Contractor/Sole Trader

The BSA applies to all work your business undertakes, whether it’s a domestic re-roof, a commercial cladding project, or a High Rise Residential Building (HRRB). It introduces tougher legal responsibilities, whether you are installing the works, overseeing them, or making design decisions. 

If you act as Principal Contractor (PC) or Principal Designer (PD), you are legally responsible for coordinating building safety, including planning, managing, and monitoring works. This includes ensuring all parties are competent and that all information is properly recorded. You may not realise you are the PC or PD, so continue reading to understand when this can happen, and what you must do.

Contactors are liable to assume the role of Principal Contractor or Principal Designer for a variety of reasons, including:

• If you are the only contractor working on a job, you become the PC by default and also assume the client’s duties, dependent on whether the client is commercial or domestic and the contract terms. 
• If the homeowner does not appoint a PC or PD in writing, the contractor in control automatically assumes both roles and the client’s duties, dependent on whether the client is commercial or domestic and the contract terms. 
• If you change a manufacturer’s specification or alter the designs of an architect or architectural technician, all alterations become your responsibility, unless the changes are signed off by the PD.   
• Find more information about possible arrangements of responsibility when working with domestic clients here. 
• If you are still struggling to figure out whether you are the Principal Contractor, visit this HSE page, and read PAS 8672:2022 which defines competence requirements for Principal Contractors including roles, responsibilities, skills & higher-risk building competences. 
• If you are still struggling to figure out whether you are the Principal Designer, visit this HSE page, and read PAS 8671:2022 which addresses competence thresholds that individuals should meet when managing the duty holder functions of the PD role. 

• These roles carry enhanced responsibilities under the BSA. If you become a PC or PD, you must ensure safe design and construction practices, manage change control, and, if working on HRRBs, coordinate the “golden thread” of information.
• PCs must also be aware of their legal and contractual requirements in relation to their discharge of duties, read on for more information.

Planning and organising production: Have the competence to select competent contractors and suppliers, and ensure that all materials, products, and building systems are of suitable quality. 

Managing construction and production: Coordinate and monitor all contractors, suppliers and service providers. This includes:

• Identifying, assessing, inspecting, and testing safety-critical materials, components and systems. 
• Making sure that time or budget pressures never compromise building safety or quality. 
• Managing risks to everyone affected by the work, including the public, and maintaining control measures throughout construction. 
• Preventing unauthorised access to the site. 

Leadership and decision making: Lead projects using sound judgement, experience, and knowledge of standards and best practice. This includes managing change effectively, making informed decisions, and empowering others to take responsibility where appropriate. 

Liaising and communication: Build open and trustworthy relationships with the Client, Principal Designer, and Regulator. They should also: 

• Work closely with the Client and Principal Designer throughout the project to ensure risks are identified and managed. 
• Share relevant information to support the planning, management, and coordination of all project phases. 

Developing people and managing competence: Define the competencies needed on the project and ensure that everyone involved has the right skills, knowledge, experience, and behaviours. 

• A competence management system must be in place to assess, monitor, and record these requirements. 
• Competence should be regularly checked and revalidated to maintain safety and compliance. 

Managing quality: Keep accurate and reliable records, ideally through digital systems that support effective building information management. 

Health, safety and welfare:  

• Prepare a written Construction Phase Plan before work begins, implement it, and review it regularly to ensure it remains suitable. 
• Consult regularly with workers about health, safety, and welfare matters. 
• Ensure all workers receive a site-specific induction. 
• Provide and maintain suitable welfare facilities throughout construction. 
• Only appoint individuals or organisations with the proven competence and capability to work safely. 

Find more details about PC duties from the HSE here.  

The Principal Designer must plan, manage, and monitor the pre-construction phase of a project. They must coordinate all matters relating to health and safety to ensure, as far as is reasonably practicable, that construction projects are designed and managed without risks to anyone who builds, uses, or maintains the building. Under the Building Regulations, the Principal Designer must plan, manage, and monitor all design work during the design phase. They must coordinate design activities so that, if the building work is carried out in line with the design, it will comply with all relevant requirements of the Building Regulations. These requirements include those set out in Schedule 1, from Part A – Structure through to Part S – Infrastructure for the Charging of Electric Vehicles, and Regulation 7, which covers materials and workmanship. Materials must always be suitable for their intended use and capable of performing their required function.  

