Construction Phase Plan: What to Include Under CDM 2015

11 August 2026

The Rule That Catches Experienced Builders Out

Every construction project needs a construction phase plan. Every single one. The loft conversion in Stockport, the two-day bathroom strip-out, the 40-week distribution centre. CDM 2015 draws no line between domestic and commercial clients here, and none between notifiable and non-notifiable work.

Notification is where most people go wrong. A project needs an F10 notification when construction work lasts longer than 30 working days with more than 20 workers on site at once, or exceeds 500 person-days. That threshold decides whether you send a form to the HSE. It has no bearing on whether you need a plan. You need one anyway.

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Plenty of builders still believe small domestic jobs are exempt. They are not. Fit a kitchen for a homeowner over a week and the law expects a plan before you start. Proportionate to the job, certainly. But it must exist.

Who Writes It, and When

The duty sits with the principal contractor. Regulation 12 of CDM 2015 requires the principal contractor to draw up the plan during the pre-construction phase, and where only one contractor is on the project, Regulation 15(5) puts the same duty on that contractor. Regulation 4(5) adds the client's side: they must ensure the plan is drawn up before the construction phase begins. On a domestic job where the client makes no appointments, the contractor in control of the work picks these duties up by default. If those role names are fuzzy, there is a role-by-role breakdown in CDM 2015 duty holders.

"Before the construction phase begins" means before the site is set up. Before the welfare unit is delivered, since welfare is one of the things the plan describes. A plan dated the same week as the groundworks tells its own story.

Your raw material is the pre-construction information from the client or principal designer: asbestos surveys, service drawings, structural information, site constraints. If nobody has sent you any, ask. Writing the plan is harder after someone finds the live cable with an excavator bucket. While you are gathering paper, the document checklist will tell you what else a project of your size needs in the folder before anyone signs in.

What to Include in a Construction Phase Plan

There is no prescribed format. HSE's CDM guidance lists topics to cover where they apply, and the sections below are what assessors expect to find. Keep each one specific to the job in front of you.

Project Description and Key Dates

The address, the client, the scope of work, the start date and the expected duration. Name the principal designer if one is appointed. Summarise the programme by phase: demolition, groundworks, frame, fit-out, whatever applies. Anyone picking the plan up cold should know within a page what is being built and how long it will take.

Management Structure and Responsibilities

Who runs the site day to day, and who they answer to. Name the site manager and their qualifications (an SMSTS ticket is the usual benchmark) and the supervisors under them. Say who deputises when the site manager is on leave. Set out how subcontractors are vetted and monitored, and how design information reaches the people doing the work. On a small job this section can be three sentences. Write them anyway.

Site Rules and Induction Arrangements

The rules everyone on site follows: sign-in at the gate, minimum PPE, permitted hours, traffic and pedestrian routes, delivery arrangements, 110v tools only, permits for hot works and excavations. Then describe how inductions are delivered and how they are recorded. An induction register the plan promises but nobody keeps proves the plan was never followed.

Welfare Arrangements

CDM 2015 requires welfare facilities from the first day of the construction phase, not from whenever the cabins turn up. State what is provided and where: toilets, washing facilities with warm water, drinking water, somewhere dry to rest and eat, storage for clothing. On a domestic job that might be agreed use of the client's toilet and kettle. Fine, if it is genuinely agreed. Write it down.

Risk Controls for the Job's Actual Hazards

The heart of the plan, and the section that exposes a copied template fastest. Identify the significant hazards on this project and summarise the control for each: the asbestos flagged in the refurbishment survey, the supply staying live for the occupied floors, the scaffold over the footpath, the deep drainage runs. Task-level detail belongs in the site risk assessments and each trade's RAMS, so the plan should explain how those documents get produced and briefed rather than duplicating their content.

Emergency Procedures

The fire plan and assembly point, how the alarm is raised, first aid provision and who holds it, the nearest A&E, and the arrangements for getting an injured person down from height. Include how accidents and dangerous occurrences get reported. This part of the plan has to work at 07:45 on a wet Tuesday with nobody senior on site, so keep it short and pin it up in the welfare unit.

Monitoring and Review

How you will check the plan is being followed: site inspections and their frequency, statutory checks (the Work at Height Regulations put scaffolds on a 7-day inspection cycle), toolbox talks, and how the plan itself gets reviewed as the job changes. Without a review mechanism the plan carries on describing week one long after the site has moved to week ten.

Keep the Plan Proportionate

HSE guidance is blunt on this point: the plan should match the scale and risk of the work, and paperwork that does nothing for health and safety is effort wasted.

For a two-day domestic extension, a few pages is enough. HSE's small-project guidance, CIS80, includes a simple template aimed at what it calls the busy builder, and CITB's free CDM Wizard app builds a small-job plan from your answers to a few questions. Either is acceptable, provided the answers describe your site rather than a hypothetical one.

A 40-week commercial job is a different document: phasing drawings, a traffic management plan, a temporary works register, lifting arrangements, interfaces between a dozen subcontractors, and a review schedule that survives staff changes. Forty pages might be genuinely proportionate there. Padding never is. Generic policy text buries the site-specific content an inspector actually wants.

Where Plans Come Unstuck

SSIP assessors and HSE inspectors see the same handful of problems on repeat:

The wrong site. A copied template still naming the previous project, or a postcode two counties away. Assessors spot it on page one and stop reading. It happens constantly.
A plan written after work started. Document dates that post-date the site set-up, or a plan quietly produced the week before an audit. Version histories give this away every time.
Welfare fiction. A plan describing a drying room and a canteen on a site that has a portaloo and a van. If the facilities on the ground do not match the section, an inspector will wonder what else in the document is aspirational.
Generic hazards, missing real ones. An asbestos paragraph on a new build, and nothing about the school entrance ten metres from the gate.
No named people. "The site manager" throughout, with no way to tell who actually holds the duty this week.

Review Triggers During the Build

The plan you write before set-up describes a site that does not exist yet. Once work starts, keep it honest. Review and update it when:

A design change alters the sequence or the temporary works
A new trade arrives whose work the plan never anticipated, like the piling rig nobody mentioned in March
An incident or near miss shows a control is not working
The site layout changes, say a tower crane goes up or a phase is handed over
The programme slips and takes the roof works into winter

Date each revision and keep the superseded versions, then brief the changes at the next induction or toolbox talk. By handover the plan should be scruffy with amendments, because a copy that still matches the day-one version has been describing an imaginary site since the first design change. Both the current version and the superseded ones can live in ComplianceVault with an audit trail of who changed what.