CDM Regulations vs Building Regulations: What Is the Difference?

A practical guide for UK site managers, contractors and small builders.

The phrase CDM building regulations gets typed into search every day, and it hides a genuine confusion: people assume the CDM regulations and the building regulations are one and the same, or that meeting one covers the other. They do not, and it does not. They are two separate bodies of law that both apply to construction work but govern completely different things. This guide sets out what each one covers, when each applies, who enforces them, and how they run alongside each other on a real project.

Are CDM regulations and building regulations the same thing?

No. They are two distinct legal regimes with different purposes, different enforcers and different tests for when they apply. In short, the CDM regulations are about how the work is managed safely, and the building regulations are about whether the finished building itself is up to standard. You can comply fully with one and still be in breach of the other, so both have to be handled on their own terms.

What the CDM regulations cover

The Construction (Design and Management) Regulations 2015, universally shortened to CDM 2015, are health and safety law. They set out how a construction project must be planned, managed and coordinated so that the people building, using, maintaining and eventually demolishing a structure are not put at risk.

CDM works by assigning duties to the people involved, known as duty holders: the client, the principal designer, designers, the principal contractor, contractors and workers. It covers things like appointing the right people, gathering and sharing pre-construction information, producing a construction phase plan, managing site risks and providing welfare facilities. It is concerned with the process of building, not the technical specification of the building.

What the building regulations cover

The building regulations are a separate set of rules that govern the technical standards of the building work itself. They exist to make sure the finished structure is safe, healthy, accessible and reasonably efficient to run. In England the standards are grouped into a series of Approved Documents covering areas such as structural stability, fire safety, ventilation, drainage, energy performance, sound insulation and access.

Where CDM asks how safely the job is run, the building regulations ask whether the wall, the staircase, the beam, the insulation and the fire escape actually meet the required standard. They are about the physical result, judged against a technical benchmark, rather than the way the site was managed.

When each one applies

The triggers are different, and this is where a lot of the confusion starts.

• CDM 2015 applies to all construction work. There is no minimum size. A single-contractor kitchen refit and a multi-contractor commercial build both fall under CDM, whether or not the project is notifiable to the HSE.
• The building regulations apply to building work as they define it. That typically means new buildings, extensions, material alterations, controlled services such as heating or electrics, and certain changes of use. Some minor works are exempt, and repairs on a like-for-like basis often fall outside them.

The practical upshot is that almost any construction project engages CDM, while the building regulations bite whenever the work meets their definition of building work. On most jobs of any size, both apply at once.

Who enforces them

The two regimes are policed by different bodies, which is another reason they are best kept separate in your head.

• CDM 2015 is enforced mainly by the Health and Safety Executive, with local authorities enforcing in some sectors. Breaches are health and safety offences.
• The building regulations are enforced through building control, provided either by the local authority or by a registered building control approver. Compliance is checked through the building control process and sign-off.

How they work together on a project

On a live job the two regimes run in parallel from start to finish, and neither one excuses the other. A construction phase plan that satisfies CDM says nothing about whether your steelwork meets the structural standard; a building control sign-off says nothing about whether the site was run safely while that steel went in. Good practice is to treat them as two separate checklists that happen to sit on the same project: manage the work to CDM, build to the building regulations, and keep the evidence for each. Handled that way, the overlap stops being confusing and simply becomes two boxes that both get ticked.

Frequently asked questions

This article is general guidance for UK construction and is not legal advice. For requirements specific to your work, check the full text of CDM 2015 and current HSE guidance, including L153, along with the building regulations and Approved Documents that apply to your project.