The phrase principal designer duties under CDM 2026 is increasingly used in project planning, procurement and tender discussions. However, dutyholders should separate anticipated regulatory change from the law currently in force. At the time of writing, the Construction (Design and Management) Regulations 2015 remain the operative CDM framework. A principal designer appointment must therefore be based on CDM 2015 duties, supported by evidence of competence, effective design-risk management and clear coordination with the client and principal contractor.
For directors, project managers and design managers, the practical issue is not simply whether a future revision may arrive. It is whether the project has a competent principal designer who can control foreseeable risk through design decisions, maintain a defensible pre-construction information process and leave the client with usable health and safety information.
What the principal designer role is intended to achieve
The principal designer is the designer with control over the pre-construction phase. On projects involving more than one contractor, the client must appoint a principal designer in writing as soon as practicable. The appointment should not be treated as an administrative exercise or allocated automatically to the architect, engineer or CDM adviser without examining who genuinely has the authority, resources, knowledge and influence to fulfil the role.
The role is concerned with planning, managing, monitoring and coordinating health and safety during pre-construction. It requires the principal designer to ensure that foreseeable risks are eliminated where reasonably practicable and, where they cannot be eliminated, reduced or controlled through design. The residual risks that remain must be communicated to those who need to manage them during construction, use, maintenance, alteration and eventual demolition.
This distinction matters. A risk register alone does not demonstrate compliance. Neither does a generic set of designer risk assessments issued shortly before tender. Effective coordination means influencing the design while options remain open, challenging assumptions, obtaining missing information and recording why particular risk controls have been selected.
Principal designer duties under CDM 2026: the current legal baseline
Unless and until regulations are formally amended, the baseline remains CDM 2015. Organisations preparing for possible changes should strengthen their existing arrangements rather than pause decisions or rely on unverified interpretations of “CDM 2026”. The core duties expected of a principal designer are already substantial.
Plan, manage, monitor and coordinate pre-construction health and safety
The principal designer must establish a proportionate process for design-risk management. This starts by identifying the scope, interfaces and constraints of the project. On a civils scheme, for example, this may include existing services, ground conditions, temporary works dependencies, traffic management, contaminated land and access for future inspection. On an occupied refurbishment, it can include asbestos information, fire compartmentation, operational constraints, hidden services and phased handovers.
Coordination must reach every relevant designer, including specialist subcontractors undertaking design, temporary works designers, MEP designers, façade specialists and manufacturers providing design input. The principal designer should define how information will be issued, reviewed and closed out. Design meetings should have a health and safety agenda that records decisions, actions, ownership and due dates.
The process should be proportionate. A straightforward internal fit-out does not require the same governance as a complex energy, utilities or infrastructure project. Yet both require evidence that risks have been considered at the point design decisions are made.
Help the client provide suitable pre-construction information
The client must provide pre-construction information that is relevant, proportionate and sufficiently detailed for designers and contractors. The principal designer has a key role in advising what information is required, reviewing what has been supplied and identifying material gaps.
Useful information can include surveys, existing drawings, ground investigation data, asbestos registers, utilities records, fire strategy information, structural details, environmental constraints and records of previous alterations. For excavation work, records should be tested against the requirements of HSG47 rather than accepted uncritically. A statutory undertaker search or an old service drawing does not establish the precise position and depth of live apparatus.
Where information is absent or unreliable, the principal designer should make the residual uncertainty visible. This may require intrusive surveys, trial holes, scanning, specialist inspections or clear design assumptions that are then carried into construction planning. Concealed uncertainty is a recurring cause of programme pressure, unsafe improvisation and claims.
Ensure designers meet their own CDM duties
Every designer has duties under CDM 2015. They must take account of the general principles of prevention, eliminate or reduce foreseeable risks, and provide information about significant residual risks. The principal designer coordinates this activity but does not absorb every designer’s legal responsibility.
