The landscape of construction in England has changed significantly in recent years. Following the tragic events at Grenfell Tower, the introduction of the Building Safety Act 2022 (BSA) fundamentally rewrote the rulebook on how we design, construct, and manage buildings, particularly Higher-Risk Buildings (HRBs). At the very heart of this legislative overhaul is a concept coined by Dame Judith Hackitt: the “Golden Thread” of information.
This guide explains The Golden Thread for UK Building Projects: What Drawings and Digital Records Must Be Kept, outlining the practical steps, drawings, and digital records needed for compliant information management across a project’s lifecycle.
But what exactly does this mean for architects, engineers, contractors, and building owners in practical terms? Gone are the days of handing over disorganised boxes of paper manuals and roughly marked-up drawings at practical completion. Today, the law requires clear, accurate and usable digital records for higher risk buildings in England.
In this comprehensive guide, we will explore the exact building safety act drawings and digital records that must be retained. We will look at the nuances of the gateway system, the specific responsibilities of dutyholders, and how modern digital tools are making compliance more achievable than ever.
Before diving into the specific drawings and data required, it is crucial to understand the philosophy behind the Golden Thread.
The Golden Thread is both the information that allows you to understand a building and the steps needed to keep both the building and people safe, now and in the future. It ensures that the right people have the right information at the right time. Crucially, the BSA dictates that this information must be stored digitally, be highly secure, and present a single source of truth.
For higher risk buildings in England, the golden thread is not a recommendation; it is a legal requirement. A higher risk building is generally a building that is at least 18 metres high or has at least seven storeys, and either contains at least two residential units or is a hospital or care home. The Building Safety Regulator (BSR), part of the Health and Safety Executive (HSE), oversees building control for higher risk buildings. Work must not start without the required approval, and BSR can reject applications where the information does not show sufficient compliance.
Meeting the digital golden thread requirements means abandoning siloed working and embracing an environment where information flows seamlessly from the initial concept, through the rigorous design and construction gateways, and directly into the hands of the individuals managing the building safely in occupation.
Historically, architectural and engineering drawings were fluid documents. They evolved rapidly on-site, often with design issues resolved on the fly by contractors, resulting in a finished building that bore only a passing resemblance to the original planning submissions. Under the BSA, this approach is entirely obsolete.
The building safety act drawings form the visual backbone of the Golden Thread. These documents must precisely represent the building as it is actually built, not just as it was conceptualised.
To maintain a robust Golden Thread, practices must transition completely to golden thread CAD drawings and digital models. The legislation requires these drawings to be:
These CAD drawings are not just architectural floor plans. They encompass structural engineering details, mechanical, electrical, and plumbing (MEP) layouts, and intricate fire safety schematics. Every line drawn must be accountable and verifiable.
The BSA introduces a strict “hard stop” Gateway system for Higher-Risk Buildings. You cannot simply proceed to the next phase of a project without explicit approval from the Building Safety Regulator. The information you provide at these gateways forms the early stages of your Golden Thread.
Gateway One occurs at the planning application stage. It requires the submission of a Fire Statement, ensuring that fire safety considerations are embedded into the earliest stages of the design process, such as site layout, water supplies for firefighting, and access for emergency vehicles.
Gateway Two replaces the traditional building control deposit of plans stage. But what are gateway two design requirements?
In short, before construction starts, the client must obtain building control approval from BSR. The application must include enough information to show how the work will comply with building regulations and how compliance will be managed. You must submit highly detailed higher-risk building design information, demonstrating exactly how the proposed building complies with all relevant Building Regulations.
For building control approval, applicants may need to submit:
If the BSR is not satisfied with the level of detail or the proposed safety measures, construction simply cannot begin. For higher risk buildings, unresolved design decisions and site changes must be properly assessed, recorded and managed through the approved documents, the change control plan and the change control log.
Gateway Three occurs at practical completion. This is where the building as constructed is assessed against the design approved at Gateway Two. The BSR will only issue a completion certificate, allowing the building to be legally occupied, if the Golden Thread of information is complete, accurate, and ready to be handed over to the Accountable Person.
To satisfy the requirements of the Gateways and build a robust Golden Thread, several specific types of information and drawings must be meticulously created and maintained.
Fire safety is at the absolute core of the BSA. Therefore, mandatory fire strategy plans are some of the most highly scrutinised documents in the Golden Thread.
These are not standard floor plans with a few fire exit signs layered on top. High-quality fire strategy plans must visually detail:
One of the major failures identified post-Grenfell was the lack of adequate fire compartmentation and the poor installation of fire-stopping materials.
Documenting fire-stopping and compartmentation is now a critical digital record. This means your CAD drawings and BIM models must clearly denote where fire-resisting walls, floors, and ceilings are located, and precisely what their fire resistance rating is (e.g., 60 minutes, 120 minutes).
Penetrations through fire resisting compartments, such as pipes, cables and ductwork, should be identified and recorded. Good practice includes using dated photographic evidence, inspection records and product certification, linked to drawing or model locations, before works are covered up. This helps show what was installed and supports future inspection, maintenance and handover.
