Construction Phase Plans — What CDM 2015 Means for Small Trade Jobs (2026)

What CDM 2015 Actually Requires

CDM 2015 is the main set of health and safety regulations covering construction work in Great Britain. It applies to all construction projects, from a multi-million-pound development down to a single-trade domestic job. Its purpose is simple: to make sure health and safety is planned, managed and coordinated throughout a project, by the people best placed to control the risks.

One of the core requirements of CDM 2015 is that a Construction Phase Plan (CPP) is drawn up before construction work begins. The plan sets out the health and safety arrangements, site rules and specific measures for managing the significant risks on that particular job. It's not a generic policy document — it's a practical plan for the actual work in front of you.

Yes — Even a Single Domestic Job Needs One

This is the single most common misconception in the trades, so it's worth being blunt: a Construction Phase Plan is required for every construction project, not just large or notifiable ones. There is no exemption for small jobs, domestic jobs or single-contractor jobs. If you're fitting a kitchen, building an extension, replacing a roof or rewiring a house, a CPP is required before work starts.

What changes with the size and complexity of the job is not whether you need a plan, but how detailed it has to be. The regulations require the plan to be proportionate. For a small, low-risk job, a short, focused document covering the few significant risks is perfectly acceptable — and arguably better than a 40-page template padded with irrelevant content. The Health and Safety Executive (HSE) explicitly supports a proportionate approach, and even publishes a simple CPP template aimed at smaller domestic-style projects.

Who Has to Write the Construction Phase Plan?

Responsibility depends on how many contractors are involved in the project.

Single-contractor jobs

If you're the only contractor on the job — for example, a builder doing a small extension with their own team, no separate electrician or plumber engaged directly by the client — then you, as the contractor, must draw up the Construction Phase Plan. There's no principal contractor on a single-contractor project, so the duty falls to you.

Projects with more than one contractor

Where more than one contractor is involved — which covers a large share of real-world jobs, because a main builder plus a separately appointed electrician already counts as two contractors — the client must appoint a principal contractor and a principal designer in writing. The principal contractor is then responsible for drawing up and updating the Construction Phase Plan and coordinating the work of all the contractors on site.

If the client doesn't make that appointment, the duties of the principal contractor automatically fall to the contractor in control of the construction phase. In practice, that's usually the main builder — so on multi-trade jobs you may end up holding the CPP responsibility whether or not anyone formally handed it to you.

What a Proportionate Construction Phase Plan Must Contain

CDM 2015 doesn't prescribe a rigid format, but it does set out what the plan must cover. For a typical small job, you can capture all of it on a couple of sides of A4. The plan must record:

• A description of the project: what the work is, where it is, key dates, and the names and roles of the client, designer(s) and contractor(s) involved.
• The management of the work: the health and safety arrangements — who is in charge, how the work will be supervised, how contractors will be coordinated and how the workforce will be consulted.
• Site rules: the practical rules for the site, such as access arrangements, parking, deliveries, welfare facilities, permits to work, and rules for keeping other people (including the client and public) safe.
• The significant risks and how they're controlled: the specific health and safety risks for this job — for example working at height, asbestos, electrical isolation, excavations, hot works or manual handling — and the control measures for each. Generic hazards everyone knows about don't belong here; focus on what's significant for the actual work.

The plan should be readable by the people who need to use it. A document so long that nobody on site ever opens it fails the basic test of being a usable plan. Keep it specific, keep it short, and update it if the work or the risks change.

Domestic Clients vs Commercial Clients

CDM 2015 splits clients into two categories, and the difference matters for where the duties land.

A domestic client is someone having construction work done on their own home (or the home of a family member) that isn't connected with a business. Domestic clients have client duties under CDM 2015, but in almost all cases those duties are automatically passed to the contractor — or, on a multi-contractor job, to the principal contractor. In other words, the homeowner doesn't have to manage CDM compliance; the trade does. So when you take on domestic work, you're effectively carrying the client's duties as well as your own, and the CPP responsibility sits firmly with you.

A commercial client — anyone having construction work done as part of a business, including landlords and property developers — keeps their client duties. They must make suitable arrangements for managing the project, provide pre-construction information, appoint the principal designer and principal contractor in writing on multi-contractor jobs, and ensure a Construction Phase Plan is prepared before work starts. The contractor or principal contractor still writes the plan, but the commercial client has a clear legal duty to make sure it happens.

When You Also Need to Notify the HSE (Form F10)

A Construction Phase Plan is required on every job. Notifying the HSE is a separate, additional requirement that only applies to larger projects. A project is notifiable — meaning you must submit form F10 to the HSE before construction starts — if the construction work is scheduled to:

• last longer than 30 working days and have more than 20 workers working simultaneously at any point; or
• exceed 500 person-days of construction work.

On a notifiable project the client makes the notification (on a domestic job, that duty passes to the contractor or principal contractor in the usual way). The vast majority of small trade jobs fall well below these thresholds, so they need a CPP but do not need to be notified. Don't confuse the two: many small contractors wrongly assume that because their job isn't notifiable, they don't need a plan. The plan is always required; the F10 only applies to the big ones.

Quick Reference: CPP Responsibility and HSE Notification

Practical Tips to Keep It Simple

The goal is a plan that genuinely helps you run the job safely, not a box-ticking exercise. For typical small jobs:

• Use the HSE's short template. The HSE publishes a free, simple CPP template aimed at smaller projects. Start from that rather than a bloated commercial template — it keeps you proportionate by design.
• Write it for the specific job. Swap out the project description, dates and significant risks for each new job. A reused plan that still references a different address or different work is worse than useless.
• Only list significant risks. If a risk is obvious and trivial, leave it out. Concentrate on the few things that could seriously hurt someone — working at height, electrics, asbestos, excavations — and the controls you'll actually use.
• Keep it to a page or two for small jobs. Proportionate means short. A focused two-page plan that the whole team reads beats a thick document nobody opens.
• Have it ready before work starts. The plan must exist before the construction phase begins, not be written up afterwards. Produce it as part of your job setup, alongside the quote and any risk assessments.
• Update it if things change. If the scope grows, a new risk appears or another contractor joins, revise the plan. It's a living document for the life of the project.
• Keep a copy on file. Store the signed plan with your job records. If there's ever an incident or an HSE inspection, being able to produce a job-specific CPP demonstrates you took your duties seriously.

The Bottom Line for Small Trades

A Construction Phase Plan is a legal requirement on every construction project you run, including small domestic jobs — there is no exemption for being small. On a single-contractor job you write it; where more than one contractor is involved, the principal contractor does. Domestic clients pass their CDM duties to you, while commercial clients keep theirs. HSE notification via form F10 is a separate matter that only kicks in on the larger projects over the 30-day/20-worker or 500-person-day thresholds.

Get into the habit of producing a short, job-specific plan as part of your standard setup, and CDM 2015 compliance stops being a worry and becomes a routine part of running professional, well-organised trade work.