The Principal Designer is one of the five key duty holder roles under the CDM Regulations 2015. They coordinate health and safety during the pre-construction phase of notifiable projects, working with the client and design team to eliminate or reduce risks before construction work begins.
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What is a Principal Designer?
The Principal Designer is a designer appointed by the client on notifiable projects to plan, manage, monitor and coordinate health and safety in the pre-construction phase.
The role was introduced in the CDM Regulations 2015, replacing the previous CDM Coordinator role. Unlike the CDM Coordinator, the Principal Designer must be a designer themselves — someone with skills, knowledge and experience in both design and construction health and safety.
The Principal Designer isn't just a coordinator or administrator. They're an active member of the design team with the expertise to identify design risks and influence design decisions to improve construction health and safety.
Key functions of the Principal Designer
The Principal Designer has three primary functions:
- Plan, manage and coordinate health and safety during the pre-construction phase — ensuring designers work together to eliminate or reduce risks
- Help the client gather and provide pre-construction information — identifying existing risks that affect design decisions
- Prepare the health and safety file — creating a record of information for future construction work
The Principal Designer acts as the focal point for health and safety during design development, working closely with:
- The client
- All designers (architects, engineers, specialist designers)
- The Principal Contractor (once appointed)
- Specialists and consultants
When is a Principal Designer required?
A Principal Designer must be appointed on notifiable projects only.
A project is notifiable if the construction work is expected to:
- Last more than 30 working days and involve more than 20 workers at any point, OR
- Exceed 500 person days of work (e.g., 10 workers for 50 days)
Appointment timing
The client must appoint the Principal Designer as soon as practicable after the client knows enough about the project to be able to appoint them.
In practice, this is usually:
- At the same time as appointing the initial design team
- Before significant design work begins
- Early enough that they can influence key design decisions
Appointing a Principal Designer late in the design process significantly reduces their ability to influence safety outcomes. Early appointment is essential for effective risk elimination and reduction.
When the appointment ends
The Principal Designer's appointment normally ends when the construction phase finishes. However, they may continue if:
- There's design work continuing after construction (e.g., remedials, variations)
- The client wants them to oversee completion of the health and safety file
The Principal Designer role can also be transferred to the Principal Contractor in certain circumstances (see below).
Who can be appointed as Principal Designer?
The Principal Designer must be:
- A designer — an organisation or individual that prepares or modifies designs as part of their role
- Competent — having the necessary skills, knowledge, training and experience
- Adequately resourced — able to dedicate sufficient time and resources to fulfil the role
Designer qualification
The CDM Regulations define a designer as anyone who:
- Prepares or modifies designs
- For a structure
- In connection with construction work
This includes:
- Architects
- Structural engineers
- Building services engineers
- Civil engineers
- Architectural technologists
- Design consultants
- Quantity surveyors (when specifying materials/systems)
It does NOT include:
- Pure project managers (unless they also design)
- Health and safety consultants (unless they're also designers)
- Contractors acting solely as contractors (unless they also design)
A common mistake is appointing a health and safety consultant as Principal Designer. Unless they're also a designer with genuine design responsibilities on the project, they cannot legally hold the role.
Competence requirements
The Principal Designer must demonstrate competence in:
Design knowledge:
- Understanding of design processes and construction methods
- Ability to identify how design decisions affect construction health and safety
- Knowledge of buildability, maintainability and demolition issues
Construction health and safety knowledge:
- Understanding of construction hazards and risk management
- Knowledge of CDM Regulations and other relevant legislation
- Awareness of industry standards and good practice
Project management skills:
- Ability to plan and coordinate multiple designers
- Communication skills to influence design decisions
- Capability to manage information and prepare documentation
Proportionate experience:
- Experience appropriate to the size and complexity of the project
- Track record of similar projects
- Understanding of the specific risks relevant to the project type
Can an individual or organisation be appointed?
Either an individual or an organisation can be appointed as Principal Designer.
