The Health and Safety Executive has published updated guidance on the Construction (Design and Management) Regulations 2015, following years of industry feedback that the original L153 guidance left too many questions unanswered — particularly around the role of the principal designer and the practical application of CDM duties on smaller projects.
The new guidance does not change the law — CDM 2015 remains in force as written — but it significantly clarifies how the HSE expects duty holders to interpret and apply their obligations. For principal designers, principal contractors, and contractors working on notifiable projects, the implications are immediate.
What the updated guidance clarifies
Principal designer competence
One of the most contested areas of CDM 2015 has been the competence requirements for principal designers. The original guidance stated that principal designers must have the "skills, knowledge, experience and organisational capability" to carry out the role — but gave little practical guidance on what this meant.
The updated guidance makes clear that the principal designer must have demonstrable experience in managing health and safety during the design phase, not just general design competence. Architects and engineers appointed as principal designers purely on the basis of their design credentials — without specific CDM knowledge — may no longer satisfy the requirement.
Pre-construction information
The updated guidance places renewed emphasis on the quality and completeness of pre-construction information. Clients are reminded that their duty to provide pre-construction information is not discharged by simply forwarding whatever documents happen to be available. The information must be relevant, proportionate to the risks, and provided in a format that contractors can actually use.
For principal contractors, this means scrutinising the pre-construction information they receive and formally requesting additional information where gaps are identified — and documenting that request.
Construction Phase Plan requirements
The guidance reaffirms that a Construction Phase Plan must be prepared before the construction phase begins — not after work has started, not on the first day on site. It also clarifies that the CPP is a live document that must be updated as the project progresses, not a static document produced at the start and filed away.
Specifically, the updated guidance states that the CPP must be reviewed and updated whenever:
- The scope of work changes significantly
- A new contractor or subcontractor comes on site
- A significant incident, near miss, or change in site conditions occurs
- The programme changes in a way that affects the sequencing of high-risk activities
Smaller projects and domestic clients
The updated guidance provides clearer worked examples for smaller projects — including domestic extensions, refurbishments, and fit-outs — where CDM duties still apply but the formal appointment of a principal designer and principal contractor may not be required.
For non-notifiable domestic projects with a single contractor, the guidance confirms that the contractor must still prepare a Construction Phase Plan, carry out suitable and sufficient risk assessments, and ensure welfare facilities are in place before work begins.
What this means for your documentation
The practical implication of the updated guidance is that CDM documentation — particularly the Construction Phase Plan and pre-construction information — will face greater scrutiny from HSE inspectors. Inspectors will be looking for evidence that:
- The CPP was prepared before work started, not retrospectively
- The CPP has been updated to reflect changes on site
- Pre-construction information was reviewed and gaps were formally identified
- The principal designer has demonstrable CDM competence, not just design competence
If your current CPP template was produced years ago and hasn't been reviewed since, now is the time to update it to reflect both the new guidance and the actual conditions on your current projects.
SafetyPod's Construction Phase Plan template is built to the current CDM 2015 requirements and includes all nine sections required by Schedule 3 of the regulations — project description, site management arrangements, welfare, significant risks, site rules, contractor management, permit to work, emergency procedures, and plan review.
Download the Construction Phase Plan template and ensure your CDM documentation is ready for inspection.