What is a Building Safety Act Principal Designer?
Part of our Consultant series
The BSA (Building Safety Act) Principal Designer is the person legally responsible for making sure that a building’s design meets the Building Regulations. They plan, manage and check the design work so that every element of the building, from its structure to its insulation and fire safety, performs safely and as intended. In simple terms, they make sure that what is drawn can be built safely and legally.
This role was created by the Building Safety Act 2022, a law introduced to make the construction industry safer, clearer and more accountable. It was written in direct response to the Grenfell Tower fire in 2017, which exposed the absence of a single point of responsibility for the safety of the building. The new Principal Designer role was introduced to fix that problem by ensuring that a qualified professional is in charge of compliance from the earliest design stages.
Why the Building Safety Act 2022 was introduced
The Grenfell Tower fire was a national tragedy that revealed deep failures in how buildings were designed and managed. The inquiry found widespread confusion about who was responsible for safety. Documentation was incomplete, product testing was inadequate, and design changes were made without understanding their consequences.
At its core, the problem was that no one was clearly accountable. Each party believed that someone else was checking compliance. The Building Safety Act 2022 was created to end that lack of clarity by defining exactly who is responsible for safety and compliance at each stage of a project.
The Act introduced three key dutyholder roles that apply to nearly every project requiring Building Regulations approval: the Client, the Principal Designer, and the Principal Contractor. Together they must plan, manage and monitor the design and construction work to ensure compliance.
The late inclusion of domestic projects
When the Building Safety Act was first drafted, it was intended to cover only high-risk residential buildings such as towers and large multi-unit schemes. Smaller domestic projects were originally expected to be excluded. However, at the final stage before publication in Autumn 2023, the government changed its position and brought domestic projects within the scope of the law.
This means that even modest residential projects now require formal appointments for both a BSA Principal Designer and a BSA Principal Contractor. Home extensions, loft conversions and house refurbishments must all follow the same legal process as larger developments.
For homeowners, this change provides reassurance that someone is formally responsible for checking that their project meets safety and compliance standards. It also ensures that the design process is properly documented and reviewed before any construction begins.
What the BSA Principal Designer does
The BSA Principal Designer oversees design compliance. They coordinate all the consultants and designers on a project, ensuring that the entire design satisfies Building Regulations. They must identify potential issues early, resolve them, and maintain clear records to demonstrate how compliance has been achieved.
Their responsibilities include:
Planning and managing the design process so that Building Regulations are considered at every stage.
Checking that each designer understands how their work fits into the overall design.
Making sure that design changes do not undermine compliance.
Coordinating and sharing technical information among the design team.
Confirming that everyone appointed is competent for their role.
Preparing and maintaining documentation for Building Control submission.
The Principal Designer acts as the central point of accountability for design compliance, ensuring that all parts of the design work together safely and lawfully.
The volume of paperwork and record keeping
One of the major changes introduced by the Building Safety Act is the requirement for extensive documentation. The Principal Designer must be able to prove, through a clear paper trail, that their role has been properly undertaken. This involves keeping detailed records of design decisions, consultant correspondence, design changes, and evidence of compliance for every element of the building.
This paperwork provides Building Control and the Building Safety Regulator with the evidence they need to verify that the project has been managed competently and that the final design meets all regulatory standards. It also creates a permanent record that can be referred to later if any questions arise about safety or performance.
For architects and engineers, this means that the role of Principal Designer is not only about managing the design process but also about documenting it rigorously. The paperwork is not optional; it is a legal requirement that demonstrates due diligence and professional accountability.
How the BSA Principal Designer differs from the CDM Principal Designer
Many clients are familiar with the Principal Designer under the Construction, Design and Management Regulations 2015, often referred to as CDM. That role focuses on managing health and safety risks during the design and construction stages to protect those who build, use and maintain the structure.
The BSA Principal Designer’s responsibilities are different. Their focus is on compliance with Building Regulations rather than construction safety. They ensure that the completed building itself will meet all required performance standards for structure, fire safety, energy efficiency and accessibility.
In some cases, particularly on smaller projects, the same professional may act as both the CDM and BSA Principal Designer, but it is important to understand that the two roles have different legal duties and reporting requirements.
Who can act as a BSA Principal Designer
The Building Safety Act restricts this statutory role to certain qualified professionals who already have recognised competence and accountability through their professional bodies. These are:
Architects
Building surveyors
Structural or civil engineers
These professionals are considered competent because they combine technical expertise with a regulated code of conduct, professional indemnity insurance and a requirement to maintain continuing professional development. This combination provides both the knowledge and the accountability needed to manage design compliance.
While other consultants can assist with design or technical coordination, they cannot hold the title of BSA Principal Designer unless they are a member of one of these professional groups.
The growing role of the BSA Advisor
The duties of the BSA Principal Designer come with a substantial amount of administrative work. The need for continuous documentation, version control and formal evidence of compliance has led to the creation of a new supporting role known as the BSA Advisor.
A BSA Advisor cannot act as the statutory dutyholder but can assist in preparing, maintaining and organising the records needed to demonstrate compliance. They may help by producing compliance schedules, tracking consultant competence, collecting certificates and statements, and collating the information required for Building Control submissions.
This collaboration allows the Principal Designer to focus on the technical and design management aspects while ensuring that the administrative requirements are fully met. The use of a BSA Advisor is increasingly common on residential projects, where architects often already carry several responsibilities such as contract administration and project management.
The relationship with Building Control and the Principal Contractor
The BSA Principal Designer works closely with Building Control throughout the design stage. They must provide evidence that the design, once built, will comply with Building Regulations. If design changes occur during construction, they must review and confirm that those changes remain compliant.
The Principal Contractor then carries responsibility through the construction stage. Together, the Principal Designer and Principal Contractor form a continuous chain of accountability from concept design to completion. Each must keep comprehensive records, and both can be held legally responsible for compliance failures. Although it is the architect who would be criminally responsible.
What this means for domestic clients
For domestic clients, the introduction of the Building Safety Act formalises much of what a good architect already does. When an architect leads a project, coordinates consultants and manages Building Regulations submissions, they are already ensuring compliance. The Act now gives this responsibility a legal title and structure.
Clients will now see in their appointment documents that the architect or engineer has been appointed as the BSA Principal Designer. They will also need to appoint a Principal Contractor before building work begins.
Even for smaller projects, the paperwork involved can be extensive. Working with a BSA Advisor helps manage this efficiently, ensuring that every stage of the process is properly recorded and ready for submission.
The wider impact of the Building Safety Act
The Building Safety Act represents a shift in culture for the construction industry. It moves away from a fragmented approach to one based on traceability, competence and accountability. By naming responsible professionals, it provides greater confidence for clients, regulators and the public that buildings are being designed and constructed safely.
For architects, engineers and surveyors, it reinforces the importance of professional judgement, coordination and record keeping. It also acknowledges that good design is not only about appearance or function but about compliance and public safety.
Although the new processes require more paperwork, the long-term benefits are clear. Projects that are well documented are easier to manage, easier to inspect and less likely to face problems later.
In summary
The BSA Principal Designer is a qualified professional responsible for managing and proving design compliance under the Building Safety Act 2022. The role was created in response to the Grenfell Tower fire to ensure that every building has a clearly identified person accountable for its safety and regulatory compliance.
Only architects, chartered engineers and chartered building surveyors can act in this capacity. They are supported by BSA Advisors who help handle the extensive paperwork and record keeping required to demonstrate that the role has been properly undertaken.
For clients, the new system provides reassurance that the design of their building has been managed with the care, competence and documentation that safety now demands.