The Construction (Design and Management) Regulations 2015 (CDM 2015) are the main set of regulations for managing health and safety in UK construction. They apply to every construction project regardless of size — from a small domestic extension to a major infrastructure scheme. If you carry out construction work in Great Britain, CDM 2015 applies to you.
Many small contractors assume CDM is something for large principal contractors on big projects. That assumption is wrong and can be costly. This guide sets out what CDM 2015 actually requires, who the duty holders are, and what a 2-person contracting business needs to do in practice.
What Is CDM 2015?
CDM 2015 replaced the previous CDM 2007 regulations and came into force on 6 April 2015. The regulations implement the EU Temporary or Mobile Construction Sites Directive (92/57/EEC) into UK law. Post-Brexit, CDM 2015 remains in force in Great Britain under the Health and Safety at Work etc. Act 1974 framework. Northern Ireland has its own equivalent regulations.
The core purpose of CDM 2015 is to ensure that health and safety is considered and managed throughout every stage of a construction project — from design through to completion. The regulations create specific duty holders with defined responsibilities at each stage.
The Five CDM 2015 Duty Holders
1. Client (Regulation 4)
The client is the organisation or individual commissioning the construction work. Clients must make suitable arrangements for managing the project, including ensuring that sufficient time and resources are allocated. Domestic clients (homeowners) have most of their duties transferred to the contractor or principal contractor under Regulation 4(7). Commercial clients retain full CDM duties and cannot transfer them away.
2. Principal Designer (Regulation 11)
Required on projects with more than one contractor. The principal designer is appointed by the client and must plan, manage, monitor and coordinate the pre-construction phase. They must prepare and maintain the health and safety file. This role is typically held by an architect, structural engineer or specialist CDM consultant. On single-contractor projects there is no requirement for a principal designer.
3. Principal Contractor (Regulation 12)
Required on projects with more than one contractor. The principal contractor is appointed by the client and is responsible for planning, managing and coordinating the construction phase. They must prepare and implement the construction phase plan (CPP) before work starts, ensure site induction and supervision, and control access to the site. For a small contractor taking on subcontractors — even one labourer on an occasional basis — this role falls to you.
4. Designer (Regulation 9)
Any person who prepares or modifies a design for a construction project is a designer under CDM 2015. This includes architects, engineers, surveyors — and contractors who design temporary works, formwork, or method statements. Designers must eliminate foreseeable risks during the design stage, and where risks cannot be eliminated, reduce or control them and provide information about remaining risks.
5. Contractor (Regulation 15)
Every contractor on a project has CDM 2015 duties. A contractor is any person or business that carries out, manages or controls construction work. Self-employed individuals are treated as contractors. Contractors must: plan, manage and monitor their own work; ensure workers have appropriate skills, training and experience; provide site induction; and cooperate with other duty holders. These duties apply regardless of whether you are the principal contractor or a subcontractor.
What Small Contractors Actually Need to Do
For a 2-person contractor carrying out typical domestic or small commercial work, here is what CDM 2015 requires in practice:
Risk Assessment (always required)
Even where CDM does not require a formal construction phase plan, you still need a risk assessment under Regulation 3 of the Management of Health and Safety at Work Regulations 1999. This must identify the significant hazards specific to your work — working at height, manual handling, excavation near buried services, use of power tools, COSHH substances — and the control measures you will put in place. Anyrisks generates a compliant risk assessment for your specific job in under 2 minutes.
Construction Phase Plan (when more than one contractor)
If you engage even one subcontractor — a groundworker, an electrician, a plasterer — you become the principal contractor and must prepare a construction phase plan before work starts. The plan does not need to be elaborate for a small project. It should cover: how health and safety will be managed; site rules; welfare arrangements; emergency procedures; and the significant risks specific to the project. The HSE provides guidance in L153 (Managing Health and Safety in Construction).
HSE Notification (F10) — only if the project triggers it
Most small domestic and commercial projects do not require HSE notification. The thresholds under Regulation 6 are: more than 30 working days with more than 20 workers simultaneously on site, or more than 500 person-days total. A 2-person team working for 60 days generates 120 person-days — well below the threshold. Check carefully before assuming notification is required.
Competence
Under Regulation 8, organisations must not appoint a contractor or designer unless they have taken reasonable steps to satisfy themselves that the duty holder has the necessary skills, knowledge, experience and organisational capability to carry out the work safely. As a small contractor, you must be able to demonstrate your own competence — through training records, qualifications, CSCS cards, or equivalent evidence. You must also apply the same check before engaging any subcontractor.
CDM 2015 and Notifiable Projects
When a project is notifiable, the client must notify the HSE using the F10 form at hse.gov.uk before the construction phase begins. The notice must include: the address of the site; name and address of the client; name and address of the principal designer; name and address of the principal contractor; planned start date; and planned duration. The principal contractor must also display a copy of the F10 on site throughout the construction phase.
Health and Safety File
The principal designer must prepare and maintain a health and safety file under Regulation 12(5). The file contains information about the completed structure that is relevant to future construction, maintenance or demolition work — including as-built drawings, information about buried services, materials used, and residual risks. At project completion, the file is handed to the client. On domestic projects the client must be informed it exists and what it contains. The file does not need to be extensive; it must be useful and proportionate to the project.
Penalties for Non-Compliance
CDM 2015 is enforced by the Health and Safety Executive (HSE). Breaches are criminal offences under the Health and Safety at Work etc. Act 1974. The HSE can issue improvement notices, prohibition notices (stopping work immediately), and prosecute. Fines in the Crown Court are unlimited. The HSE’s Fee for Intervention (FFI) scheme means inspectors can charge £163 per hour for time spent investigating material breaches — meaning an inspector visit for a missing construction phase plan could cost several hundred pounds even without prosecution.
In 2023/24, the construction sector accounted for the highest number of fatal injuries to workers of any sector in Great Britain, according to HSE statistics. CDM compliance is not optional: the regulations exist because construction work kills people.
CDM 2015 and Risk Assessments
CDM 2015 does not replace the requirement for risk assessments under MHSWR 1999 — it sits alongside it. Every construction contractor needs a suitable and sufficient risk assessment for their specific work. If you are the principal contractor, your construction phase plan will reference and incorporate the risk assessments for the project. If you are a subcontractor, your own risk assessment must be provided to the principal contractor and comply with any site rules.
Need a compliant construction risk assessment? Anyrisks generates site-specific construction risk assessments in under 2 minutes, covering CDM 2015 duty holder obligations, work at height, manual handling, COSHH, and the specific hazards of your trade.
Related Regulations
CDM 2015 works alongside several other key regulations: the Work at Height Regulations 2005 for any work above ground level; the Control of Substances Hazardous to Health Regulations 2002 (COSHH) for hazardous materials including silica dust, solvents and adhesives; the Manual Handling Operations Regulations 1992 for lifting and carrying; and PUWER 1998 for plant and equipment. A compliant construction phase plan will address all of these.
