Create and maintain the golden thread

What the golden thread is and why it matters

The golden thread is a comprehensive digital record of building information that must be created and maintained throughout the entire lifecycle of a higher-risk building - from initial design through construction to ongoing occupation.

The term reflects its purpose: an unbroken line of accurate, accessible information that connects every decision made about the building to every person who needs to understand or act on that information. When a fire breaks out, when maintenance is required, or when the Building Safety Regulator conducts an inspection, the golden thread provides the answers.

Incomplete or inaccessible records can lead to enforcement action, prevent you obtaining a completion certificate at Gateway 3, or create liability if building safety incidents occur.

Who is responsible for the golden thread

Responsibility for the golden thread shifts as the building progresses through its lifecycle. Understanding who holds responsibility at each phase - and when handover occurs - is critical to maintaining an unbroken chain of information.

Design phase: Principal Designer

During design, the Principal Designer must set up the digital information system before design work begins, recording all design decisions and the evidence supporting them. Coordinate with all design team members to capture information at the point decisions are made - retrospective gathering is expensive and error-prone.

Construction phase: Principal Contractor

When construction begins, responsibility transfers to the Principal Contractor. They must update records to reflect what is actually built (not just designed), record all changes and reasons, and capture test results, inspection records, and product certifications.

The gap between design and as-built is where many golden threads fail. The golden thread must reflect reality - not the original design.

Occupation phase: Accountable Person

Once occupied, the Accountable Person assumes permanent responsibility. This is a lifetime obligation that continues for as long as the building remains higher-risk.

Format requirements

The government does not mandate specific software for the golden thread - you can use any system that meets the regulatory requirements. However, the format requirements are strict and non-negotiable.

Key format principles

Paper records alone are not acceptable: the golden thread must be digital, although it can be spread across several systems if they are properly integrated. Explain technical terms in plain English, because residents have the right to understand their building's safety information. Record every change with who made it, when and why, and handle personal data in line with data protection law, including access controls and retention policies. The golden thread must transfer electronically without data loss, which matters for handovers and regulatory submissions.

Required content during design and construction

The golden thread during design and construction must capture information that explains what is being built and why. This is not simply a record of outputs - it must include the reasoning behind decisions.

Design information

• what was decided, and the evidence supporting each decision
• the fire safety strategy and how the design delivers it
• structural calculations, specifications and design rationale
• which materials were specified and why
• any changes from the original design, with the reasons

Construction information

• what was actually built, with variations from the design recorded
• certificates, specifications and test results for all safety-critical products
• quality assurance checks made during construction
• performance tests of fire safety and structural systems
• who did which work, with evidence of their competence

Required content during occupation

Once the building is occupied, the golden thread expands to include operational and safety management information. The occupation phase golden thread must be maintained and updated throughout the building's lifetime.

Ongoing updates

The golden thread is not static. During occupation, you must continuously update it to reflect:

• Maintenance carried out and repairs made
• Any modifications to the building structure or safety systems
• Updated fire risk assessments
• Changes to evacuation procedures
• Resident complaints about safety matters and how they were resolved
• Mandatory occurrence reports submitted to the Building Safety Regulator

Keep mandatory occurrence reporting records as part of the golden thread. Golden thread information must be retained for the lifetime of the building as a higher-risk building.

The handover process

Poor handovers are a common cause of golden thread failures. Well before completion, agree the handover format, timeline and acceptance criteria with the Accountable Person. Before transfer, check the golden thread is complete, make sure they can access and update it, and record the handover formally, signed by both parties. The Principal Designer and Principal Contractor should keep their own copies of the information they created.

Common mistakes to avoid

• Starting too late. The golden thread must be set up from day one of design; retrofitting means reconstructing decisions from memory and chasing contractors for discarded information.
• Recording outputs without reasoning. Storing drawings is not enough: the golden thread must explain why decisions were made.
• Treating it as an admin task. The person responsible needs to understand building design and fire safety, not just document filing.
• Using systems that do not integrate. When design and construction teams use different systems, information gets lost, so agree data formats and integration before work starts.
• Assuming BIM equals compliance. BIM can help but is not mandatory, and a BIM model alone does not guarantee the information types and version control the golden thread needs; a simpler document management system can work if it is set up properly.
• Writing only for specialists. Technical documents that only specialists can understand do not meet the requirement for residents to understand them.

Consequences of getting it wrong

Golden thread failures can have severe consequences at every phase of the building lifecycle.

Incomplete golden thread records will stop you getting a Gateway 3 completion certificate, which can delay a project by months. During occupation, Accountable Persons who fail to maintain the golden thread face compliance notices, improvement notices and ultimately special measures. If a safety incident occurs and the golden thread is incomplete, duty holders face greater liability, because the golden thread is their evidence of due diligence.

Next steps

If you are starting a new higher-risk building project, establish your golden thread system before design work begins. If you are taking over as Accountable Person for an existing building, audit the golden thread you receive at handover and identify any gaps that need remediation.

For existing occupied higher-risk buildings where the golden thread is incomplete, prioritise gathering the information required for your safety case report and Building Assessment Certificate application. The Building Safety Regulator can provide guidance on remediation priorities.