Individual appointment:
- A named person takes on the role and duties
- Common on smaller projects with limited design team
- Individual must have adequate PI insurance and resources
Organisation appointment:
- A company or firm is appointed and assigns staff to fulfil the role
- The organisation remains legally responsible even if individuals change
- Common on larger projects requiring team input
When appointing an organisation, ensure they've designated a specific individual as the day-to-day contact. This ensures accountability and clear communication channels.
Principal Designer duties
The Principal Designer has specific duties set out in Regulation 11 of CDM 2015.
1. Plan, manage, monitor and coordinate health and safety in the pre-construction phase
The Principal Designer must:
- Develop a strategy for managing health and safety during design
- Coordinate all designers to ensure they fulfil their duties
- Hold design team meetings to discuss health and safety
- Review design information to identify risks and opportunities for improvement
- Challenge design decisions that create unnecessary risks
- Ensure cooperation between designers working on different elements
- Monitor progress and ensure design risks are being addressed
This isn't a passive role. The Principal Designer actively drives the design team to eliminate hazards and reduce risks.
Good Principal Designers don't just review completed designs — they participate in design development, asking questions like "Can we design this out?" and "How will this be built, maintained, and eventually demolished?"
2. Help and advise the client in bringing together pre-construction information
Pre-construction information is information about the site and existing structures that designers and contractors need to identify and manage risks.
The Principal Designer must:
- Help the client identify what information is needed
- Advise on sources of information (surveys, records, previous files)
- Gather information from the client and other sources
- Review and compile information into a usable format
- Provide information to designers and contractors when needed
- Update information as more becomes available
Examples of pre-construction information:
- Asbestos surveys and registers
- Ground conditions and contamination reports
- Location of existing services (utilities, drainage)
- Structural information about existing buildings
- Previous health and safety files
- Site access and restrictions
- Traffic management requirements
- Environmental constraints
3. Identify, eliminate or control foreseeable risks
Working with the design team, the Principal Designer must ensure:
- Hazards are eliminated where reasonably practicable (e.g., specifying prefabricated components instead of site assembly at height)
- Risks are reduced through design decisions (e.g., designing permanent edge protection)
- Remaining risks are identified and communicated to those who need to know
- Design decisions are recorded including health and safety considerations
This follows the hierarchy of risk control:
- Eliminate the hazard entirely
- Reduce the risk through design
- Provide information about remaining risks
Design eliminates work at height risk
A warehouse refurbishment required replacement of high-level lighting across 5,000 square metres of ceiling space. Original specification called for traditional fixtures requiring regular bulb replacement via mobile elevated work platforms.
- ✓Principal Designer challenged the lighting design during coordination meetings
- ✓Structural engineer confirmed ceiling structure could support alternative systems
- ✓Design team specified long-life LED systems with 20-year warranty
- ✓Lighting mounted on ceiling surface rather than suspended (no fragile roof access)
- ✓Eliminated annual maintenance work at height for the life of the building
- ✓Reduced whole-life costs despite higher initial capital expenditure
The design change eliminated over 1,000 hours of work at height over the building's anticipated lifespan. Initial cost increase of £15,000 resulted in maintenance savings exceeding £150,000.
Challenging design assumptions early in the process can eliminate entire categories of risk. The Principal Designer's role in coordinating this discussion between disciplines was essential.
4. Ensure designers carry out their duties
All designers have duties under Regulation 9 of CDM 2015. The Principal Designer must:
- Check designers understand their CDM duties
- Ensure design information includes health and safety considerations
- Review design outputs to confirm risks have been addressed
- Raise concerns when designers aren't fulfilling their duties
- Report persistent failures to the client
The Principal Designer isn't responsible for the detailed design work itself, but they must ensure designers are considering health and safety in their work.
5. Liaise with the Principal Contractor
Once appointed, the Principal Contractor needs information from the design team to prepare the Construction Phase Plan.
