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Construction Phase Plan (CDM 2015): What It Must Contain and Who Writes It

By Brian Crocker

Quick answer: The construction phase plan (CPP) is a written document that the principal contractor must prepare before any construction work begins on a notifiable project — or any project with more than one contractor. It sets out health and safety arrangements, site rules, and specific measures for high-risk work. It is not a one-off document: the principal contractor must keep it updated throughout the project.

The construction phase plan is one of the most misunderstood CDM documents. Many contractors produce a generic template, file it away, and never look at it again. Assessors reviewing your accreditation application can spot this immediately — and it is one of the most common causes of a weaker score on your safety management system questions.

This guide explains what the CPP must contain under CDM 2015, who writes it, when it applies, and what accreditation assessors are actually checking when they ask to see your construction phase plan.

Disclaimer: This guidance is based on the Construction (Design and Management) Regulations 2015 and HSE published guidance. TenderReady is not affiliated with the HSE or any accreditation scheme. Always verify requirements directly with the relevant scheme and the HSE.

When Is a Construction Phase Plan Required?

Under the Construction (Design and Management) Regulations 2015 (CDM 2015), a construction phase plan is required on every construction project involving more than one contractor — which means almost all commercial construction work.

The duty is absolute: the principal contractor "must draw up a construction phase plan, or make arrangements for a construction phase plan to be drawn up" before setting up the construction site. There is no threshold below which the duty disappears, other than truly single-contractor domestic work.

For notifiable projects — those lasting more than 30 working days with more than 20 simultaneous workers at any point, or exceeding 500 person-days total — the CPP is a formal document that must exist before the HSE notification is made and site activities begin.

For smaller multi-contractor projects, the CPP can be proportionate to the scale of the work. A two-week refurbishment involving a groundworker and a plumber needs a CPP — but it does not need to be the same length as the CPP for a major new-build.

Who Writes the Construction Phase Plan?

The duty to prepare the CPP sits with the principal contractor — the contractor appointed by the client to plan, manage, monitor, and coordinate the construction phase.

On notifiable projects, the principal designer must assist by providing pre-construction information to the principal contractor. That information forms the foundation of the CPP: hazards and risks identified during design, information about the existing site, and any measures already agreed.

On projects where there is no principal designer — typically smaller projects where the client has not appointed one — the principal contractor must still prepare the CPP, working from whatever pre-construction information the client can provide and their own site assessment.

If you are a smaller subcontractor and not the principal contractor, you are not responsible for writing the overall CPP — but you may be required to contribute information to it (method statements, task-specific risk assessments) and you are required to work in accordance with it.

What a Construction Phase Plan Must Contain

CDM Regulation 12 specifies that the construction phase 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." Where the work falls within the high-risk categories in Schedule 3, the plan must include specific measures for those activities.

In practice, a proportionate CPP for most commercial construction projects covers the following areas:

Project Description and Information

  • Project title, location, and brief description of the work
  • Client identity and their principal points of contact
  • Principal designer identity (if appointed)
  • Principal contractor identity and key contacts
  • Names of other contractors and their activities

Management Arrangements

  • Who is responsible for managing health and safety on site
  • Communication and coordination arrangements between contractors
  • Emergency contacts and procedures
  • How contractors will be briefed on site rules and the CPP itself
  • How the CPP will be kept current and who reviews it

Welfare Provisions

The CDM Regulations require that welfare facilities meeting Schedule 2 requirements are provided from the start of the construction phase. Your CPP should specify:

  • Location and type of welfare facilities (toilets, washing, rest areas)
  • Who is responsible for maintaining them
  • How they will be adapted if the site or workforce changes

Site Rules

Every construction site needs clear rules that all workers, contractors, and visitors must follow. Typical site rules cover:

  • Permit-to-work systems for high-risk activities
  • PPE requirements and where specific equipment must be worn
  • Exclusion zones and restricted areas
  • Vehicle and plant movements on site
  • Smoking, alcohol, and substance policies
  • Accident reporting and near-miss reporting procedures

Risk Management

For the work activities on your site, the CPP should reference or include:

  • The pre-construction information provided by the client or principal designer
  • How significant risks identified in that information will be managed
  • How contractor-specific risk assessments and method statements will be reviewed and coordinated

Schedule 3 High-Risk Activities

If your project involves any of the ten categories of particularly hazardous work listed in CDM Schedule 3 — including work at risk of burial or engulfment, chemical or biological hazard exposure, ionising radiation, proximity to high-voltage power lines, drowning risk, underground works, diving operations, work in compressed air, use of explosives, or assembly of heavy prefabricated components — the CPP must include specific measures for those activities.

