Every UK construction project — from a bathroom refit to a multi-storey commercial build — requires a construction phase plan (CPP) under the Construction (Design and Management) Regulations 2015. This guide explains the legal basis, who must produce it, what it must contain, and how Ramsdocs helps you get there faster.
What Is a Construction Phase Plan? (Legal Definition Under CDM 2015)
A construction phase plan is the documented record of health and safety arrangements for the construction phase of a project. CDM 2015 regulation 12(1) requires that 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. Regulation 12(2) specifies that the plan must set out the health and safety arrangements and site rules, taking account where necessary of the industrial activities taking place on the construction site.
The plan is not a one-off form. CDM 2015 regulation 12(4) requires that throughout the project the principal contractor must ensure that the construction phase plan is appropriately reviewed, updated and revised from time to time so that it continues to be sufficient to ensure that construction work is carried out, so far as is reasonably practicable, without risks to health or safety.
The CPP is a live document. It starts before the first spade goes in and must reflect actual site conditions throughout.
Who Must Prepare It — The Two Duty-Holder Regimes Explained
The identity of the plan's author depends on the structure of the project. These two regimes operate quite differently in practice.
| Scenario | Project type | Who prepares the CPP? | Key CDM basis |
|---|---|---|---|
| Sole/domestic contractor | Single-trade domestic job (one contractor only) | The contractor in control of the construction phase | HSE CIS80 |
| Principal contractor | Any project involving more than one contractor | The appointed principal contractor | CDM 2015 reg 12 & reg 13 |
Domestic client projects: Where the builder is working for a domestic client and is either the only contractor or the principal contractor, that builder is responsible for preparing the plan, organising the work, and working together with others to ensure health and safety (HSE CIS80). When working for a domestic client, the principal contractor will normally take on the client duties as well as their own as principal contractor (HSE).
Multi-contractor projects: A principal contractor is appointed by the client to control the construction phase of any project involving more than one contractor. The principal contractor must plan, manage, monitor and coordinate the entire construction phase, taking account of health and safety risks to everyone affected by the work including members of the public (HSE). The principal contractor must have the skills, knowledge, experience and, where relevant, organisational capability to carry out this work (HSE).
Important: The principal designer's role in providing pre-construction information to assist the principal contractor is a separate and distinct duty. Do not conflate the principal designer's pre-construction phase input with the principal contractor's obligation to draw up and own the CPP.
Anyone responsible for appointing designers or contractors must ensure that those appointed have the skills, knowledge and experience to carry out the work in a way that secures health and safety, and must establish this before making the appointment (HSE L153).
What a Construction Phase Plan Must Contain: Section-by-Section Breakdown
CDM 2015 does not prescribe a fixed template, but regulation 12(2) and the HSE CIS80 guidance together define the territory the plan must cover. HSE's CIS80 template groups requirements under three headings: Plan, Organise, and Working Together.
At minimum, every CPP — however simple — must address:
- Project description and key dates — start, finish, key build stages, service connections/disconnections
- Pre-construction site information — what the client has disclosed about the property (services, isolation points, access restrictions, asbestos)
- Significant hazards and control measures — falls from height, collapse of excavations or structures, exposure to building dusts, asbestos, electricity, risks to members of the public
- Welfare arrangements — toilet, washing and rest facilities
- Management and coordination — who is the named responsible person, how supervision is provided, how information will be communicated to others on site
Pre-work planning should gather health and safety information about the project and the proposed site before work begins, paying particular attention to asbestos or other contaminants, overhead power lines and underground services, unusual ground conditions, public rights of way, nearby schools, footpaths, roads or railways, and other activities on site (HSE HSG150). HSG150 predates CDM 2015 — its regulatory references are superseded — but its site-hazard planning checklist remains sound practice, and these categories map directly to the information-gathering fields in any sound CPP.
