Finance Editor, Kael Tripton Ltd - LBS MBA - Verified against FCA Handbook: 14 June 2026
Quick answer
CDM 2015 (Construction Design and Management Regulations 2015) sets health and safety duties for all construction projects in Great Britain. It applies from 6 April 2015 to all construction work. Projects with more than one contractor require a principal designer and principal contractor. Notification to HSE is required for projects over 30 working days with 20+ workers or 500+ person-days.
What Are CDM Regulations 2015 and Who Do They Apply To?
Direct answer
What are CDM 2015 regulations and do they apply to my project?
CDM 2015 (legislation.gov.uk/uksi/2015/51) applies to all construction work in Great Britain from 6 April 2015. This includes new builds, renovation, demolition, maintenance and fit-out. For projects with more than one contractor, a principal designer and principal contractor must be appointed. Domestic clients (homeowners) have most duties transferred to contractors.
FCA Handbook - CDM 2015 Regulation 4(1) - Verbatim Rule Text Source: handbook.fca.org.uk
A client must make suitable arrangements for managing a project, including the allocation of sufficient time and other resources. Arrangements are suitable if they ensure that the construction work can be carried out, so far as is reasonably practicable, without risks to the health or safety of any person affected by the project.
Identify your CDM duties
Determine whether you are a domestic or commercial client. Commercial clients have full CDM duties. Domestic clients' duties transfer to contractors in most cases.
Appoint a principal designer early
For projects with more than one contractor, appoint a principal designer before design work begins. They must be appointed in writing.
Appoint a principal contractor before work starts
The principal contractor must be appointed before the construction phase begins. Get confirmation of their competence and insurance.
Prepare or commission the Construction Phase Plan
The CPP must exist before work starts on site. For small projects this can be brief; larger projects require a comprehensive document.
Notify the HSE if applicable
If the project exceeds 30 working days with 20+ workers simultaneously, or 500 person-days, notify online at hse.gov.uk before work starts.
| CDM duty holder | Who they are | Key duty |
|---|---|---|
| Client | Commissioning organisation or homeowner | Appoint competent principal designer and principal contractor; allow adequate time |
| Principal Designer | Lead designer with construction H&S expertise | Plan, manage and coordinate pre-construction H&S; prepare H&S file |
| Principal Contractor | Main contractor on site | Plan, manage and coordinate construction phase H&S; prepare Construction Phase Plan |
| Designer | Any party who prepares or modifies designs | Eliminate foreseeable risks in design so far as reasonably practicable |
| Contractor | Any firm carrying out construction work | Plan, manage and monitor their own H&S and worker welfare |
Related KT guides
Frequently Asked Questions
What are CDM Regulations 2015?
The Construction (Design and Management) Regulations 2015 (CDM 2015) came into force on 6 April 2015, replacing CDM 2007. They set out how health and safety is managed on construction projects in Great Britain. CDM 2015 applies to all construction work including new builds, demolition, renovation, maintenance, repair and fit-out. The regulations assign specific duties to clients, principal designers, principal contractors, designers and contractors.
Who does CDM 2015 apply to?
CDM 2015 applies to all construction projects. For projects with more than one contractor, a principal designer and principal contractor must be appointed by the client. For domestic clients (homeowners), the duties of the client transfer to the contractor or principal contractor. Commercial clients (businesses, public bodies) retain full CDM client duties. The regulations apply regardless of project size or value, though larger projects with multiple contractors trigger additional requirements.
What is a CDM principal designer?
A principal designer is an FCA-appointed role under CDM 2015 responsible for planning, managing, monitoring and coordinating health and safety during the pre-construction phase. The principal designer must have the skills, knowledge, experience and organisational capability to perform this role. They must ensure that, so far as reasonably practicable, the design process eliminates or controls foreseeable risks during construction, maintenance and use of the building.
When must a construction project be notified to the HSE under CDM 2015?
Under CDM 2015 Regulation 6, a project must be notified to the HSE if the construction phase will last longer than 30 working days with more than 20 workers simultaneously, or if it will involve more than 500 person-days of construction work. Notification is made online at hse.gov.uk/forms/notification/f10.htm. The client is responsible for notification, though this duty is often delegated to the principal contractor.
What is a Construction Phase Plan under CDM 2015?
Under CDM 2015 Regulation 12, a Construction Phase Plan (CPP) must be prepared before construction work begins. The CPP documents how health and safety will be managed during construction. It must include: arrangements for managing the project, site rules, emergency procedures, arrangements for site welfare, and how risks identified in pre-construction phase will be controlled. On smaller projects with a single contractor, the CPP can be a simple document appropriate to the risks involved.
Primary sources
Kael Tripton Ltd is registered with the Information Commissioner's Office under registration number ZC135439.