The Principal Designer must: 

• Plan, manage, monitor and coordinate health and safety during the pre-construction phase. 
• Take into account relevant information, such as existing health and safety files, that could affect design work before or after construction begins. 
• Assist the client in gathering pre-construction information and provide the necessary details to other designers and contractors so they can carry out their duties safely and effectively. 
• Work with all designers to identify and eliminate foreseeable health and safety risks where possible and reduce or control any remaining risks. 
• Ensure effective communication and cooperation between everyone involved in the pre-construction phase, coordinating their work where needed. 
• Liaise with the Principal Contractor to share information about any design-related risks that must be managed during construction.

Find more details about PD duties from the HSE here. 

This NFRC Guidance Note explains responsibilities contractors may undertake in relation to the design of the works prior to signing contracts and how to avoid taking on unnecessary risk.

• You must demonstrate organisational competence, aligned with BS 8670. This includes having the right structures, systems, and people in place to manage safety and risk.  
• BS 8670 can be purchased from BSI here.
• NFRC Guidance Note 73: Organisational and Individual Competence can be viewed for free by NFRC Members here. 

SKEB stands for Skills, Knowledge, Experience, and Behaviours. As a leader or business owner, you must ensure that everyone you hire or manage is competent for the tasks they undertake and keep records to prove it. The exception to this is those you are training to be competent, whose work must be adequately supervised. 

Demonstrating competence should not be an issue for most businesses, so long as they are keeping a record of what they have done in the past and why they are qualified to do a job in the future. This can include, but is not limited to: 

• Employees with valid CSCS or equivalent cards 
• Up-to-date certificates for any systems or products you install where appropriate 
• Training or CPD (continuing professional development) as appropriate 
• Professional qualifications (appropriate NVQs) 
• A portfolio of evidence (previous works completed 
• Job description 
• Testimonials from previous clients 

• The definition of an HRB differs across the devolved nations. Ensure you understand the differences so that you are aware when you are working on an HRB. 
• England HRBs: At least 18m in height or has at least 7 storeys and contains at least 2 residential units. A ‘residential unit’ is defined as a ‘dwelling’ or any other ‘unit of living accommodation’ and so has wide meaning. More information here.  
• Welsh HRBs: Buildings at least 18 meters tall or with seven storeys. They must also contain at least one residential unit, a hospital with overnight stays, a care home, or a children’s home. This is a notable contrast to England’s requirement of two or more residential units. Welsh regulations explicitly include children’s homes as HRBs, whereas in England, such facilities fall under broader categories like student accommodation if they meet specific thresholds. More information here. 

• For HRBs in England, your work will be subject to a three-step approval system: planning (Gateway 1), technical design (Gateway 2), and completion (Gateway 3). You cannot proceed to the next stage without approval. 
• Wales is currently in the process of implementing its own landmark Building Safety (Wales) Bill, and we will keep you updated on developments.  
• In light of heavy delays at Gateway 2, the Construction Leadership Council (CLC) in partnership with the BSR has published a suite of guidance documents to support successful applications. Read the guidance here. 
• They have also released guidance for Gateway 3 applications, which can be found here. 

When working on an HRB, you will need to supply competence evidence, safety case documents, and design/product details. Accurate and traceable records are essential. 

• The Building Safety Regulator (BSR) oversees HRBs. If you work on one, you may be subject to inspections or enforcement. Cooperation and compliance are essential. Read NFRC’s guidance note on the Building Safety Regulator here for more information.  
• In June 2025, the Building Safety Regulator was moved from under the Health and Safety Executive to the Ministry of Housing, Communities and Local Government. 

A Commercial Client is anyone (individual, partnership or organisation) who has construction work carried out for them that is done in connection with a business, whether the business operates for profit or not. Commercial clients include local authorities, housing associations or other landlords who own domestic properties.

For commercial clients (businesses, housing associations, developers), legal duties are stricter. Commercial clients must actively: 

• Appoint competent dutyholders 
• Ensure safe design and planning 
• Monitor compliance during the works 
• Ensure that those they hire to complete the works are competent in: Designing the works, Planning the works, Managing the works, Supervising the works, and Undertaking the actual works

A Domestic Client is someone who has construction work carried out for them that is not done in connection with a business (usually on their own home or the home of a family member). 

Under the BSA, domestic clients have reduced duties. The law recognises that domestic clients (e.g. homeowners) may not fully understand or manage their legal duties. If a domestic client does not appoint a Principal Contractor or Designer, those responsibilities automatically fall to: 

• The contractor, if only one is involved 
• The Principal Contractor, if more than one 

Other possible arrangements of responsibility may arise when working with a domestic client:

• If a domestic client provides a roof specification to a roofing contractor as to what they want installed, then the client is the Principal Designer and as such should be able to prove their competence to undertake this role. 
• If a domestic client is undertaking the roofing works themselves, then it is the domestic client’s responsibility to comply with all the relevant building regulations. 
• If a designer is undertaking design works for a domestic client and they are aware that the domestic client is going to undertake the works themselves then they have a duty to satisfy themselves that the client is aware of their responsibilities to comply with all relevant building regulations and has the competence to complete the works. Matters regarding a lack of competence could now be considered as a contravention of the building regulations and may lead to Initial Notice cancellation and enforcement action. 

