Why the CDM Principal Designer Role Is Becoming Clearer – and What This Means in Practice

The Health and Safety Executive is expected to provide further clarification about how the CDM Principal Designer role under the Construction (Design and Management) Regulations 2015 should be applied, with additional guidance expected following its review of how CDM 2015 is working in practice.

At Richardson-Hill, the need for greater clarity comes as no surprise. It is rare for us to advise a client on a Principal Designer appointment without some version of the same question arising: which Principal Designer, responsible for what, and how does that appointment relate to the Building Regulations Principal Designer role introduced through the amended Building Regulations in 2023?

Why the CDM Principal Designer Role Needed Clarifying in the First Place

Under CDM 2015, a client must appoint a CDM Principal Designer in writing whenever a project involves, or is likely to involve, more than one contractor. On paper, that is a simple trigger. In practice, we regularly see clients who are unsure whether it applies to their project at all, or who treat the appointment as a formality rather than a substantive role.

The Principal Designer’s actual job is to lead the planning, management, monitoring and coordination of health and safety throughout the pre-construction phase. This includes helping to assemble pre-construction information, coordinating designers and making sure foreseeable risks are eliminated or, where that is not reasonably practicable, reduced or controlled before work starts on site.

Done properly, it is one of the most effective tools available for managing risk early, when changes are generally more practicable and less costly to make. Treated as a paperwork exercise, it achieves very little.

That gap between the CDM Principal Designer role as written and the role as practised is, in our experience, precisely why clearer guidance has become necessary.

Where Further Clarification Is Still Needed

Based on the findings of the CDM post-implementation review and subsequent industry reporting, several areas appear likely to receive further attention:

• The importance of appointing the Principal Designer early enough to influence significant design decisions
• Clearer expectations of clients and other CDM duty holders
• Better ways of assessing whether an individual or organisation has the skills, knowledge, experience and organisational capability required for a particular project
• More consistent systems for preparing, maintaining and sharing project information
• Practical, proportionate guidance that smaller businesses can apply to everyday projects

Each of these areas maps directly onto the questions we field most often from clients.

Early appointment and pre-construction complexity arise on almost every project where the Principal Designer is brought in after important concept design decisions have already been made. By that point, the opportunity to eliminate or reduce risks through design may already be limited.

Client obligations and Principal Designer competence become particularly important when a client is choosing whom to appoint but is unsure what suitable skills, knowledge, experience and organisational capability should look like for that particular project.

More consistent information management also matters. Pre-construction information is only useful if it is accurate, maintained and readily accessible to the people who need it. Unfortunately, a large collection of documents does not necessarily represent effective information management if important risks are difficult to identify or the information is not being shared with the appropriate duty holders.

Proportionate guidance for SMEs is equally important because many of the organisations involved in delivering construction projects are smaller businesses, for whom generic guidance does not always translate easily into everyday decisions.

Two Roles, One Similar Name

One of the most persistent sources of confusion we encounter is the existence of two Principal Designer roles that share a title but not a purpose.

The CDM Principal Designer manages and coordinates health and safety risk during the pre-construction phase under CDM 2015. Its responsibilities encompass risks that may arise during construction, maintenance, use, alteration and eventual demolition.

The Building Regulations Principal Designer has a different function: planning, managing, monitoring and coordinating design work so that, if the building work is carried out as designed, it complies with the Building Regulations.

One organisation can hold both appointments if it has the competence and capability required for each. We undertake both roles for some clients, but taking on both appointments does not merge them or reduce either set of duties.

We always advise making the scope of each appointment explicit in the contract documents. It should be clear which function is being carried out, what it covers and how the two roles will be coordinated. Ambiguity here is one of the more common causes of gaps in accountability that we are asked to help untangle after the event.

What We Advise Clients to Do Now

Further guidance from the HSE should help, but it will not retrospectively correct a poorly managed appointment. The existing requirements of CDM 2015 are already in force and clients should not delay taking action while waiting for additional clarification.

Before design work progresses too far, we typically advise clients to:

• Confirm early whether the project will involve, or is likely to involve, more than one contractor
• Make the CDM Principal Designer appointment in writing as early as practicable – ideally during the concept stage
• Check that the proposed appointee’s skills, knowledge, experience and organisational capability genuinely match the project’s scale, complexity and risk profile
• Give the Principal Designer sufficient time, information and resources to perform the role properly
• Keep the CDM and Building Regulations Principal Designer appointments clearly distinguished, even where both are held by the same organisation
• Establish practical arrangements for designers, contractors and other duty holders to cooperate and share information
• Monitor throughout the project whether the appointed duties are actually being carried out, rather than assuming that they are

That final point is one we particularly stress. An appointment made correctly at the outset can still drift if nobody checks later in the project that the Principal Designer is actively carrying out the role rather than simply holding the title.

It is also important to remember that design work often continues after construction begins. The Principal Designer appointment should therefore remain in place for as long as there is a need for the role to be performed, with continued communication between the Principal Designer and Principal Contractor.

Why This Matters

Clearer HSE guidance should be welcomed across the sector: by clients deciding whom to appoint, designers and contractors trying to understand where their obligations sit, and Principal Designers seeking to meet expectations that have not always been consistently understood.

But guidance provides a framework; it is not a substitute for professional judgement. The projects that manage design risk well are those where roles are clear from the outset, appointments are properly resourced and coordination is maintained throughout the project rather than merely documented at the beginning.

This is the space we work in at Richardson-Hill. We help clients make appropriate Principal Designer appointments, assemble pre-construction information and establish practical arrangements for managing and coordinating design risk.

If you would like support proportionate to the size, complexity and risk profile of your project, get in touch to discuss how we can help.