The Principal Designer must:
- Provide relevant information about design risks and how they should be managed
- Explain design intent and critical health and safety aspects
- Respond to queries about buildability and design details
- Coordinate design changes during construction
- Maintain communication throughout the construction phase
This liaison continues throughout the project, particularly when design changes occur during construction.
6. Prepare the health and safety file
The health and safety file is a record of information for the client about significant health and safety risks that must be managed during future work.
The Principal Designer must:
- Plan the file structure early in the project
- Gather relevant information from designers and contractors
- Review and edit information to ensure it's clear and useful
- Keep the file updated as the project develops
- Hand over the completed file to the client at project completion
The file should focus on information needed for future construction work — maintenance, refurbishment, and eventual demolition.
What to include:
- As-built drawings showing critical structural information
- Information about hazardous materials (asbestos, lead, specialist coatings)
- Details of services and buried utilities
- Structural principles and load-bearing elements
- Access requirements for maintenance
- Specific risks (confined spaces, fragile surfaces)
- Removal or dismantling requirements
What NOT to include:
- Construction phase plans (unless relevant to future work)
- Project management paperwork
- Routine maintenance schedules with no specific safety implications
- Generic health and safety policies
The health and safety file should be concise and practical. A 50-page file that people will actually use is far more valuable than a 500-page file that will sit on a shelf. Quality over quantity.
7. Provide information to other duty holders
The Principal Designer must ensure relevant information is provided to:
- The client — about risks, progress, and any issues requiring client decisions
- Designers — pre-construction information and coordination requirements
- The Principal Contractor — design information needed for the Construction Phase Plan
- Contractors — information about specific design risks and requirements
Information must be provided at the right time, in a usable format, and to the people who need it.
Principal Designer duties checklist
- Agree appointment terms, responsibilities and resources with client
- Help client identify and gather pre-construction information
- Establish coordination arrangements for the design team
- Hold design coordination meetings focused on health and safety
- Review design information and challenge decisions creating unnecessary risks
- Ensure all designers understand and fulfil their CDM duties
- Maintain a design risk register or similar record
- Ensure design information includes residual risks
- Plan the health and safety file structure and content
- Liaise with Principal Contractor once appointed
- Provide information for Construction Phase Plan
- Respond to design queries during construction
- Coordinate design changes and their health and safety implications
- Gather information from contractors for health and safety file
- Complete and hand over health and safety file to client
These duties apply throughout the project, not just at the start. The Principal Designer's role is ongoing until the construction phase is complete and the health and safety file is handed over.
Relationship with other duty holders
The Principal Designer works closely with all other duty holders throughout the project.
With the client
- Advises the client on designer appointments and competence
- Reports on progress and any issues affecting health and safety
- Requests information needed from the client
- Escalates problems when design risks can't be resolved
- Provides the health and safety file at completion
The client can't transfer their duties to the Principal Designer, but the Principal Designer helps the client fulfil them.
With designers
- Coordinates design activities to ensure health and safety is considered
- Shares pre-construction information so designers can identify site-specific risks
- Reviews design outputs to confirm risks are being addressed
- Facilitates cooperation between different design disciplines
- Ensures design information includes residual risk details
The Principal Designer doesn't do the designers' work for them, but ensures designers understand and fulfil their duties.
With the Principal Contractor
- Hands over information about design risks and how to manage them
- Explains design intent and critical safety aspects
- Responds to buildability concerns and construction queries
- Coordinates design changes during construction
- Gathers information from the Principal Contractor for the health and safety file
Effective liaison between Principal Designer and Principal Contractor is essential for a smooth transition from pre-construction to construction phase.
