Has the industry misread the principal designer?

Few roles have attracted as much scrutiny in recent years as the principal designer (PD). CDM 2015 placed the PD at the heart of managing health and safety through design, arriving with considerable anticipation when the regulations came into force on 6 April 2015.

Nearly 10 years on, the Building Safety Act 2022 has introduced the building regulations principal designer (BR PD), adding a new dimension to a role many believed they already understood.

For practitioners reading this, the distinctions between the two regimes are well-rehearsed. It is not necessarily design professionals who are confused, but rather their clients – many of whom are still unclear why the industry now speaks of two principal designers, let alone why two appointments or fees may be required. The result is a growing expectation that one role may simply “cover” the other.

For a profession that has spent years refining the application of CDM, the arrival of a second PD should have been the moment where competence frameworks converged. Instead, a quieter and more uncomfortable question has emerged. Do we understand what the law expects of each regime, and have we been too quick to assume alignment where none was intended? And more practically: how do PDs convey this distinction to clients?

The new BR PD has invited comparison with the CDM PD. Both roles coordinate, both influence design and both intervene in the pre-construction period. It is therefore unsurprising that the industry assumed the two roles may be synonymous. This assumption has now translated into procurement behaviours: clients pushing for single appointments, blended scopes or value engineering of what they perceive to be duplicated effort.

There is often an assumption that existing design managers can carry out the role of BR PD; legislation doesn’t deny that. In the same way, a CDM PD can take on the role of the BR PD where the building regulations allow it.

The key question is not whether they may be appointed, but whether their competence and organisational capability are sufficient to discharge the duties in practice. The difficulty many PDs now face is articulating that competence gap in a way that resonates commercially as much as technically.

CDM looks at the full building lifecycle, from design and construction through to use and eventual demolition. The BR PD role sits in a technical regulatory context that demands interpretive capability. Yet the building regulations element is often overlooked or reduced to documentation, rather than understood as the central purpose of the role. Assessing compliance with building regulations is not a clerical task. It is analytical and at times adversarial. PAS 8671 makes this clear.

The BR PD must understand the technical framework well enough to challenge assumptions, assess non-prescriptive approaches and form defensible views on compliance.

These are not minor distinctions. They explain why so few sectors outside building control and specialist advisory practice have produced credible BR PD capability at pace. They also explain why experienced CDM and design professionals, for all their value, rarely arrive with full building regulations competence pre-assembled. The issue for PDs is not just possessing this competence, but convincing clients that it is materially different from what they already pay for.

The Building Safety Act has pulled behavioural competence into sharper relief than CDM ever did. Accountability, ethics and the duty of care are not abstract qualities in the post-Grenfell regulatory environment. They are central to how regulators, inquiry outcomes and future case law will interpret the role of the BR PD. Technical knowledge will always matter. But it will not be enough on its own.

Although CDM and building safety share a family resemblance in competence frameworks, neither regime intends competence to be static or universal. It remains variable and context-dependent for both PD roles.

Both roles are significant in scope, but their responsibilities diverge. CDM draws from a wide range of health, safety and welfare legislation, including the Workplace and Work at Height Regulations, to name a few. These duties inform preconstruction information, construction phase plans, the health and safety file, and most importantly design risk management.

By contrast, BR PDs must understand the procedures for higher risk buildings (HRBs), coordinate gateway submissions, and contribute to the long-term golden thread. 

Industry frustration often arises when BR teams repurpose CDM documentation into building regulations contexts. Construction phase plans reappear as construction control plans. Other issues like compliance statements re-surface in fire and emergency files without a connection to actual and specific building safety risks. These adaptations are understandable, but they are not aligned with the legislative purpose.

Clarifying legal intent helps. Asking why a document exists and what outcome it serves encourages practitioners to align their work with the spirit of the law rather than habit or precedent. For many PDs, the challenge is explaining to clients that “repurposed” documentation does not meet the regulatory test, however familiar it looks.

If the industry has misread the PD, it is because the title has been mistaken for equivalence and convenience mistaken for competence. Both regimes demand different expertise of the role. Answering both requires active judgement, not assumption. And until clients fully appreciate that distinction, PDs will continue to face the uncomfortable task of advocating for the value, cost and necessity of dual appointments.