If you are planning a construction project, whether a home extension, new build, or small development, you may come across the term Principal Designer and wonder when the role applies and who is responsible for appointing them.
This article explains when a Principal Designer must be appointed, what the role involves, and how it applies to residential projects.
What Is a Principal Designer?
The Principal Designer (PD) is a statutory role introduced under the Construction (Design and Management) Regulations 2015 (CDM 2015).
The purpose of the role is to ensure that health and safety risks are considered and managed during the design stage, before construction begins.
The Principal Designer is responsible for:
- Planning, managing, and monitoring health and safety during the design phase
- Identifying and reducing foreseeable risks arising from design decisions
- Coordinating designers and consultants
- Preparing and managing pre-construction information
In simple terms, the role exists to design out risk wherever possible.
When Is a Principal Designer Required?
A Principal Designer must be appointed where there is, or it is reasonably foreseeable that there will be, more than one contractor involved in the project.
This includes most projects where:
- An architect or designer is appointed, and
- A builder or contractor will carry out the works
As a result, the majority of residential projects require a Principal Designer, even where the works are relatively small.
Who Is Responsible for Appointing the Principal Designer?
The Client is legally responsible for appointing the Principal Designer.
On residential projects, the Client is typically the homeowner or landowner. However, many Clients are not familiar with CDM regulations, which is why the appointment is often managed as part of the architectural service.
If a Principal Designer is not formally appointed, the Client may retain the legal duties by default, which can expose them to unnecessary risk.
When Should the Principal Designer Be Appointed?
The Principal Designer should be appointed as early as possible, ideally:
- At the start of the design process
- Before planning or technical design progresses too far
Early appointment ensures that health and safety considerations are integrated into the design from the outset, rather than addressed retrospectively.
Who Can Act as Principal Designer?
The Principal Designer must be a designer with sufficient skills, knowledge, and experience to manage design-stage health and safety.
On residential projects, this is commonly:
- The architect or lead designer, or
- In some cases, the principal contractor, if appointed early and competent
Architects are often best placed to fulfil the role, as they are already coordinating the design and consultant team.
What About Building Regulations?
It is important to note that the Principal Designer under CDM 2015 is a separate role from the Principal Designer under the Building Regulations introduced by the Building Safety Act 2022.
On many residential projects:
- The CDM Principal Designer manages health and safety in design, and
- The Building Regulations Principal Designer coordinates design compliance with the Building Regulations during technical design
These roles must be clearly identified to avoid gaps or confusion.
What Happens If a Principal Designer Is Not Appointed?
If no Principal Designer is formally appointed:
- The Client may automatically assume the duties
- Health and safety coordination can be unclear
- There is an increased risk of non-compliance
Clear appointment protects both the Client and the project team.
Key Points to Remember
- Most construction projects require a Principal Designer
- The role applies to residential projects, not just commercial sites
- The Client is responsible for making the appointment
- Early appointment reduces risk and improves project outcomes
- CDM and Building Regulations Principal Designer roles are distinct
How We Manage This at Connor Ferris Architects
At Connor Ferris Architects, we act as Principal Designer as part of our service unless you choose to appoint an alternative. This ensures:
- Clear responsibility
- Early risk management
- Compliance with statutory duties
- A smoother transition into construction
If you prefer to appoint someone else, this can be done provided it is confirmed in writing and responsibilities are clearly coordinated.
