CDM 2015 Duties Explained for Small Contractors

CDM 2015 applies to every construction project in the UK, not just the big notifiable ones, and it hands small contractors real legal duties whether they realise it or not. The Construction (Design and Management) Regulations 2015 set out who is responsible for managing health and safety risk at every stage of a build, from a single tradesperson doing a domestic extension to a full site team. If you're a small contractor and you've assumed CDM only applies to large sites with a principal contractor sign on the gate, that assumption is the most common and most costly mistake in the trade.

Who counts as what under CDM 2015

The regulations define five duty holders: client, principal designer, principal contractor, designer and contractor. On a small job with only one contractor involved, that contractor takes on the contractor duties directly, which means planning, managing and monitoring the work under their control, and making sure workers are competent and adequately supervised. As soon as a project involves more than one contractor at any point, a principal contractor and principal designer must be appointed, and for many small building firms that principal contractor role often falls to them by default, whether it was formally agreed or not.

What a small contractor actually has to do

In practice this comes down to a handful of concrete duties. You need to plan, manage and monitor your own work so it's carried out without risk to health and safety, as far as is reasonably practicable. You need to check that anyone you employ or bring onto the job has the right skills, knowledge, training and experience for the work. You need to provide the right information, instruction, training and supervision. And you need to make sure welfare facilities are in place for the duration of the work, which is a duty that gets missed surprisingly often on small domestic jobs where there's an assumption the client's toilet counts.

Domestic clients and CDM

A common misunderstanding is that CDM doesn't apply on domestic projects. It does, but the duties that would normally sit with the client are passed to whichever party is best placed to carry them, usually the principal designer if one is appointed, or the principal contractor if there is no principal designer, or the contractor if there's only one contractor on the job. Homeowners are not expected to understand CDM, so the regulations move their client duties onto the professionals actually running the project.

When a project becomes notifiable

Most small jobs never reach this threshold, but it's worth knowing where it sits. A project is notifiable to the HSE if the construction work is expected to last longer than 30 working days and have more than 20 workers on site at the same time at any point, or if it exceeds 500 person days of work. Below that, CDM still applies in full, there's simply no requirement to notify the HSE using an F10 form.

Getting the paperwork right underneath all of this usually comes down to having a proper construction phase plan and method statements that actually reflect the job, rather than a generic document pulled off a template site. It's worth understanding what a risk assessment and method statement is actually meant to cover, since RAMS paperwork is one of the first things checked when a CDM duty holder is asked to prove they've managed the risk properly. It's also worth getting the structure right, since a method statement that actually passes review needs to match the real sequence of work, not a copy-pasted version from a different job.

If you're taking on contractor or principal contractor duties under CDM 2015 and need paperwork that would genuinely hold up if the HSE asked to see it, that's exactly what I do. I write professional RAMS and method statements for UK construction sites, built around the actual job rather than a generic template.