CDM Regulations 2015 Explained: Duties, Checklists & Compliance for UK Construction Sites
The Construction (Design and Management) Regulations 2015 — known as CDM Regulations 2015 — are the backbone of UK construction safety law. Yet HSE inspectors still cite poor planning and weak compliance documentation as leading causes of enforcement action across British sites every year.
If you’re a client, principal designer, principal contractor or site manager, this guide explains exactly what CDM 2015 requires of you, who counts as a duty holder, which documents you must produce, and how to stay audit-ready without drowning in paperwork. We’ll cover real-world compliance steps, a practical CDM checklist, and the digital tools that turn safety planning from a chore into a routine.
What Is CDM in Construction?
The Construction (Design and Management) Regulations 2015 — typically shortened to CDM 2015 — set out the legal framework for managing health, safety and welfare across every construction project in Great Britain. They came into force on 6 April 2015, replacing the older CDM 2007 regulations.
CDM regulations 2015 require everyone involved in a project — from the client commissioning the work to the labourer on site — to plan, manage and coordinate health and safety from concept through to completion.
So when someone asks what is CDM in construction, the short answer is this: a legal duty to design risk out of buildings before tools ever hit the ground.
When Do CDM 2015 Regulations Apply?
CDM 2015 applies to all construction work in Great Britain, including:
- New build, refurbishment and extensions
- Demolition and dismantling
- Repair, maintenance and decommissioning
- Civil engineering and groundworks
- Both commercial and domestic projects
There is no minimum project size. A single-day repair on a domestic property still falls under CDM. The scale of duties grows with the complexity of the work — but the principles always apply.
Notifiable vs Non-Notifiable Projects (F10)
A project becomes notifiable to the Health and Safety Executive (HSE) if it lasts longer than 30 working days with more than 20 workers on site at any one time, or exceeds 500 person-days of work. In those cases, the client must submit Form F10 before construction begins.
Non-notifiable projects still require the same duty-holder structure and documentation — the only difference is the F10 submission. Don’t mistake “no F10” for “no compliance”.
Who Are the CDM 2015 Duty Holders?
CDM regulations 2015 define five duty holders, each with specific legal responsibilities:
- Clients — anyone commissioning construction work in connection with a business
- Principal Designers — appointed where more than one contractor is involved
- Designers — anyone preparing or modifying designs
- Principal Contractors — appointed where more than one contractor is involved
- Contractors — anyone carrying out construction work
Workers also have duties under CDM 2015, but aren’t classed as duty holders. When only one contractor is on site, principal-designer and principal-contractor duties default to the designer and contractor respectively.
Client Duties Under CDM 2015
The client carries the most fundamental responsibility. Whether commercial or domestic, clients must:
- Make suitable arrangements for managing the project
- Allocate sufficient time and resources for safe delivery
- Appoint a principal designer and principal contractor in writing
- Provide pre-construction information to all duty holders
- Ensure a construction phase plan and health and safety file are produced
Domestic clients have many of these duties transferred to the contractor or principal contractor under Regulation 7 — but they’re not absolved from the regulations entirely.
Principal Designer Duties
Principal designer duties cover the pre-construction phase — the design and planning stage. They include:
- Planning, managing, monitoring and coordinating health and safety in the pre-construction phase
- Identifying, eliminating or controlling foreseeable risks
- Coordinating designers’ work to ensure safe delivery
- Preparing and providing the health and safety file
- Ensuring all designers comply with their duties
The principal designer must be appointed before any design work begins. Failure to appoint one in writing is one of the most common breaches HSE inspectors find on smaller projects.
Principal Contractor Duties
Principal contractor duties take over at the construction phase. They include:
- Planning, managing, monitoring and coordinating health and safety on site
- Producing and maintaining the construction phase plan
- Liaising with the client and principal designer throughout the project
- Ensuring suitable site induction, welfare facilities and worker engagement
- Preventing unauthorised access to the site
The principal contractor translates the principal designer’s planning into day-to-day site reality. Strong communication between the two roles is the difference between paper compliance and genuine safety.
Designers and Contractors
Designers must eliminate foreseeable risks in their designs where possible, reduce risks where elimination isn’t practicable, and provide information to other duty holders about residual risks. Contractors must carry out work in line with the construction phase plan, ensure their workers are competent, and report incidents through agreed channels.
CDM 2015 Compliance Documents You Must Produce
Three documents form the spine of CDM compliance.
Pre-Construction Information (PCI)
Provided by the client (with designer input), the PCI describes everything the team needs to know before construction starts: site conditions, existing structures, hazards, design assumptions and project programme. It feeds directly into the construction phase plan.
Construction Phase Plan (CPP)
The principal contractor produces and maintains the CPP. It documents the arrangements for managing the construction phase — organisation, risk controls, site rules, emergency procedures, and how the work will progress. It must exist before construction starts — not be written retrospectively.
Health and Safety File
Compiled by the principal designer and handed to the client at completion, the H&S file contains the information future occupiers and contractors need to maintain or refurbish the building safely. It’s a living document, updated whenever significant changes happen.
