CDM 2015,
explained.
Plain English.
The Construction (Design and Management) Regulations 2015 are the spine of UK construction safety law. This page is a working reference — what the regulations require, who has to do it, what evidence is expected and what happens if you get it wrong. Written for a UK SME, not a textbook.
What CDM 2015 is, and what it replaced.
The Construction (Design and Management) Regulations 2015 came into force on 6 April 2015 and replaced CDM 2007. They are made under the Health and Safety at Work etc Act 1974 and apply to all construction projects in Great Britain — domestic, commercial, civil engineering, fit-out, demolition, refurbishment. There is no minimum project size. A loft conversion is in scope. A motorway widening is in scope.
The headline change from CDM 2007 was the removal of the CDM Co-ordinator role and its replacement with the Principal Designer, who carries pre-construction phase duties. The 2015 regulations also pulled domestic clients into scope (their duties pass automatically to the contractor or principal contractor) and lowered the threshold for HSE notification.
The regulations do not exist for paperwork's sake. They exist because UK construction has historically killed and maimed people at a far higher rate than other industries, and the evidence that a project was managed safely has to be provable, not asserted. CDM 2015 is the framework that turns "we ran a tight site" into a record someone can read.
Who has duties under CDM 2015.
CDM 2015 names five duty holders, plus workers. Every project has at least three — Client, Designer (one or more), and Contractor (one or more). Most projects also have a Principal Designer and a Principal Contractor.
- Client — the organisation or person commissioning the work. Has overall responsibility for managing the project, appointing the right people, and providing pre-construction information.
- Principal Designer — appointed by the client where there is more than one contractor. Coordinates the pre-construction phase, manages design risk, prepares the H&S file.
- Designer — anyone preparing or modifying a design. Includes architects, engineers, surveyors, and (sometimes) contractors who design temporary works.
- Principal Contractor — appointed by the client where there is more than one contractor. Coordinates the construction phase, prepares the Construction Phase Plan, manages site rules.
- Contractor — any individual or business that carries out construction work. The trade subbie installing the windows. The plant-hire firm with an operator on site.
- Workers — anyone working on the construction site. Workers must follow the rules, report risks, and take care of themselves and others.
On smaller projects, the same person or firm can hold several roles. A small builder doing a domestic conversion is often the Designer, the Contractor and (by automatic transfer from the domestic client) the Principal Contractor.
Pre-Construction Information (PCI).
The PCI is the file the client gathers and provides to designers and contractors before construction starts. It describes the site, the project, hazards already known about, and the resources allocated to managing them. The PCI is the input that lets a competent contractor price and plan safely.
For a refurbishment, the PCI typically includes asbestos surveys, structural condition reports, services drawings, previous H&S files, and any restrictions on access or hours. For new build, it covers ground conditions, services, neighbouring buildings, traffic management, welfare arrangements, and the project timetable. The client cannot delegate the duty to provide it, but can ask the Principal Designer to assemble it.
Construction Phase Plan (CPP).
The CPP is the Principal Contractor's plan for managing the construction phase. It must be in writing, project- specific, proportionate to the project, and in place before construction begins. A standard template can be a starting point but a generic CPP is not compliant — the document must engage with the actual hazards of the actual site.
At minimum a CPP covers site rules, welfare, emergency procedures, traffic management, key risks and the control measures, the programme, and how the principal contractor will manage subcontractors. It is a living document — updated as the project evolves, the substructure becomes superstructure, and new trades come on site.
The Health and Safety File.
The H&S file is the document handed to the client at the end of the project, for use during occupation, maintenance, future refurbishment and eventual demolition. It records the residual risks and information that anyone working on the building in future would need to know about — not the risks that have been designed out, but the ones that remain.
It is the Principal Designer's responsibility to prepare and update the file through design and construction. At handover the Principal Contractor passes any final construction-phase information across, and the file goes to the client. Keep it. The H&S file you start ten years from now starts with the file you got at handover.
F10 — when you must notify HSE.
The client must notify HSE on form F10 if the project is expected to last more than 30 working days with more than 20 workers working simultaneously at any point, or more than 500 person-days in total (Reg 6). The notification must be made before construction begins, and a copy of the most recently updated F10 must be displayed on site.
F10 thresholds catch most commercial and civil projects and miss most domestic refurbishments. If you are close to a threshold and unsure, notify — there is no penalty for over-notifying.
Welfare arrangements (Schedule 2).
Schedule 2 of CDM 2015 sets out the welfare facilities that must be provided on every site, regardless of size. The list is short and absolute: toilets, washing facilities, drinking water, changing rooms (where workers wear special clothing), facilities for rest, and somewhere to eat and prepare hot drinks.
Schedule 2 is not negotiable. "It's only a small site" is not a defence. "The client wouldn't pay for it" is not a defence — the client and the principal contractor both have a duty to ensure welfare is provided. A site without welfare is a site that should be stopped.
Common compliance failures.
The HSE's enforcement notices on construction sites tell a consistent story year on year. The failures cluster into a small number of patterns:
- Late or missing CPP — work began before the plan was written, or the plan was generic and did not reflect the site.
- RAMS not signed — risk assessments and method statements existed on paper but operatives had not seen, signed or been briefed on them.
- Welfare absent — no toilets, no clean water, no rest area on a site that has been running for weeks.
- Plant out of date — telehandlers and excavators with expired LOLER or PUWER certs still in use.
- F10 not displayed — notification made but the printed form not on the cabin wall, or the site has changed and the F10 has not been updated.
- H&S file inadequate — handed over with key information missing, leaving future occupants exposed.
What the penalties are.
Breaches of CDM 2015 are prosecuted under the Health and Safety at Work etc Act 1974. Penalties can be substantial — magistrates' courts can issue unlimited fines, and serious cases go to the Crown Court where custodial sentences are possible. Sentencing follows the Definitive Guideline for Health and Safety Offences, Corporate Manslaughter and Food Safety and Hygiene Offences, which considers culpability, harm and the size of the organisation.
The reputational cost is often higher than the financial one. HSE prosecutions are public. Insurers raise premiums. Tier-1 contractors drop subcontractors with recent enforcement notices. A single avoidable incident can eliminate a year of margin and threaten the firm's ability to bid for future work.
The CDM 2015 file
builds itself as the
job runs.
Every duty above maps to a record on the platform. PCI attaches at kick-off. CPP starts from a template and evolves through the project. H&S file compiles from real activity. At handover or audit, one click and the file is a single PDF.
PCI at kick-off
Asbestos surveys, structural reports, services drawings, hazard registers — pinned to the project record from day one. Designers and contractors see the same file, the same version.
Reg4(4)CPP that evolves
Start from a sector template, configure for your site, update as trades land. Version control built in. CPP is searchable, attached to the project, and downloadable as a single PDF.
Reg12RAMS at the gate
Every operative signs today's RAMS at the QR clock-in. Photograph, GPS, timestamp. The audit trail covers everyone, every shift, unfakeable.
Reg13F10 reminders
Project setup checks the thresholds. If you are close to F10 on duration or workers, the platform flags it, generates the form, and reminds you to display the latest copy.
Reg6Welfare confirmations
Photo evidence at site setup. Reviewed weekly. Schedule 2 line items tracked per site, alerted when a re-check is due. The defence is in the data.
Sched2One-click H&S file
At handover or audit, one PDF: PCI, CPP, RAMS history, RIDDOR records, training matrix, welfare confirmations, plant compliance. The auditor reads it on first pass.
Cuts2 wks → 1 hr