Alongside fire safety, structural integrity is the other primary pillar of the BSA. For an occupied high rise residential building, the Principal Accountable Person should prepare a safety case report as soon as possible. The report should show how building safety risks, including the spread of fire or smoke and structural failure, are being assessed and managed.
The foundation of this report relies heavily on structural safety case report data generated during the design and construction phases. This includes:
Having this data securely stored in the digital building record UK ensures that future structural modifications or assessments can be carried out safely, without relying on guesswork or destructive investigations.
Modern high-rise buildings are complex machines, packed with active safety technology. Life safety systems mapping is essential for both the BSR submission and the eventual facility management of the building.
Your digital records must contain comprehensive schematics and layouts for:
Crucially, the Golden Thread requires proof that these systems not only exist on the drawings but have been successfully commissioned, tested, and integrated. Cause and effect matrices—which explain, for example, exactly which vents open and which lifts ground when a specific smoke detector is triggered—must be included in the digital record.
The Building Safety Act places specific legal duties on designated individuals and organisations to ensure this digital information is curated correctly.
The BSA establishes the formal role of the Principal Designer (PD) for building regulations. This role is distinct from the CDM (Construction (Design and Management) Regulations) Principal Designer, although the same organisation can fulfil both.
The principal designer compliance duties are onerous. The PD is legally responsible for planning, managing, and monitoring the design work to ensure it complies with Building Regulations. Crucially, they are the custodians of the Golden Thread during the design phase.
They must ensure that all designers (architects, structural engineers, MEP consultants) are coordinating their work. If the structural engineer moves a column, the PD must ensure the architect’s fire strategy plan and the MEP engineer’s ductwork layout are updated to reflect this change. The PD must guarantee that the higher-risk building design information submitted at Gateway Two is cohesive, fully compliant, and free of clashes.
No matter how rigorous the Gateway Two design is, changes during construction are inevitable. Supply chain issues might dictate a change in cladding material, or an unexpected underground service might force a foundation redesign.
Under the BSA, managing architectural changes during construction requires a formal, heavily documented Change Control process. You can no longer make ad-hoc changes on-site.
Changes are generally categorised into ‘notifiable’ and ‘major’ changes:
Every change, no matter how small, must be logged, justified, assessed for its impact on fire and structural safety, and immediately reflected in the digital building safety act drawings. This change log forms a vital part of the Golden Thread, providing an audit trail of exactly how and why the “as-built” building differs from the Gateway Two design.
Managing this vast amount of data, drawings, and compliance logs is impossible using traditional analogue methods. The industry is relying heavily on sophisticated software to meet the legislative demands.
Building Information Modelling (BIM) can be an effective way to manage golden thread information, but compliance depends on the quality, accuracy, accessibility and management of the information, not simply on using a BIM model. Using BIM for building safety act compliance allows project teams to create a data-rich 3D digital twin of the building before it is constructed physically.
Within a BIM environment, a 3D door is not just a rectangle drawn on a screen; it is a digital object containing metadata about its fire rating, its manufacturer, its acoustic properties, and its maintenance schedule.
Utilising golden thread BIM information UK standards (often aligned with the UK BIM Framework and ISO 19650) ensures that data is structured, classified, and easily transferable. It allows the Principal Designer to run automated clash detection, ensuring a steel beam doesn’t intersect a crucial fire extraction duct, before the design is submitted to the BSR.
While 3D BIM is the gold standard for complex HRBs, not every aspect of the Golden Thread relies solely on heavy 3D models. Fast, accurate, and highly compatible 2D and 3D drafting tools remain the workhorses of the construction industry.
Software like BricsCAD is relevant in this space because Octave describes BricsCAD BIM as a DWG based CAD platform with BIM capabilities. Used within a properly managed record keeping system, it can help teams produce, update and share accurate CAD and BIM information. However, golden thread compliance still depends on project processes, version control, competent review and the completeness of the information supplied.
Furthermore, modern CAD platforms offer seamless integration with larger Common Data Environments (CDEs) and BIM workflows, allowing 2D details (such as intricate fire-stopping cross-sections) to be linked directly to the overarching 3D model. Whether drafting mandatory fire strategy plans or refining structural details, using professional, stable CAD software is non-negotiable for BSA compliance.
As construction draws to a close, the focus shifts to Gateway Three and the process of handing the building over to the client. This is historically where information was lost, degraded, or ignored. The BSA is intended to reduce the risk of information being lost, degraded or ignored at handover.
The building safety handover is a formal, highly regulated event. To pass Gateway Three, the Principal Contractor and Principal Designer must sign declarations stating that the building has been constructed in accordance with the approved Gateway Two designs (including any approved changes) and complies with Building Regulations.
The building safety regulator submission standards dictate that the Golden Thread must be handed over in a digital format that is immediately usable by the Accountable Person. The BSR will scrutinise this information to ensure it accurately reflects the finished structure. If the information is incomplete, poorly formatted, or inaccurate, the BSR will refuse to issue the completion certificate. Without this certificate, it is a criminal offence to allow residents to move into the building.