A Practical CDM Compliance Checklist
Use this CDM checklist at the start of every project to confirm you’re on the right footing:
- Confirm the project’s scope, duration and number of contractors involved
- Determine whether the project is notifiable (over 30 days / 20 workers, or 500 person-days)
- Submit Form F10 to HSE if notifiable
- Appoint a principal designer in writing before design work begins
- Appoint a principal contractor in writing before construction begins
- Issue Pre-Construction Information to all designers and contractors
- Confirm a Construction Phase Plan is in place before any work starts
- Verify all duty holders have the skills, knowledge, experience and organisational capability (the “SKEO” test)
- Establish how risk assessments and method statements (RAMS) will be version-controlled
- Set the cadence for safety inspections, toolbox talks and worker engagement
- Plan how the Health and Safety File will be compiled and handed over
- Record all decisions in writing — verbal arrangements aren’t evidence
A complete site checklist is exactly the kind of asset HSE inspectors look for during a visit. Print it, digitise it, hand it to your site team — but make sure someone owns it.
Need a ready-to-use version? Download our free CDM 2015 Compliance Checklist — a printable, fillable template covering every duty-holder action above. [Get the checklist →]
Common CDM Compliance Mistakes (And How Digital Tools Help)
The pattern of CDM failures is depressingly consistent. The same handful of mistakes show up across HSE prosecutions year after year:
- No written appointment of principal designer or principal contractor
- Construction phase plan written after work has begun
- Pre-construction information missing or never circulated
- Outdated risk assessments and method statements
- Verbal toolbox talks that are never recorded
- No clear chain for reporting equipment defects or near misses
- Health and safety file never updated, or lost altogether
Most of these failures aren’t about laziness. They’re about paper-based systems collapsing under real site pressure. Documents get lost in vans, forms get signed retrospectively, and version control is impossible across multiple sites.
This is where digital tools change the equation. Pre-use inspections, RAMS templates, defect reports and induction records can all live in one system — timestamped, geo-tagged, instantly retrievable, and impossible to fudge after the fact. When an HSE inspector asks for proof, you produce it from your phone in seconds.
For a closer look at where paper systems quietly cost contractors money, read the real cost of poor safety inspections in construction.
Building a CDM Compliance Routine That Actually Sticks
CDM compliance only works when it becomes routine. The contractors who pass HSE audits effortlessly aren’t smarter — they’ve built habits.
Three principles separate strong compliance cultures from weak ones:
- Compliance lives in the daily rhythm — pre-use inspections, RAMS reviews and toolbox talks happen on schedule, not when an audit looms
- Documentation is automatic — workers record from a phone, not a clipboard, and records sync without anyone re-typing them
- Senior visibility is real — managers see live compliance data, not month-old paper summaries
If you’ve already implemented digital PUWER-compliant equipment checks or site audit software, CDM compliance becomes a layer on top of work you’re already doing — not a separate burden.
Frequently Asked Questions
Is CDM 2015 still in force in 2026?
Yes. The Construction (Design and Management) Regulations 2015 remain the primary UK construction safety legislation. Amendments since 2015 have been minor and procedural; the duty-holder structure and core obligations are unchanged. Always check current HSE guidance (opens in new tab) before relying on this article alone.
Do CDM Regulations Apply to Domestic Clients?
Yes — CDM 2015 applies to domestic clients, but most client duties transfer automatically to the contractor (on single-contractor projects) or principal contractor (on multi-contractor projects) under Regulation 7. Domestic clients still benefit from CDM protection without taking on the full administrative burden of a commercial client.
When Must I Submit an F10 Notification?
You must submit Form F10 to the HSE if a project will last longer than 30 working days with more than 20 workers on site at any one time, or if the project exceeds 500 person-days of work. The client is legally responsible for the submission, but principal contractors often handle it in practice.
What Happens If I Breach CDM 2015?
HSE can issue improvement notices, prohibition notices or pursue criminal prosecution. Penalties range from unlimited fines to imprisonment for the most serious breaches under the Health and Safety at Work etc. Act 1974. Personal liability sits with named directors and duty holders — not just the company.
How Often Should the Construction Phase Plan Be Updated?
The construction phase plan must be reviewed and updated whenever the work, programme or risks change significantly. On long projects that means continuous review — not a single document filed at week one. Treat the CPP as a living plan, not a tick-box, and your construction phase plan will hold up to any HSE audit.
Conclusion: Make CDM 2015 Part of How You Build, Not What You Document
The CDM regulations 2015 aren’t going anywhere. The contractors winning more public-sector tenders, passing HSE audits, and protecting their workers all share one thing: they treat compliance as a daily habit, not a documentation exercise.
Get the duty-holder appointments right at project kick-off. Produce the three core documents (PCI, CPP, H&S file) on time. Keep your records digital, current and traceable. Do those three things consistently and CDM compliance becomes the floor of your safety culture, not the ceiling.
Ready to take the paperwork pain out of CDM compliance? Try WorkMule. Digital inspections, defect reporting, RAMS storage and audit-ready records — all from one app on your team’s phones. [Book a 30-minute demo →]