CDM 2015 also requires designers, principal designers, principal contractors and contractors to take account of the general principles of prevention — avoid risks where possible, evaluate those that cannot be avoided, and put in place proportionate measures that control them at source — in carrying out their duties (HSE L153). The CPP is the place where this hierarchy is documented.
When Must the Plan Be Ready — and How Often Must It Be Updated?
The CPP must exist before the construction phase begins. CDM 2015 regulation 12(1) is explicit: the plan must be drawn up during the pre-construction phase and before setting up a construction site.
Once work starts, the plan must be kept live. The duty under regulation 12(4) to review, update and revise the plan is ongoing — not periodic. In practice, the CPP should be revisited whenever:
- A new contractor or trade joins the site
- A significant change occurs to the scope, sequence or method of work
- An incident or near miss occurs that reveals an uncontrolled risk
- Site conditions change materially (e.g. discovery of contamination)
Notification Thresholds: When a Simple Plan Is Not Enough
A construction phase plan is required for every construction project without exception under CDM 2015 (HSE CIS80). The threshold question is about format and complexity, not whether a plan is needed at all.
If a job will last longer than 500 person days or 30 working days with more than 20 people working simultaneously, it must be notified to HSE and is likely to be too complex for the simple CIS80 plan format (HSE CIS80).
Below these thresholds, a simple plan before the work starts is usually enough for small-scale domestic jobs such as installing a kitchen or bathroom, structural alterations (e.g. chimney breast removal), roofing work including dormer windows, or an extension or loft conversion (HSE CIS80).
The Unique Asset: Worked Examples + Annotated CPP Compliance Checklist
Scenario A — Single-Trade Domestic Builder (Loft Conversion)
Project: Sole trader carrying out a dormer loft conversion for a domestic client. No other contractors on site. Duration: 6 weeks. Below notification threshold.
Under CIS80, this builder is responsible for the CPP. The plan must cover five areas before work starts. The table below maps each CIS80 field to its CDM obligation and shows whether Ramsdocs auto-generates or prompts manual input.
| CPP Section (CIS80 field) | CDM 2015 obligation it satisfies | Responsible duty holder | Ramsdocs output |
|---|---|---|---|
| Project description, key dates, build stages | Reg 12(1) — plan drawn up before construction begins | Sole contractor | Auto-populated from project intake form |
| Client-provided site information (services, asbestos, access) | Reg 12(2) — health and safety arrangements; HSG150 pre-work planning | Sole contractor (from client) | Prompted — contractor confirms or adds detail |
| Significant hazards and control measures (falls, collapse, dust, asbestos, electricity, public safety) | Reg 12(2) — health and safety arrangements and site rules | Sole contractor | Auto-populated with task-relevant hazard library; contractor reviews and adapts |
| Welfare arrangements (toilet, washing, rest) | CDM 2015 Schedule 2 — welfare facility requirements (contractor duty) | Sole contractor | Auto-populated from site type selection |
| Management, supervision and communication (named responsible person, how updates reach others) | Reg 12(2) — site rules; CIS80 'Working Together' section | Sole contractor | Auto-populated from named supervisor field |
Output: A single-page, PC review-ready plan. Contractor must review and adapt to actual site conditions before work begins.
Scenario B — Principal Contractor on a Notifiable Project
Project: Principal contractor managing a two-storey commercial extension. Eight subcontractors. Duration: 14 weeks, peak of 28 workers on site simultaneously. Notifiable (exceeds 30 working days with more than 20 simultaneous workers).
