one person, or one hundred people, if it's classed as construction work, CDM applies.

The definition of construction work under CDM 2015 is far-reaching. If you work in construction or engage with contractors, chances are, anything you do will attract the CDM regulations.

You might expect CDM to cover a big extension or refurbishment project. But what about installing a new service? Carrying out maintenance on your heating? Replacing parts? Or giving your office a new lick of paint?

For details on what exactly is classed as construction work under CDM, we can take a look at the regulations themselves - because the CDM regulations tell us what construction work is - useful!

The definition of construction work under CDM is split into 5 parts, so there's quite a bit to cover. Let's start with part a) below.

building a wall

Definition part a)

'construction work' means the carrying out of any building, civil engineering or engineering construction work and includes—

  1. 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), de-commissioning, demolition or dismantling of a structure;
The Construction (Design and Management) Regulations 2015 Interpretation

Some of the examples given are fairly obvious - construction, alterations, repair, demolition. Yes, we would expect CDM to apply to these activities. They are classic examples of construction work.

But what about cleaning?!

Yes, while you might not see cleaning as construction work, cleaning with high-pressure water or toxic substances is also covered under the definition of construction work in CDM 2015.

Renovation, repairs, upkeep, redecoration, and other maintenance jobs are also classed as construction work where CDM applies.

Definition part b)

  1. the preparation for an intended structure, including site clearance, exploration, investigation (but not site survey) and excavation (but not pre-construction archaeological investigations), and the clearance or preparation of the site or structure for use or occupation at its conclusion;
The Construction (Design and Management) Regulations 2015 Interpretation

It's not just the work on a structure that attracts the CDM regulations, but also the preparation for that work. Clearing the site, excavating for services, site investigations - all the things you might do to prepare a site ready to build. CDM 2015 applies here too.

cranes on a construction project

Definition part c)

  1. the assembly on site of prefabricated elements to form a structure or the disassembly on site of the prefabricated elements which, immediately before such disassembly, formed a structure;
The Construction (Design and Management) Regulations 2015 Interpretation

Considering that a structure covers anything from a building to pipework, earthworks and scaffolding, the assembly of any elements to form a structure of any kind is classed as construction work. And also the disassembly.

Prefabrication of elements in construction is becoming increasingly popular due to the speed and cost (and often safety) benefits, but it's still important to apply CDM to this type of work.

Definition part d)

  1. the removal of a structure, or of any product or waste resulting from demolition or dismantling of a structure, or from disassembly of prefabricated elements which immediately before such disassembly formed such a structure;
The Construction (Design and Management) Regulations 2015 Interpretation

So the removal of a structure and also the removal of any waste from the demolition of a structure falls under the definition of construction work. You might think there is some repetition here regarding disassembly, but where section c) covers disassembly of the prefabricated elements, section d) covers the removal once disassembled.

CDM applies to all demolition work, removal of structures, and dismantling of structures, including the removal of demolition waste.

electrician installing a socket

Definition part e)

  1. the installation, commissioning, maintenance, repair or removal of mechanical, electrical, gas, compressed air, hydraulic, telecommunications, computer or similar services which are normally fixed within or to a structure.
The Construction (Design and Management) Regulations 2015 Interpretation

Work on fixed services within a building or structure also comes under the definition of construction work under CDM.

This usually doesn't come as a surprise to electricians and plumbers who are working on construction sites. Electricians and plumbers are often aware of CDM and expect to apply CDM to their work on a building project.

But CDM should also be applied when carrying out repair and maintenance work on those systems. And even if an electrician or plumber is doing the work alone, like repairing a leak or adding a socket, and not as part of a larger construction project, CDM still applies for only one contractor. Even if it's a short or small amount of work. CDM applies no matter the size or duration.

And it's not just electrical work and plumbing work. It's other services too. Like telecommunications and computer services. So anyone installing computer, telephone, or similar systems should also be aware that their work is defined as construction work in CDM 2015.


As you can see, construction work covers more than just your new build and refurbishment projects under CDM. And the definition of construction work covers quite a wide range of activities.

If you need help with CDM, you can use our free CDM duty holder guides and check how your project is doing with the CDM compliance checklist.

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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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