Principal Designer Duties Explained
The Principal Designer is a key health and safety role on most construction projects. Here is what the duties are under CDM 2015, when one is needed, and how the role is often misunderstood.
Under the Construction (Design and Management) Regulations 2015 (CDM 2015), the Principal Designer is the designer appointed by the client to plan, manage and coordinate health and safety during the pre-construction phase of a project. Their core duty is to identify, eliminate or control foreseeable health and safety risks through the design, coordinate the work of other designers, and provide the right information to those who need it, including the Principal Contractor. A Principal Designer is required whenever a project involves more than one contractor. It is a separate role from the Building Regulations Principal Designer, which sits under different legislation.
What CDM 2015 is, in brief
CDM 2015 is the main set of health and safety regulations for construction projects in Great Britain. It allocates duties to a set of dutyholders, including the client, designers, the Principal Designer, contractors and the Principal Contractor. The aim is simple: to make sure health and safety is considered and managed throughout a project, from the earliest design decisions through to construction and beyond, so that risks are designed out wherever reasonably practicable rather than left for site to deal with.
When is a Principal Designer required?
The client must appoint a Principal Designer, in writing, whenever a project involves, or is likely to involve, more than one contractor. This is the case on most projects, even modest domestic ones where, say, a builder and a separate electrician are involved. If genuinely only one contractor is engaged, the specific Principal Designer role does not apply, but the underlying designer and client duties under CDM 2015 still do, and someone must still manage health and safety. On domestic projects, where the client is a homeowner rather than a business, certain client duties pass to the designer or contractor by default.
The core duties of a Principal Designer
The Principal Designer's responsibilities focus on the pre-construction phase, the period of design and planning before and during construction. They include:
- Planning, managing and monitoring the pre-construction phase
- Identifying, eliminating or controlling foreseeable risks through design
- Coordinating health and safety between all the designers
- Ensuring designers cooperate and apply the general principles of prevention
- Preparing and providing relevant pre-construction information
- Liaising with the Principal Contractor and sharing information for the construction phase plan
- Preparing the health and safety file where required
The emphasis is on managing risk at the design stage, where it can be most effectively addressed. This dovetails naturally with structural design: decisions about how loads are carried, sequencing, temporary works and buildability all carry health and safety implications that are best resolved on the drawing board.
How it differs from the Building Regulations dutyholder role
This is a common source of confusion. Since changes following the Building Safety Act, there is also a Building Regulations Principal Designer, a separate dutyholder role concerned with managing and coordinating compliance with the Building Regulations during design. Despite sharing a name, it is not the same as the CDM 2015 Principal Designer:
- The CDM Principal Designer manages construction health and safety in the pre-construction phase.
- The Building Regulations Principal Designer manages Building Regulations compliance during design.
They arise under different legislation and have different duties. The same organisation can sometimes hold both roles, but they should never be assumed to be one and the same. If your project also needs compliance support, our guide to structural calculations for Building Regulations explains the design-compliance side.
Who can be a Principal Designer?
The Principal Designer must be a designer (an organisation or individual whose work involves design) with the skills, knowledge, experience and, where an organisation, the organisational capability to carry out the role. As a structural engineering consultancy, EMA can take on or support the Principal Designer function on appropriate projects, applying engineering judgement to design risk management as part of our wider construction support service.
The bottom line for clients
If your project involves more than one contractor, you have a legal duty to appoint a Principal Designer in writing. Doing so early, before significant design work, lets risk be managed when it matters most. To discuss whether your project needs one and how we can help, see our Principal Designer services.
Principal Designer questions
What is a Principal Designer under CDM 2015?
Under the Construction (Design and Management) Regulations 2015, the Principal Designer is the designer appointed by the client to plan, manage and coordinate health and safety during the pre-construction phase of a project. The role is required when a project involves more than one contractor.
When do I need to appoint a Principal Designer?
A Principal Designer must be appointed in writing by the client whenever a construction project involves, or is likely to involve, more than one contractor. If only one contractor is involved, the Principal Designer role does not apply, but designer and client duties under CDM 2015 still do.
Is the CDM Principal Designer the same as the Building Regulations Principal Designer?
No. They are separate dutyholder roles under separate legislation. The CDM 2015 Principal Designer manages construction health and safety, while the Building Regulations Principal Designer role concerns compliance with the Building Regulations. The same organisation may sometimes hold both, but the duties are distinct.
Need a Principal Designer for your project?
Tell us about your project and who is involved, and we will advise whether a Principal Designer is required and how we can support the role.