The plan must be substantially more detailed. The table below maps CDM 2015 regulation 12 and regulation 13 duties to the corresponding CPP sections, and distinguishes what must exist before work begins from what must be kept live throughout.
| CPP Section | CDM 2015 duty | Responsible party | Before work begins or ongoing? | Ramsdocs output |
|---|---|---|---|---|
| Project description, client details, principal designer contact | Reg 12(1) | Principal contractor | Before | Auto-populated |
| Pre-construction information (from client and principal designer) | Reg 12(3) — principal designer provides all relevant information | Principal designer → PC | Before | Prompted — PC uploads or records PD-supplied info |
| Health and safety arrangements and site rules | Reg 12(2) | Principal contractor | Before | Auto-populated with site-type rule library |
| Significant site hazards and control measures (including HSG150 site survey items: asbestos, services, ground conditions, adjacent land uses) | Reg 12(2); HSG150 pre-work planning | Principal contractor | Before | Auto-populated with project-specific hazard prompts |
| Coordination of contractors — cooperation, induction, information sharing | Reg 13(3) — organise cooperation, coordinate H&S requirements | Principal contractor | Before + Ongoing | Prompted — contractor matrix auto-generated |
| Site induction arrangements | Reg 13(4)(a) | Principal contractor | Before + Ongoing | Auto-populated template |
| Preventing unauthorised access | Reg 13(4)(b) | Principal contractor | Before + Ongoing | Auto-populated from site security selections |
| Welfare facilities | Reg 13(4)(c) | Principal contractor | Before + Ongoing | Auto-populated from headcount and site type |
| Worker consultation arrangements | Reg 14 — PC duty to consult and engage with workers; L153 | Principal contractor | Ongoing | Prompted |
| Plan review log | Reg 12(4) — reviewed, updated and revised throughout | Principal contractor | Ongoing | Auto-generated revision history |
The principal contractor must plan, manage and monitor the construction phase and coordinate matters relating to health and safety during the construction phase (CDM 2015 reg 13(1)). The principal contractor must also organise cooperation between contractors, coordinate implementation of applicable legal requirements, and ensure workers follow the construction phase plan (CDM 2015 reg 13(3)).
Common CPP Failures and How to Close the Gaps
The five most frequently incomplete CPP sections — drawn from the pre-work planning principles in HSG150 and the CIS80 template fields — and the control that closes each gap:
| Failure | What the gap looks like | Control that closes it |
|---|---|---|
| No asbestos information recorded | Plan states "no asbestos" without evidence of a survey or client confirmation | Record client-provided asbestos information; confirm a refurbishment/demolition survey has been carried out before intrusive work begins |
| Hazard list is generic, not site-specific | Template hazards copied in without confirming which are present | Complete the CIS80 "Hazard is present" column for every listed hazard; delete those genuinely absent |
| Welfare arrangements left blank | No entry for toilet, washing or rest facilities | Name the specific facilities on or adjacent to the site before work starts |
| No named responsible person | Plan does not identify who ensures the job runs safely | Insert a named individual — not a role title — for on-site health and safety responsibility |
| Plan never updated after work starts | Original plan filed and not revisited when scope or subcontractors change | Establish a review trigger (new trade on site, scope change, incident) and record each review in a revision log |
How Ramsdocs Produces a Compliant Construction Phase Plan in Minutes
Ramsdocs is built around the CDM 2015 duty-holder structure. When you start a project, the platform determines which regime applies — sole domestic contractor or multi-contractor principal contractor — and routes you to the appropriate CPP format.
What Ramsdocs auto-populates:
- Project and client fields from your intake form
- Hazard libraries matched to your project type and trades on site
- Site rules, welfare provisions, and induction arrangements from your site profile
- A contractor coordination matrix for multi-contractor projects
- A live revision log to satisfy the regulation 12(4) ongoing review duty
What requires your input:
- Client-disclosed site information (asbestos, services, access restrictions)
- Confirmation that each hazard in the library is present or absent on your specific site
- Named responsible persons and supervisors
- Pre-construction information supplied by the principal designer (notifiable projects)
The result is a CPP that is PC review-ready and designed to reduce RAMS rework — not a one-click guarantee of compliance. Every plan Ramsdocs generates must be reviewed and adapted to your specific site, task and contractor arrangements by a competent person before the construction phase begins.