With contractors
While the Principal Contractor is the main interface with contractors, the Principal Designer may:
- Provide specialist design information directly to contractors when needed
- Explain design requirements for particular elements
- Review contractor design (temporary works, specialist installations)
- Gather information about installed systems for the health and safety file
Principal Designer vs Principal Contractor
Principal Designer
- •Coordinates pre-construction phase
- •Manages design team health and safety
- •Must be a designer themselves
- •Prepares health and safety file
- •Focuses on design risk management
- •Works mainly with design team
Principal Contractor
- •Coordinates construction phase
- •Manages site health and safety
- •Must be a contractor
- •Prepares Construction Phase Plan
- •Focuses on construction risk management
- •Works mainly with site workforce
Bottom line: Both roles coordinate their respective phases of the project. Effective handover and ongoing liaison between them is critical for project safety.
Principal Designer vs Designer
All designers have duties under CDM 2015. So what's the difference between a designer and the Principal Designer?
Designer duties (Regulation 9)
Every designer must:
- Eliminate hazards and reduce risks in their designs
- Provide information about remaining risks
- Cooperate with other designers and duty holders
- Not start work unless satisfied the client is aware of their duties
These duties apply to all designers on all projects, whether notifiable or not.
Principal Designer duties (Regulation 11)
The Principal Designer has additional duties to:
- Plan, manage and coordinate the health and safety work of the design team
- Ensure all designers fulfil their duties
- Help the client gather pre-construction information
- Prepare the health and safety file
These coordination duties only apply on notifiable projects where a Principal Designer has been appointed.
The Principal Designer doesn't replace individual designers' duties — they coordinate and ensure those duties are being fulfilled. All designers remain responsible for eliminating risks in their own designs.
On non-notifiable projects
Small projects that aren't notifiable don't require a Principal Designer appointment. But someone still needs to:
- Coordinate design decisions affecting health and safety
- Ensure design information is passed to contractors
- Prepare a health and safety file (if work could affect future construction)
Typically, the lead designer takes on these responsibilities informally.
Principal Designer vs CDM Coordinator (old regulations)
The Principal Designer replaced the CDM Coordinator role when CDM 2015 came into force. While there are similarities, there are important differences.
How they're similar
Both roles:
- Are appointed by the client on notifiable projects
- Coordinate health and safety during design
- Prepare the health and safety file
- Liaise between client, designers and contractors
How they're different
CDM Coordinator vs Principal Designer
CDM Coordinator (old role)
- •Could be anyone competent in CDM
- •Often a health and safety consultant
- •Mainly an advisory and coordination role
- •Not necessarily involved in design decisions
- •Sometimes seen as 'CDM police'
- •Often appointed late in design process
Principal Designer (current role)
- •Must be a designer
- •Must have design responsibilities on the project
- •Active member of the design team
- •Expected to influence design decisions
- •Integrated into design process
- •Should be appointed at project start
Bottom line: The Principal Designer is more embedded in the design process and has greater ability to influence safety outcomes through design. The role is less about policing compliance and more about achieving safe design.
Why the change was made
The CDM Coordinator role had limitations:
- Often appointed too late to influence key design decisions
- Sometimes lacked technical design knowledge
- Could be seen as an external 'checker' rather than part of the team
- Variable understanding of the role across the industry
The Principal Designer role addresses these issues by:
- Requiring design expertise and involvement
- Encouraging early appointment
- Integrating health and safety into design team activities
- Clarifying the active, coordinating nature of the role
If you worked with a CDM Coordinator on projects before 2015, think of the Principal Designer as similar but more embedded in the design team and with greater expectations around design risk management.
When the role can be passed to the Principal Contractor
In some circumstances, the Principal Designer role can be transferred to the Principal Contractor.
When transfer is appropriate
Transfer may be suitable when:
- Design work is substantially complete before construction starts
- No significant design changes are expected during construction
- The Principal Contractor is competent in both contracting and design coordination
- All parties agree to the transfer
The client, outgoing Principal Designer, and incoming Principal Contractor must all agree and understand the implications.