These are the elements that most CPP templates overlook, and the ones that assessors focus on for complex projects.

Keeping the CPP Current

A construction phase plan written in week one and never touched again fails the duty. CDM 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."

In practice, this means reviewing and updating the CPP when:

  • New contractors or activities are introduced to the site
  • A significant incident or near-miss occurs
  • The scope of work changes materially
  • The risk profile changes (for example, new underground services are identified, or the programme changes to require more workers on site simultaneously)
  • The construction phase plan's measures are found not to be working as intended

Some principal contractors review the CPP at regular intervals (weekly or fortnightly) as a standard management practice. Others trigger a review only when changes occur. Either approach is acceptable provided the plan stays current.

What Accreditation Assessors Check

When you apply for CHAS, SafeContractor, Constructionline, or another SSIP member scheme accreditation, assessors will ask about your approach to CDM compliance. If you act as principal contractor, they will expect to see evidence that you produce construction phase plans and manage them throughout the project.

Assessors are not checking that your CPP follows a specific template. They are checking that:

You understand what a CPP is and when it applies. A contractor who confuses the CPP with a method statement or a risk assessment has a gap in their CDM knowledge that will be visible.

Your CPP is site-specific. A generic template with placeholder text ("insert site address here") that has never been adapted to a real project is weak evidence. Bring examples from actual projects.

You review and update it. Can you show a revision history? Can you point to updates that were triggered by a change on site?

It connects to your other documents. The CPP should reference or incorporate your method statements, risk assessments, and emergency procedures — not exist in isolation.

Your workers know about it. Under CDM Regulation 13(4), the principal contractor must ensure that "a suitable site induction is provided." The induction should cover the key rules and arrangements in the CPP. Evidence of induction records linked to the CPP strengthens the picture.

For a broader understanding of how CDM duties are distributed across the project team — and where you sit in that structure — see our guide to CDM 2015 duties for SME contractors.

Common Mistakes

Writing the CPP after the construction phase has started. The duty is clear: the CPP must exist before you set up the site. A CPP dated the same day as practical completion is an obvious compliance failure.

Using a generic template without adapting it. HSE's CIS80 template is a useful starting point, not a finished document. Site address, project description, named contacts, and site-specific risk measures must all be filled in.

Forgetting Schedule 3 activities. Contractors working in earthworks, demolition, or working near services frequently encounter Schedule 3 categories and do not include the required specific measures. If the project involves any of the ten categories, the CPP must address them.

No evidence of review. A CPP with no revision history is evidence of a document produced once and filed. Include a version number and review dates on the document itself.

Not sharing it with contractors. Other contractors on site need to work in accordance with the CPP. If they do not have access to it, they cannot comply with it. Record that the CPP has been shared with each contractor.

Using the TenderReady Readiness Scorer

If you are preparing for construction accreditation and want to check whether your CDM documentation — including your construction phase planning arrangements — is ready, the Construction Accreditation Readiness Scorer will identify gaps against the standard SSIP assessment criteria.

Last reviewed: 19 June 2026. Sources: Construction (Design and Management) Regulations 2015, Regulations 12 and 13, and Schedule 3 (legislation.gov.uk/uksi/2015/51); HSE CDM 2015 guidance for principal contractors (hse.gov.uk/construction/cdm/2015/principal-contractors.htm).

Sources

  • CDM 2015 Regulation 12 — construction phase plan and health and safety file
  • CDM 2015 Regulation 13 — principal contractor duties during construction phase
  • CDM 2015 Schedule 3 — work involving particular risks
  • CDM 2015 Regulation 6 — notifiable project thresholds
  • HSE CDM 2015: principal contractors guidance