CDM 2015 Regulations: What Small Contractors Need to Know

The Construction (Design and Management) Regulations 2015 — CDM 2015 — apply to every construction project in the UK. Not just large sites. Not just commercial work. Every project, including domestic work.

Most small contractors know CDM exists but assume it only applies to big sites with principal contractors and CDM coordinators. That's wrong. If you're a one-person roofing firm replacing tiles on a bungalow, CDM applies to you.

This guide explains what CDM 2015 actually requires from small contractors, what you need to do in practice, and where most people get it wrong.

What CDM 2015 covers

CDM 2015 is a set of health and safety regulations specific to construction work. It replaced the 2007 version and simplified the duty-holder structure.

It applies to all construction work in Great Britain, regardless of:

• Project size (no minimum threshold)
• Project value (no minimum cost)
• Project duration (no minimum time)
• Whether it's commercial or domestic

"Construction work" includes: building, alteration, fitting out, commissioning, renovation, repair, upkeep, redecoration, decommissioning, demolition, and dismantling of structures.

If you're a tradesperson doing any of the above, CDM applies.

The duty holders

CDM 2015 defines five duty holders. On a small project, one person may fill multiple roles.

When there's only one contractor

If you're the only contractor on a project (common for small domestic jobs), there's no principal designer or principal contractor. The client has basic duties and you — the sole contractor — have the contractor duties.

When there's more than one contractor

The moment a second contractor appears (e.g., you hire a subcontractor, or another trade is on site), the client must appoint a principal designer and a principal contractor. For small projects, the client often doesn't realise this — which means the duty falls on whoever is coordinating the work. Usually you.

What contractors must do

As a contractor under CDM 2015, you must:

Before work starts

1. Plan the work — identify health and safety risks and plan how to manage them
2. Check competence — ensure your workers (and any subcontractors) are competent for the work
3. Provide information — give workers relevant information about risks and how they're managed
4. Cooperate with others — if working alongside other contractors, cooperate on health and safety

During the work

5. Manage risks — implement the controls you planned
6. Provide welfare facilities — toilets, washing, rest areas, drinking water (on larger sites)
7. Monitor compliance — check that your health and safety measures are being followed
8. Report incidents — RIDDOR reporting for injuries, dangerous occurrences

On every project

9. RAMS — Risk Assessment and Method Statement. Not explicitly named in CDM 2015, but RAMS are how you demonstrate compliance with the requirement to plan, manage, and assess risks.

RAMS: the practical requirement

CDM 2015 requires you to plan and manage health and safety risks. In practice, this means producing RAMS for every job — especially commercial jobs.

A RAMS document covers:

• Risk Assessment — identify hazards, assess who could be harmed, evaluate the risk, record control measures
• Method Statement — step-by-step description of how the work will be done safely

When you need RAMS

• Commercial sites: Always. The principal contractor will require your RAMS before you set foot on site.
• Domestic work: Technically CDM applies, but most domestic clients don't ask for formal RAMS. Good practice to have them anyway — they protect you in a dispute.
• Working at height: Always, regardless of client type.
• Hot work: Always (welding, soldering, lead burning on roofs).
• Confined spaces: Always (drains, tanks, loft spaces with restricted access).
• Asbestos exposure: Always (any pre-2000 building).

Writing RAMS

Most small contractors hate writing RAMS. It's paperwork that feels like it adds nothing. But a RAMS document takes 15-30 minutes to produce and protects you from:

• HSE prosecution — if an incident occurs and you have no risk assessment, you're in serious trouble
• Client disputes — if a customer claims you damaged their property, your method statement shows what you planned to do
• Insurance claims — your insurer may refuse a claim if you can't evidence risk management

Muster generates RAMS using AI. Describe the job, and the system produces a risk assessment and method statement based on the work type, site conditions, and applicable regulations. Edit, approve, and attach to the job.

Construction Phase Plan

On projects with more than one contractor, the principal contractor must produce a Construction Phase Plan before the construction phase begins. This document covers:

• Description of the project
• Management arrangements
• Arrangements for controlling significant risks
• Welfare arrangements
• Health and safety file information

If you're a small contractor appointed as principal contractor (because you're coordinating the subcontractors), you're responsible for producing this. It's more comprehensive than a RAMS — it covers the entire project, not just your work.

Common mistakes by small contractors

1. "CDM doesn't apply to me — I'm too small"

Wrong. CDM applies to all construction work. There's no size threshold. A sole trader replacing a kitchen counts as construction work under CDM 2015.

2. "Domestic work is exempt"

Partially wrong. CDM 2015 applies to domestic work, but the client duties are relaxed. The client doesn't need to appoint a principal designer or principal contractor on domestic projects unless it's notifiable to the HSE (see below). Your contractor duties still apply in full.

3. "I don't need RAMS for small jobs"

Technically RAMS aren't specifically named in CDM 2015. But Regulation 15(2) says contractors must "plan, manage and monitor construction work" to ensure safety. A RAMS is how you evidence this. Without one, you're relying on verbal assertions that won't hold up in an HSE investigation.

4. "RAMS are just for the principal contractor to worry about"

No. Every contractor must manage their own health and safety. If you're a subcontractor, the principal contractor will require your RAMS. If you're the sole contractor, you should produce them for your own protection.

5. "F10 notification is only for big sites"

The HSE must be notified (via an F10 form) for projects that are:

• Longer than 30 working days AND have more than 20 workers at any one time, OR
• Exceed 500 person-days

Many small contractors hit these thresholds without realising it. A domestic extension with 4 tradespeople working for 8 weeks is 160 person-days. A re-roof with 3 people for 12 weeks could hit 180 person-days.

What happens if you don't comply

HSE enforcement

The Health and Safety Executive can:

• Issue improvement notices (fix the problem within a deadline)
• Issue prohibition notices (stop work immediately)
• Prosecute (criminal offence, unlimited fines)
• Imprison (for serious breaches causing death or injury — directors can be personally liable)

Insurance implications

If an incident occurs and you can't evidence CDM compliance:

• Your insurer may reduce or refuse the claim
• Your premium will increase significantly at renewal
• You may struggle to get insurance at all from specialist trade insurers

Client consequences

Commercial clients who discover you're not CDM-compliant during a project can:

• Remove you from site
• Withhold payment
• Claim against you for delays caused by non-compliance
• Blacklist you from future work

The practical checklist

For every job:

• Identify the duty holder structure (are you the sole contractor or one of many?)
• Produce a risk assessment (or full RAMS for commercial work)
• Check competence of your workers and any subcontractors
• Verify welfare facilities are available on site
• Check if the project is notifiable to the HSE (F10)
• Cooperate with other contractors on site
• Keep records of all the above

The bottom line

CDM 2015 isn't bureaucracy for its own sake. It's a legal framework that requires you to think about safety before you start work, manage risks during the work, and keep records of what you did.

For small contractors, compliance is straightforward:

1. Produce RAMS for every job
2. Check your workers are competent
3. Cooperate with other contractors on site
4. Keep records

The contractors who get caught out are the ones who assume CDM doesn't apply to them. It does. The fine for non-compliance is unlimited. The time to produce a RAMS is 15 minutes.