When transfer is NOT appropriate
Transfer should not happen when:
- Design work is ongoing during construction
- Significant design changes are anticipated
- The Principal Contractor lacks design competence or resources
- Design coordination requires specific technical expertise
Transferring the Principal Designer role to avoid costs or reduce coordination effort is not appropriate. The transfer must be based on genuine project circumstances and the Principal Contractor's competence.
What happens on transfer
When the role transfers:
- The client formally appoints the Principal Contractor as Principal Designer
- The outgoing Principal Designer hands over all relevant information and the partially completed health and safety file
- The Principal Contractor takes on all Principal Designer duties for the remainder of the project
- The same organisation cannot be both Principal Designer and Principal Contractor — if they were only Principal Contractor, they now hold both roles merged into one coordinating function
The transfer should be documented, and the HSE should be notified if the F10 notice needs updating.
Design and build projects
On design and build projects where the contractor is responsible for design:
- A Principal Designer must still be appointed if the project is notifiable
- The contractor often appoints a design consultant or architect as Principal Designer
- As design completes, the role commonly transfers to the main contractor
- This allows single-point coordination once most design is fixed
Competence assessment: Appointing a Principal Designer
Clients must check that the Principal Designer they appoint is competent and adequately resourced.
Checking competence
Ask about:
Qualifications and memberships:
- Professional qualifications in relevant design discipline
- Membership of professional bodies (RIBA, RICS, ICE, etc.)
- CDM training and qualifications
Experience:
- Similar projects in size, complexity and type
- Track record of Principal Designer appointments
- Specific experience relevant to your project risks
Knowledge:
- Understanding of design processes
- Knowledge of construction methods and sequencing
- Awareness of CDM duties and responsibilities
- Understanding of relevant health and safety legislation
Resources:
- Staff with appropriate skills available for the project
- Time allocated to fulfil the role
- Professional indemnity insurance adequate for the project
- Systems for managing design coordination and information
Red flags
Be cautious if:
- They're not a designer or have no design responsibilities on the project
- They have no relevant project experience
- They're unclear about what the role involves
- They can't explain how they'll coordinate the design team
- They're being appointed very late in the design process
- They quote fees that seem too low for the work involved
Checking resources
Ensure:
- Sufficient time is allocated (proportionate to project size and complexity)
- Named individuals are assigned to the role
- They have access to specialist input if needed (structural, fire, CDM)
- Professional indemnity insurance covers Principal Designer duties
For smaller projects, the lead designer (architect or engineer) is often the natural choice for Principal Designer. They already understand the project and have the relationships needed to coordinate the design team.
Common Principal Designer mistakes
1. Appointing a non-designer
The most common mistake is appointing someone who isn't actually a designer. Health and safety consultants, project managers, and CDM advisers cannot be Principal Designer unless they also have genuine design responsibilities on the project.
Solution: Appoint someone from the design team — architect, engineer, or another design professional.
2. Late appointment
Appointing the Principal Designer after key design decisions have been made limits their ability to eliminate hazards through design.
Solution: Appoint at the same time as the initial design team, before RIBA Stage 2 (Concept Design) or equivalent.
3. Treating it as a box-ticking role
Some Principal Designers focus on paperwork and compliance rather than actively influencing design decisions to improve safety.
Solution: The Principal Designer should attend design team meetings, review design options, and challenge decisions that create unnecessary risks.
4. Not coordinating the design team
Failing to establish regular coordination meetings or communication channels means design risks aren't discussed and coordinated.
Solution: Set up design coordination meetings with health and safety as a standing agenda item. Circulate meeting notes and action points.
5. Creating a massive health and safety file
Dumping all project information into the health and safety file makes it unusable. Future users need concise, relevant information.
Solution: Be selective. Focus on information needed for future construction work, not general project records.
6. Not liaising with the Principal Contractor
Failing to share design information with the Principal Contractor means they can't adequately plan for construction risks.
Solution: Arrange handover meetings before construction starts. Establish ongoing communication channels for design queries and changes.
7. Thinking the role ends at construction start
The Principal Designer's duties continue through construction — responding to queries, coordinating design changes, updating the health and safety file.
