A principal contractor must prepare a construction phase plan before any construction work begins. This is not best practice — it is a legal requirement under the Construction (Design and Management) Regulations 2015, and it applies to every UK construction project, no matter how small.
Yet on most projects the construction phase plan is treated as paperwork: a folder pulled out for the auditor, then forgotten. That is the wrong way to look at it. A construction phase plan that genuinely covers the site-specific risks is one of the single most useful documents you can produce — and one of the easiest to get wrong.
This guide explains what the regulations actually require, what HSE expects to see in the plan, when you can scale it down, and how to produce one efficiently. You can also download our free construction phase plan template to use as a starting point.
What a construction phase plan is
The construction phase plan is the document that sets out how health and safety will be managed during the construction phase of a project. It is prepared by the principal contractor (or on single-contractor projects, by the contractor) and is required by Regulation 12 of the Construction (Design and Management) Regulations 2015 (SI 2015/51).
A construction phase plan is site-specific. A generic template populated with boilerplate is not a construction phase plan — HSE has been explicit about this in guidance and enforcement decisions. The plan must address the actual hazards present on the actual job, with the actual control measures the actual workforce will use.
It is also a living document. The construction phase plan written before work starts is the baseline. As the project progresses — new contractors arrive, the design changes, new hazards emerge — the plan must be updated to reflect what is actually happening on site.
When is a construction phase plan legally required?
A construction phase plan is required on every CDM project, which is to say every project involving construction work in Great Britain. There is no minimum project size below which the requirement disappears. Regulation 12(1) of CDM 2015 states:
"During the pre-construction phase, and before setting up a construction site, the principal contractor must draw up a construction phase plan, or make arrangements for a construction phase plan to be drawn up."
The same requirement applies to single-contractor projects under Regulation 15(5), where the contractor (rather than the principal contractor) is responsible for the plan.
What changes by project size is the level of detail expected — not whether the plan is required at all. HSE's guidance L153 ("Managing health and safety in construction") makes clear that a domestic kitchen extension does not need the same level of documentation as a multi-storey office build. But both need a plan.
Notifiable projects
A construction project is "notifiable" to HSE if it will last longer than 30 working days and have more than 20 workers working simultaneously at any point, or if it will exceed 500 person-days of construction work (Regulation 6). The notification requirement is separate from the construction phase plan requirement — both can apply, neither cancels the other.
For notifiable projects, the client must give notice to HSE via form F10 before construction starts. The construction phase plan is still required regardless of notifiability.
What the construction phase plan must contain
CDM 2015 does not prescribe a fixed structure for the plan. Regulation 12(2) requires the principal contractor to address the matters specified in Schedule 3 — a list of high-risk work categories that may need particular management attention — and HSE guidance L153 ("Managing health and safety in construction") sets out the practical content of a construction phase plan in detail. The plan should cover, in proportion to the project:
1. A description of the project
What is being built, where, by whom, and over what timeframe. This sets context for everything that follows — the same hazard on a city-centre refit needs different controls than on a rural new-build.
Include the project name and address, the client, the principal designer, the principal contractor, the contractors known at the time of writing, the planned start and end dates, and a short description of the works. If the project is notifiable, attach a copy of the F10.
2. The management of the work
How health and safety will be managed across the construction phase. This is the section that distinguishes a real plan from a template. Cover:
- The site rules — who has authority to stop work, who signs off changes, how briefings are run, how incidents are reported and investigated.
- Communication and coordination between contractors, particularly where work overlaps in time and space.
- How design changes during construction will be managed.
- Welfare arrangements (toilets, washing, drinking water, rest, changing facilities) per Schedule 2 of CDM 2015.
- Site induction process — what every worker is told before starting work, and how attendance is recorded.
3. The arrangements for controlling significant site risks
The pre-construction information from the client and principal designer should have flagged the significant hazards the project will face. The construction phase plan turns those hazards into specific controls.
This is where the plan goes site-specific. For each significant hazard:
- The hazard itself (work at height above 4 metres, demolition adjacent to public footpath, hot works in occupied building, etc.).
- The control measures (collective protection first, PPE last — per the hierarchy in Schedule 1 to the Management of Health and Safety at Work Regulations 1999).
- Who is responsible for maintaining the control.
- The supporting documents — RAMS, permits-to-work, lift plans, exclusion zone drawings — that operationalise the control.
Schedule 3 of CDM 2015 lists ten categories of work involving particular risks — including work at height where the risk is particularly aggravated, work near high voltage power lines, work exposing workers to the risk of drowning, work on wells and underground earthworks, work involving explosives, and work assembling or dismantling heavy prefabricated components. Regulation 12(2) requires the plan to include specific measures for any Schedule 3 category that applies to the project. Where other hazards arise — work at lower heights, hot works, electrical work, asbestos (covered by the Control of Asbestos Regulations 2012), confined spaces (covered by the Confined Spaces Regulations 1997) — the plan must still address them under the broader "health and safety arrangements" requirement.
4. The health and safety file
For projects with more than one contractor, the principal designer (or in their absence, the principal contractor) must prepare the health and safety file at the end of the project. The construction phase plan should explain what information will be collected during construction to feed into that file — residual hazards, as-built drawings, manuals for installed plant.