FAQ
Does every construction project need a construction phase plan? Yes. A construction phase plan is required for every construction project without exception under CDM 2015 (HSE CIS80). The threshold question affects the plan's complexity, not whether one is needed.
Who is responsible for preparing the construction phase plan? On a domestic project with a single contractor, that contractor is responsible. On any project involving more than one contractor, the appointed principal contractor must draw up the plan before the construction phase begins (CDM 2015 reg 12(1)).
What must a construction phase plan contain? At minimum: project description and key dates, client-provided site information, significant hazards and control measures, welfare arrangements, and management and supervision arrangements. Notifiable projects require considerably more detail including contractor coordination, induction arrangements and a live revision log.
When must the plan be in place? Before the construction phase begins — before setting up the construction site. CDM 2015 regulation 12(1) is explicit on this point.
What are the notification thresholds? A project must be notified to HSE if it will last longer than 500 person days, or 30 working days with more than 20 people working simultaneously (HSE CIS80). These are the exact thresholds stated in CIS80 — do not substitute alternative figures.
Does a simple domestic job really need a formal plan? Yes, but a simple plan before the work starts is usually enough for small-scale domestic jobs such as installing a kitchen or bathroom, structural alterations, roofing work, or an extension or loft conversion (HSE CIS80). The CIS80 one-page template satisfies the duty for these jobs.
How often must the plan be updated? The plan must be reviewed, updated and revised throughout the project so that it remains sufficient (CDM 2015 reg 12(4)). In practice, review it whenever scope, personnel or site conditions change materially.
Disclaimer: This page is intended as general guidance only. Every construction phase plan must be reviewed and adapted to the specific site, task, and contractor arrangements by a competent person before the construction phase begins. Nothing on this page constitutes legal advice or guarantees that any document produced will be accepted by a principal contractor, client, or enforcing authority. Ramsdocs outputs are designed to reduce RAMS rework — not to remove the need for professional review.
Frequently Asked Questions
What information must the principal designer pass to the principal contractor before the construction phase plan is drawn up? Under CDM 2015 regulation 12(3), the principal designer must assist the principal contractor in preparing the construction phase plan by providing all information the principal designer holds that is relevant to it — specifically, pre-construction information obtained from the client and any information obtained from designers under regulation 9(3)(b). In practice this means the principal contractor should not begin drafting the CPP in an information vacuum; the handover of the principal designer's collated pre-construction information is a formal step that feeds directly into the CPP's hazard and control sections. Early appointment of the principal contractor — before the construction phase begins — gives both parties time to work through this transfer before site is set up.
Does the principal designer's duty to assist with the CPP mean they share responsibility for its contents? No. Regulation 12(3) places an obligation on the principal designer to provide relevant information to the principal contractor; ownership of the CPP itself remains with the principal contractor under regulation 12(1) and 12(4). The principal designer's contribution is an input, not a co-authorship — the principal contractor must satisfy themselves that the plan adequately reflects all information received and any additional hazards identified during their own pre-construction planning.
Who is responsible for the health and safety file if the principal designer's appointment ends before the project is finished? CDM 2015 regulation 12(5) places the initial duty to prepare the health and safety file on the principal designer during the pre-construction phase, but in practice the file must be kept current as construction proceeds. Where the principal designer's appointment concludes before handover, the principal contractor should pick up responsibility for continuing to gather and collate relevant information so the file is complete when it is passed to the client — good practice is to agree the format and handover arrangements between the two duty holders at the outset rather than leaving this to the end of the project.
Sources Used
This guide is checked against official source material. Verify current legal duties against the live legislation and HSE guidance before relying on the content for a live project.
- Management of Health and Safety at Work Regulations 1999, regulation 3 (legislation.gov.uk)
- Construction (Design and Management) Regulations 2015 (legislation.gov.uk)
- Managing risks and risk assessment at work (HSE)
- Planning for construction work (HSE)
Put This Guide To Work
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