CDM 2015
Construction phase plan support
A construction phase plan is required before construction work starts and has to be kept current as the work changes. The common failing is not a missing plan, it is a plan written at mobilisation and never revisited while the site moves on weekly. Aldbry compiles the plan from your own material and flags where it has drifted from the packs actually in circulation. The duty stays with the dutyholder.
What the plan has to carry
A live document, not a mobilisation artefact
CDM 2015 does not prescribe a format. It expects the plan to reflect how the work is being managed now.
01
The arrangements for managing the work
How the construction phase is planned, managed and monitored, in enough detail that somebody could check you are doing it.
02
Site rules and the specific risks
The significant risks for this project, not a generic hazard list transplanted from the last one.
03
Pre-construction information carried through
Surveys, asbestos information, ground conditions and services, reaching the people planning the work in a usable state.
04
Revision as the site changes
Sequence changes, new subcontractors, new temporary works. A plan that does not move with them stops describing the site.
What we do
Compiled, cross-checked and kept current
- Compiled from your own materialBuilt from your existing plan, your pre-construction information and the packs in circulation, in your format.
- Drift flagged against live packsWhere the plan describes a sequence or a control that the current RAMS no longer match, that conflict is surfaced with both documents quoted.
- Revision prompts on changeWhen a new package or a new subcontractor arrives, the parts of the plan affected are identified rather than left to memory.
- The duty does not movePlanning, managing and monitoring the construction phase stays with the principal contractor. We prepare and evidence, a person decides.
Being straight about it
Why the record matters when something goes wrong
HSE reported in Construction statistics in Great Britain 2025 that 35 construction workers died in 2024/25, and that the construction fatal injury rate is around 4.8 times the all-industry rate. The HSE fee for intervention rate rose to £188 per hour on 1 April 2026.
When there is an investigation, the question is what you planned, what you checked, when, and what you did about what you found. A construction phase plan that matches the site is evidence. One that describes a mobilisation that ended four months ago is the opposite, because it demonstrates that the arrangements were not being monitored.
This page covers the plan specifically. The wider set of records CDM relies on, including pre-construction information, subcontractor RAMS and the health and safety file, is covered on our CDM 2015 documentation support page.
Common questions
Questions about construction phase plan
What does CDM 2015 require of a principal contractor when reviewing RAMS?
CDM 2015 requires the principal contractor to plan, manage and monitor the construction phase and to coordinate it so that work is carried out without risks to health and safety, which in practice means satisfying yourself that a subcontractor's proposed method and controls are suitable before work starts. The regulations do not prescribe a review format, so the evidence you keep of having checked is what demonstrates you discharged the duty. AI can compile, compare and flag, and it can produce the record of what was checked. It cannot hold the duty. That stays with the dutyholder, and the review decision stays with your competent person. Our CDM documentation article goes through this in more detail.
Does AI replace a competent person under CDM 2015?
No. A competent person is a legal role held by a human being, and no software takes on a CDM 2015 duty. AI can prepare the information that person needs, check documents against each other, highlight what is missing and record what was reviewed, which makes the judgement faster and better evidenced. The judgement itself, and the accountability for it, does not move. Any supplier telling you otherwise is describing something you should not buy.
When does a construction phase plan need to be in place?
Before construction work starts. Under CDM 2015 the principal contractor draws up the plan, or a contractor does where there is only one, and it must be appropriate to the work and kept current as the project changes. The regulations do not prescribe a format or a length, which is often misread as licence to keep it thin. The practical test is whether somebody could read it and understand how this construction phase is being planned, managed and monitored, and whether what it describes matches what is happening on site today.
How do you keep a construction phase plan current?
By tying revision to the things that actually change the work: a new package, a new subcontractor, a change in sequence, new temporary works, or a significant risk that was not there at mobilisation. The failure mode is a plan written once and revisited only when somebody asks for it. We compile the plan from your own material and flag where it has drifted from the RAMS and packs currently in circulation, so the revision conversation is prompted by evidence rather than by an audit. Deciding what the change means, and updating the arrangements, stays with the dutyholder.
Next step
Start with the plan you already have.
Book a short call about your construction phase plan, or send one subcontractor pack for a free check.