Read NFRC’s guidance note ‘Understanding the BSA and Building Regulations for Domestic Work’ here.  

If you are a contractor dealing directly with the client or building owner, you should, where possible, verify that the client: 

• Has formally appointed a Principal Designer and Principal Contractor (in writing)
• Has sufficient time and resources allocated for the safe execution of the work 
• Is aware of and fulfils their duties (especially on HRBs or complex jobs) 

If these steps aren’t taken, the default duty holder provisions may apply, meaning that you (as contractor) could inherit those legal responsibilities by default, depending on contract terminology. It’s in your interest to ensure clients are compliant before you start work and be clear on your responsibilities. 

• Read NFRC’s guidance note on Part 2A of the Building Regulations 2010 here to understand more about regulations regarding “Dutyholders and Competence”, focusing on accountability and ensuring that all clients, designers and contractors involved in building work have the required competence and behaviours. 

If you are directly liaising with the client or building owner, you should advise clients on the practical implications of their duties, such as the need for competent appointments and good recordkeeping. 

However, be careful not to:  

• Assume responsibility for design unless formally appointed. 
• Offer advice outside of your competence (e.g. structural safety, fire engineering). 
• Accept vague or verbal instructions on key roles or design decisions. Any change or alteration within the design should be recorded with records kept. 

Clearly define your scope of work in contracts and proposals, especially regarding compliance and product substitution. If a client asks you to make a change or take on a role outside your remit, you must flag it formally and in writing and get sign off from the Principal Designer so that they ultimately have design responsibility. 

If you are subcontracting to a contractor or main contractor, ensure you have read and understood your contract terms and conditions as they relate to your responsibilities under the BSA.   

Under the HASAWA 1974 you do have a legal responsibility for safety of your operatives and others within the vicinity of your works, regardless of your position within the supply chain. 

The golden thread of information is currently mandated for HRBs, but application of Golden Thread principles is expected to extend to other building types in the future as the building safety regime evolves. 

The “Golden Thread” refers to the structured digital record of building information that must be kept accurate, up-to-date, and accessible throughout the building lifecycle. For contractors, this means documenting and sharing: 

• Design decisions (including changes and justifications) 
• Product selections (with manufacturer specs and certificates) 
• Inspection and test results 
• Installation evidence (e.g. photos, certificates) 
• Site-specific risk and safety data 

Records should be stored in an accessible digital format and tagged clearly to allow others (such as the Principal Designer or Accountable Person) to retrieve them when required.  

More Golden Thread guidance from the Building Safety Regulator can be found here.  

CLC guidance on Golden Thread requirements for HRBs can be found here.  

• Information relevant to building safety must be retained for at least 15 years. For Higher-Risk Buildings (HRBs), the Building Safety Regulator may require up to 30 years of records in some instances.
• More HSE advice on storing your building’s information can be found here.

For HRBs, the Accountable Person (AP) or Principal Accountable Person (PAP) or Principal Accountable Person (PAP) is responsible for managing building safety during occupation. However, contractors must actively cooperate with them by: 

• Providing timely, accurate records during construction and handover 
• Responding to information requests from the AP/PAP or Regulator 
• Reporting any potential building safety risks or non-compliance 

Responsibilities to share information and cooperate carry on even after work is completed. 

Non-compliance with the BSA can carry serious consequences such as stop notices, compliance notices, or prosecution:

• Non-compliance notices are now more severe 
• Insurance considerations are now more extensive  
• Fines are now unlimited whereas they were a maximum of £5,000 under the CDM  
• The Building Safety Regulator has powers to inspect your work, demand corrective action, and refer non-compliant parties for enforcement. You may also be sued by clients or leaseholders under extended defect liability periods (15 years for new work, 30 years for existing issues) 

Contractors must:

• Work with demonstratable appropriate competence 
• Share safety-critical data 
• Ensure changes are authorised  
• Follow gateway and recordkeeping requirements 

Company directors and senior managers are no longer shielded from liability. If your business fails to comply, you could be held personally accountable under Section 161 of the Building Safety Act and broader criminal law.