What the construction phase plan must NOT be
HSE's enforcement guidance is unambiguous: a generic plan dropped into a project folder is worse than no plan, because it creates a false impression of compliance. Specifically:
- A construction phase plan is not a paperwork exercise. It must be communicated to the workforce — through induction, toolbox talks, and ongoing briefings. If the people doing the work do not know what the plan says, the plan does not exist for practical purposes.
- A construction phase plan is not a risk assessment. The plan summarises the management approach and points to the underlying RAMS, permits, and method statements. The detail lives in those documents; the plan ties them together.
- A construction phase plan is not the client's pre-construction information. The PCI is the input that the principal designer and client provide to the principal contractor. The construction phase plan is what the principal contractor builds from that input. The two are separate documents with separate authors.
How to scale the plan to the project
The same legal requirement applies to a £5,000 bathroom refit and a £50M commercial fit-out, but the documents should not look the same. HSE guidance and enforcement practice both support scaling:
- Small / low-risk projects (e.g. domestic refurbishment, single trade, no work at height above 2 m, no notifiable hazards): the plan can be 2-4 pages covering the four sections above briefly. The site rules and induction process can be a single page. Risk arrangements can reference the standard RAMS for the trade.
- Medium projects (multi-contractor, mixed trades, some Schedule 3 risks present): expect 10-20 pages, with appendices for site rules, induction script, and a hazard-by-hazard control summary referencing supporting RAMS.
- Large / notifiable projects (more than 30 days and more than 20 workers, or more than 500 person-days; or any work involving Schedule 3 hazards): full plan with substantive sections on each of the four areas, embedded site logistics drawings, permit-to-work register, and a structured schedule of how the plan will be reviewed and updated.
The test is not page count — it is whether the document accurately describes how the principal contractor will plan, manage, monitor and coordinate the work, and whether that information is available to anyone on site who needs it.
When the plan needs updating
The construction phase plan is a live document. Trigger events that require an update include:
- A new contractor joining the project, particularly one bringing trade-specific risks not previously covered.
- A design change introducing new hazards or removing previously identified ones.
- An incident or near-miss that reveals a gap in the existing controls.
- A change in site layout, access route, or boundary that affects pedestrian or vehicle separation.
- A regulatory change affecting the project (rare but possible — e.g. higher-risk building enforcement under the Building Safety Act for in-scope projects).
Each update should be dated, the change summarised, and the updated section communicated to the workforce affected. A change log at the front of the plan is the simplest way to track this.
Who needs access to the plan
Anyone working on site needs access to the parts of the plan that affect their work. In practice this means:
- The plan as a whole is held by the principal contractor and made available to inspecting authorities (HSE, local authority).
- The site rules and induction content are delivered to every worker before they start.
- The arrangements for controlling specific hazards are communicated to the contractors and workers responsible for that work, normally via the contractor's own RAMS and permit-to-work process.
Storage matters too. A construction phase plan on a laptop in the project manager's car is not accessible. A digital version available to every site supervisor, paired with hard copies in the site office, is.
Common construction phase plan failures
Reviewing HSE enforcement notices and incident reports surfaces the same recurring issues:
- Boilerplate text not edited for the site. Generic "work at height to be controlled by appropriate measures" without any site-specific detail about which heights, which trades, and which controls.
- No version control. Plan written at tender, never updated, no revision history. By month three of the project, the document bears no relation to what is happening on site.
- No evidence of communication to the workforce. Plan exists but no induction records, no toolbox talks referencing it, no signed copies of site rules. From an HSE perspective, this looks like a plan that exists only on paper.
- Risk arrangements with no owner. "Asbestos to be managed in accordance with regulations" — by whom? With what authority? Following what procedure? Each control needs a named responsible person.
- PCI not addressed. The pre-construction information from the client and principal designer raised specific hazards. The construction phase plan does not respond to them. This is one of the most common gaps and one of the easiest to spot.
Using a construction phase plan template
A template is a useful starting point — particularly for principal contractors who do not produce plans frequently. But a template must be edited, not just filled in.
Our free construction phase plan template provides the section structure aligned with CDM 2015 Regulation 12 and HSE guidance L153, with prompts in each section to make sure the content stays site-specific. It is intended as a working document — open it, customise it for your project, and update it as the work progresses.
For a comprehensive overview of all five CDM duty holder roles and how the construction phase plan fits into the wider compliance picture, see our CDM compliance guide. For the specific duties of a principal contractor, see CDM principal contractor duties.
How software supports construction phase plan management
A construction phase plan is more useful when the information feeding it is current. The risks on site change as subcontractors come and go; the controls in the plan should follow.
Subcontractor compliance software automates the parts of that information flow that are otherwise manual: which contractors are currently approved to work on site, whether their insurance and CSCS cards are still valid, which RAMS are signed off for which packages of work. When a subcontractor's documentation expires, the plan can be flagged for review — instead of waiting for the next audit to discover the gap.
SubComply is being built specifically for this — a single dashboard for subcontractor compliance status that feeds into the construction phase plan workflow. Join the waitlist for early access.