CDM 2015 construction phase plan: what must be in place before work starts

A construction phase plan is not a document a principal contractor writes once work has already started and backfills to look tidy. Under the Construction (Design and Management) Regulations 2015 (CDM 2015, SI 2015/51), the plan has to exist, in a form suitable for the project, before the first operative sets foot on site. Most principal contractors know this in principle. On the sites we look at, the plan that was supposedly in place on day one is often a generic document nobody has read, sitting behind the real set of arrangements the site team actually worked to. This post is about what regulation 12 and regulation 13 require, and the gap between having a plan and having the right one in place before work starts.

Where the duty sits

CDM 2015 places the plan itself squarely with the principal contractor. Regulation 12 is the duty to draw up a construction phase plan, and then to implement it and keep it reviewed and revised as the project moves, rather than treating it as fixed on day one. The same regulation carries the client's side of the bargain: the client must not allow the construction phase to start until a suitable plan is in place and the welfare facilities a project needs are arranged. That is the mechanism that makes "before work starts" a legal gate rather than a target. If the plan is not ready, the client should not be letting the principal contractor mobilise, whatever the programme says.

Regulation 13 then covers what the principal contractor has to do with the plan once the phase begins: plan, manage, monitor and coordinate construction work for the whole of that phase, not just write a document and move on. That includes making sure every contractor on site has been given the site induction and the parts of the plan relevant to their work, keeping unauthorised people off site, and seeing that contractors cooperate and coordinate with each other rather than working to separate, unreconciled plans of their own. Welfare facilities have to be in place for the whole of the construction phase, not just available to inspect on the first morning.

Our records show CDM 2015 unchanged since its last consolidating amendment, dated 1 January 2018 on the legislation.gov.uk record, with no outstanding effects as at our last check. HSE's own guidance on the regulations is set out in L153, Managing health and safety in construction, which is the document most principal contractors and inspectors measure a plan against in practice.

What the plan has to show

CDM 2015 does not ask for a fixed-length document; it asks for a plan proportionate to the risk on the project, and in practice reviewers and inspectors look for the same handful of things whatever the size of job. A description of the project and the work involved. The management structure for the construction phase: who is in charge, who deputises, and how contractors report into it. The site rules, and how they will be communicated and enforced, not just listed. The arrangements for worker consultation and engagement, so the workforce has a route to raise a concern. Welfare facilities and where they sit on site. The arrangements for site security and for controlling who can get in. And, specific to the risks the project actually carries: traffic and pedestrian routes, work near existing services, storage and use of hazardous substances, the stability of structures during the works, and the emergency and fire procedures that apply.

The common failure is not a missing section. It is a plan that copies all of this in generic language from a template and never gets reworked against the actual site: a traffic management paragraph that does not name the gate the project is using, an emergency procedure that gives a muster point that does not exist on this site, a site rules section that reads the same on every job the company runs. A reviewer who has seen a hundred of these spots a generic plan in the first page, and an inspector asking a site manager to point to the muster point named in the plan finds out fast whether it was ever read.

Before work starts: the test that actually matters

"Before work starts" is tested less by the date on the plan's cover sheet than by what can be shown to have happened before the first operative arrived. Three things in particular:

• The plan was issued, not just drafted. A dated record of the plan being issued to the client, the principal designer where one is appointed, and the contractors due to start, ahead of mobilisation.
• Welfare was arranged, not promised. Toilets, washing and rest facilities ordered and installed, or a written arrangement for interim facilities, before the first shift, not scheduled for "week two" once the compound is finished.
• The site induction was built around this plan, not a stock one. An induction record naming the project-specific rules, hazards and emergency arrangements the plan describes, delivered to every contractor before they started work, with signatures and a date that precedes the work, not follows it.

Any of these missing is a plan that existed on paper on day one and in practice some days or weeks later. Most disputes about whether CDM 2015 was complied with on a given site turn on exactly this gap.

Where it slips after the start

Regulation 12's review duty is often the weakest part of the file. A plan written for the mobilisation stage, covering groundworks and enabling works, is rarely revisited once the project moves into structure, fit-out or commissioning, even though the significant risks, the contractors on site and the site rules have all changed by then. We see three recurring patterns:

1. The plan is reviewed on a fixed date in the programme rather than against a trigger, so a new high-risk activity starting mid-project, a new subcontractor with its own plant, or a change in site layout, goes unreflected for months.
2. Later contractors are given the original issue of the plan and the original induction, because document control was never told a revision had happened.
3. The health and safety file information the principal contractor owes the principal designer under regulation 12 is left to the last fortnight of the project, when the people who actually did the relevant work have mostly left site.

The record that proves it was in place in time

When a plan's timing is challenged, by an inspector, an auditor or a client, the file has to answer from dated records rather than a manager's recollection.

A site that can produce all four inside a few minutes has a plan that was genuinely in place, not one that merely existed. A site that cannot is relying on the plan having been correct in principle and hoping nobody asks when.

What we would put in place before the next mobilisation

Three things cover most of the gap we find. Build the construction phase plan against this project's traffic routes, services, rules and emergency arrangements rather than a previous one, even where the structure of the document is reused. Tie the plan's review to events on the programme, not a calendar date, so a genuine change in risk triggers a revision. And make the site induction the moment the plan actually reaches the workforce, with a record that ties the two together. Our construction phase plan template is built to regulation 12 with a worked example completed end to end, and the wider Site Management, Planning & Records Pack carries it alongside the daily records, inductions and registers that show the plan was followed once the work began, not just written before it.