A competent principal designer will set expectations early. That normally means agreeing design deliverables, risk-review gateways, document control requirements and escalation routes. It also means testing the quality of submissions. Statements such as “contractor to assess” or “use suitable access equipment” are often too vague where the design itself could remove the hazard or prescribe a safer permanent solution.
Design risk should be specific to the asset and the task. For example, specifying roof-mounted plant without safe access, edge protection strategy, lifting provision and maintenance space pushes foreseeable risk downstream. Similarly, locating isolation points in inaccessible areas may create an operational safety issue long after practical completion.
Liaise with the principal contractor and support the construction phase plan
Pre-construction and construction cannot be managed as separate silos. The principal designer must liaise with the principal contractor and share information relevant to the construction phase plan. This is particularly important where design development continues after works begin, where there are temporary works interfaces, or where the site programme changes the sequence of risk.
The principal contractor owns the construction phase plan and site controls. The principal designer should not duplicate that role. Their value lies in ensuring that design assumptions are understood, residual risks are not lost during handover and late design changes are reviewed for their construction and operational consequences.
A formal design handover is often worthwhile on larger schemes. It can confirm outstanding design matters, significant residual risks, survey limitations, temporary works considerations, client decisions and information needed for the health and safety file.
Prepare, review and hand over the health and safety file
The health and safety file is for the client and those undertaking future work on the structure. It should contain information needed to plan, manage and carry out foreseeable work safely. It is not a dumping ground for every drawing, operation and maintenance manual, RAMS document or site record produced during the project.
The principal designer should establish the file structure at the outset, identify contributors and set information requirements. The file must be kept under review as the project develops, then handed to the client at completion. For phased projects, it should be updated at each meaningful handover rather than deferred until the final package, when missing information is harder to retrieve.
Competence, organisational capability and appointment risk
CDM requires appointments to be made only where the appointee has the necessary skills, knowledge, experience and organisational capability. For a principal designer, this is broader than holding a qualification or having attended a CDM course. The appointee needs sufficient technical understanding of the project, authority to challenge design decisions, access to specialist advice and administrative capacity to control information.
A design practice may be well placed to act where it leads the design and has appropriate CDM capability. A specialist CDM adviser may be better placed on a complex programme where coordination crosses multiple disciplines, packages and workstreams. In some cases, a hybrid arrangement can work, but the legal appointment must remain unambiguous. Clients should avoid arrangements in which the named principal designer has no meaningful influence while another party makes the critical design decisions.
Procurement should test capability through project-relevant evidence: comparable schemes, governance arrangements, competence of named personnel, escalation procedures, information-management methods and capacity to attend key design reviews. Fee pressure is not a justification for a nominal appointment. Under-resourced coordination commonly produces incomplete pre-construction information, poorly controlled changes and weak health and safety files.
Preparing for any CDM reform without creating uncertainty
If CDM changes are introduced in the future, projects will need to review the final regulations, transitional provisions and associated HSE guidance. Until then, businesses should avoid rewriting their systems around speculation. A stronger approach is to audit current CDM arrangements against the practical behaviours that regulators and clients already expect.
This includes written appointments made early, a clear client brief, coordinated pre-construction information, scheduled design-risk reviews, controlled change management, and a health and safety file developed throughout the project. For higher-risk work, the process should also interface properly with fire strategy, DSEAR assessments, environmental constraints, temporary works procedures and asset-management requirements.
Evolution Safety Solutions can support clients and design teams with CDM 2015 principal designer services, pre-construction information reviews, design-risk workshops, health and safety file development and competence-focused training. The objective is not paperwork for its own sake. It is a controlled record of decisions that enables safer construction and safer future work.
A well-run principal designer function gives the project team a practical test for every major design decision: has the risk been removed at source, reduced through the design, communicated to the right dutyholder and recorded for the asset’s future life? Keeping that question active from concept through to handover is the most reliable preparation for both current duties and any future regulatory change.