Solution: Allocate time and resources for the full project duration, not just the pre-construction phase.
Frequently asked questions
Only if they're also a designer with design responsibilities on the project. The CDM Regulations require the Principal Designer to be a designer — someone who prepares or modifies designs. A health and safety consultant who only provides advice and doesn't design cannot legally be appointed as Principal Designer.
Fees vary based on project size, complexity and duration. As a rough guide, Principal Designer fees typically range from 0.5% to 2% of construction costs for most projects, or a time-based fee reflecting the effort required. Very small projects might be a fixed fee of £2,000-£5,000. Large complex projects may justify higher percentages. Suspiciously low fees suggest inadequate time will be allocated.
Yes, and this is common on many projects. Architects are designers and often have good knowledge of construction health and safety. However, ensure they have adequate CDM competence, understand the role's requirements, and can allocate sufficient time beyond their normal architectural duties.
On notifiable projects, if the client fails to appoint a Principal Designer, the client automatically becomes the Principal Designer and takes on all the associated duties. This is rarely practical, as clients typically lack the design expertise and construction health and safety knowledge required. It's a breach of CDM regulations and the HSE can take enforcement action.
No. CDM 2015 specifically prohibits the same organisation being both Principal Designer and Principal Contractor at the same time. This is to maintain separation between design coordination and construction coordination. However, an organisation can be a designer and a contractor, and the Principal Designer role can be transferred to the Principal Contractor if appropriate.
If the domestic project is notifiable (over 30 days or 500 person days), yes. However, the domestic client's duties — including appointing the Principal Designer — automatically transfer to either the contractor (non-notifiable) or the Principal Designer/Principal Contractor (notifiable). In practice, the contractor takes responsibility for making these appointments on behalf of the domestic client.
As soon as practicable after the client knows enough about the project. In practice, this means at the start of the design process — typically when appointing the initial design team. Appointing late reduces the Principal Designer's ability to eliminate hazards through design. Early appointment is essential for effective risk management.
The CDM Coordinator was the old role under CDM 2007, replaced by the Principal Designer in CDM 2015. The key difference is that the Principal Designer must be a designer with design responsibilities, whereas the CDM Coordinator could be anyone competent in CDM. The Principal Designer is more embedded in the design process and expected to actively influence design decisions.
Yes, but only if they're also acting as a designer on the project. Contractors who prepare designs (for example, in design-and-build projects or when designing temporary works) are designers. However, a contractor acting purely as a contractor with no design responsibilities cannot be appointed as Principal Designer.
There are no mandatory qualifications. However, the Principal Designer should have: relevant design qualifications (architect, engineer, etc.), CDM training, experience of similar projects, and knowledge of construction health and safety. Professional membership (RIBA, RICS, ICE, etc.) and specific CDM certifications (NEBOSH Construction Certificate, etc.) demonstrate competence.
Resources and further guidance
Official guidance:
- HSE: Managing health and safety in construction (L153) — The official guidance on CDM 2015
- HSE: Principal Designer responsibilities
Assessing competence:
- Check professional body membership and standing
- Request case studies of similar projects
- Ask about their approach to design coordination
- Ensure adequate professional indemnity insurance
Professional bodies:
- RIBA (Royal Institute of British Architects)
- RICS (Royal Institution of Chartered Surveyors)
- ICE (Institution of Civil Engineers)
- IStructE (Institution of Structural Engineers)
- Association for Project Safety (APS)
Next steps
Want to understand all the CDM duty holder roles?
What is CDM? Construction (Design and Management) Regulations explained →
Need to know if your project requires CDM appointments?
Do I need CDM? Project size and duty requirements →
Understanding what goes in the health and safety file?
Health and Safety File: What to include and why it matters →
Not sure who to appoint as Principal Designer or whether they're competent? A CDM specialist can review your project requirements, assess potential appointees, and advise on your specific situation.
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