A critical component of this handover phase is regulation 38 fire safety information transfer. Regulation 38 of the Building Regulations strictly mandates that fire safety information must be handed over to the ‘responsible person’ at the completion of a project, or when a building is first occupied.
Under the BSA, the enforcement of Regulation 38 has been significantly tightened. Regulation 38 fire safety information should not be treated as a generic close out pack. The transfer must include all mandatory fire strategy plans, active and passive fire protection specifications, commissioning certificates, and cause-and-effect data. This ensures the people operating the building have the exact information they need to conduct immediate fire risk assessments and maintain the life safety systems mapping safely.
The term “as-built” has historically been treated loosely in construction, often just meaning “as-designed, with a few red pen marks.”
Today, as-built records for residential blocks must be literal. If a pipe was moved 500mm to the left on-site to avoid a structural beam, the digital drawings must show that pipe 500mm to the left.
These true as-built records encompass:
The Golden Thread does not stop when the building is handed over. In fact, one could argue that its true value is only realised during the operational phase of the building, which can last for many decades.
Once the Accountable Person takes control of the building, they are legally responsible for keeping the Golden Thread alive and up to date. But how to maintain a digital building manual effectively?
Firstly, the manual must reside in a secure, backed-up digital environment—often a cloud-based Common Data Environment or a dedicated Facilities Management (FM) platform.
Whenever maintenance is carried out, or minor refurbishments occur, this manual must be updated. For example, if a fire door is replaced due to damage, the digital record must be updated to show the new door’s specification, its fire rating certification, the date of installation, and the details of the competent person who installed it.
The ongoing management of the digital building record UK requires a shift in culture for property managers and landlords. The information must be made available to various stakeholders, including:
For existing buildings that were completed before the BSA came into full force, there is still a massive undertaking required. Accountable Persons must retrospectively build a Golden Thread for these existing structures.
Gathering retrospective higher risk building information England often requires intrusive surveys, laser scanning to create new CAD/BIM models, and extensive fire risk assessments to recreate the data that should have been kept during the original construction. While daunting, this retrospective data gathering is important for high rise residential buildings in England, especially where accountable persons need reliable information to assess and manage building safety risks.
The implementation of the Building Safety Act represents a monumental, much-needed transformation in the UK construction and property sectors. The creation and maintenance of the Golden Thread is not merely an administrative burden; it is a life-saving methodology.
By demanding rigorous, precise building safety act drawings, detailed digital records, and strict accountability through the Gateway processes, the industry is moving away from a culture of value-engineering and opacity, toward one of quality, standardisation, and absolute transparency.
Whether you are a Principal Designer ensuring the early design information is compliant, a contractor using software like BricsCAD to document precise as-built conditions, or an Accountable Person curating the digital building record UK for the next fifty years, everyone has a part to play. Embracing these digital requirements, from detailed fire strategy plans to structural safety reports, is the only way to ensure our buildings are safe, project teams can better demonstrate how building safety information has been created, controlled, handed over and maintained, and, most importantly, the tragedies of the past are never repeated.
Question: What is the Golden Thread and who does it apply to?
Short answer: The Golden Thread is the complete, accurate, and secure digital information needed to understand a building and keep both the building and its occupants safe throughout its life. It must serve as a single source of truth, be accessible to the right people at the right time, and remain updateable via strict change control. It is a strict legal requirement for Higher-Risk Buildings (HRBs) in England—buildings at least 18 metres or seven storeys high, with at least two residential units. The Building Safety Regulator (BSR) can halt works, refuse occupation, and pursue prosecutions if the Golden Thread is missing or inadequate. Architects, engineers, contractors, the Principal Designer/Principal Contractor, and the Accountable Person all play roles in creating, curating, and maintaining it from concept to occupation and beyond.
Question: What drawings and digital records must be kept for compliance?
Short answer: You must maintain precise “as-built” building safety act drawings and a comprehensive set of digital records that together form the Golden Thread. Key items include:
Question: What is required at each Gateway, and what makes Gateway Two so demanding?
Short answer:
Question: How must design or product changes be managed during construction?
Short answer: All changes must go through formal, documented Change Control—no ad‑hoc on-site fixes. Changes are categorised as:
Question: What does a compliant handover look like at Gateway Three, including Regulation 38?
Short answer: Handover is a formal, regulated event. The Principal Contractor and Principal Designer must declare that the building was constructed in line with the approved Gateway Two design (plus any approved changes) and complies with Building Regulations. The Golden Thread must be handed over digitally, complete and ready for immediate use by the Accountable Person; if it’s incomplete or inaccurate, the BSR will refuse the completion certificate and occupation is unlawful. Regulation 38 requires the transfer of fire safety information at completion/first occupation—this goes beyond a generic manual and includes mandatory fire strategy plans, active/passive fire protection specs, commissioning certificates, and cause‑and‑effect data. As-built records must be literal (e.g., exact MEP routing, final structural layouts) and include linked photo evidence of concealed works, with O&M materials tied to digital assets for ongoing maintenance.
