The Building Safety Act 2022 introduced a deceptively simple requirement: maintain a golden thread of building information throughout the lifecycle of every higher-risk building. The information must be digital, structured, searchable, and accessible to those who need it. The Principal Accountable Person must demonstrate to the Building Safety Regulator that safety risks are being actively assessed and managed.
In practice, this is not a documentation exercise. It is a decision governance mandate.
What the golden thread actually requires
Section 88 of the Act requires prescribed building information — covering fire safety and structural safety — to be maintained in digital format from design through construction and into occupation. The Building Safety Regulator is targeting assessment of approximately 40 per cent of occupied higher-risk buildings by end of 2026. A Remediation Bill expected during 2026 will impose a legal duty on landlords to remediate buildings over 18 metres by end of 2029, backed by criminal prosecution and unlimited fines.
The Construction Leadership Council's golden thread guidance and the Building Safety Alliance toolkit both emphasise one point that many estate operators underestimate: the thread must be auditable. Organisations must demonstrate when information was created, updated, and by whom — and what decisions were made on the basis of that information.
Why dashboards do not satisfy the mandate
Most estate management companies have invested in BMS analytics. They can show alarm states, energy trends, and portfolio benchmarks. These are informational tools. They tell you what happened.
The golden thread requires an evidence trail showing why a building was prioritised for intervention, what the analysis found, what action was recommended, whether that recommendation was accepted or overridden, and what the outcome was. A dashboard displaying a temperature exceedance is not the same as a governed record showing that the exceedance was detected, triaged against competing priorities across the estate, and dispatched to a qualified engineer with documented rationale.
No major BMS analytics platform currently produces this kind of auditable decision trail. The market offers visibility. It does not offer governance.
Fragmented estates, no governed prioritisation
Consider the operational context. An estate management company oversees 300 to 500 buildings across a mixed-vendor BMS landscape — Niagara N4 on some sites, Honeywell Trend on others, Schneider and Siemens controllers elsewhere. Each BMS uses its own data model and alarm configurations. Operations directors cannot make consistent cross-estate comparisons.
The engineering skills shortage compounds the problem. The UK faces an annual shortfall of 59,000 engineers and technicians. Budgets are constrained by pain/gain share contract models that penalise underperformance. Sending a specialist to Building 47 means not sending one to Building 112. The golden thread does not simply ask that these decisions be made. It asks that they be evidenced.
What an evidence trail looks like
A governed evidence trail for a building triage decision links several records. Detection: which telemetry triggered the condition, against what baseline. Classification: the type and severity of the condition. Estate context: how this condition ranked against others across the portfolio, considering regulatory deadlines and contractual obligations. Policy check: whether the action fell within defined maintenance windows and budget thresholds. Recommendation: what was proposed, the supporting evidence, and what alternatives were considered. Execution: whether the recommendation was accepted or overridden, by whom, and with what outcome.
Each step, logged and retrievable. Not a data lake — a decision architecture.
Compliance timeline and enforcement
The regulatory trajectory is compressed. The Building Safety Regulator aims to assess 40 per cent of occupied higher-risk buildings by end of 2026. The Remediation Bill will make non-compliance a criminal matter.
The golden thread sits alongside at least eleven other concurrent compliance regimes — from Minimum Energy Efficiency Standards and Part L to ESOS Phase 3 action plans with board-level sign-off, legionella control under ACoP L8, F-gas leak recording, and fire safety obligations. Each has its own inspection cycle, data format, and evidence requirements.
No estate management company can maintain twelve parallel compliance workstreams through manual processes. The question is whether the technology layer above the BMS produces compliance evidence as a by-product of daily operations — or whether compliance remains a separate, retrospective exercise.
From analytics to contractually valuable intelligence
The distinction is not semantic. Analytics tells an operations director that chilled water delta-T across a portfolio averaged 3.2 degrees Celsius last month. Governed intelligence tells the same director that Building 47's chilled water plant has drifted 1.8 degrees from its commissioned baseline over 90 days, that the drift pattern matches a condenser fouling signature seen in three other buildings last quarter, and that Building 47 should be prioritised because its MEES review is due in four months and current performance puts its EPC rating at risk.
When that intelligence carries a full evidence trail — detection, classification, estate context, policy validation, outcome tracking — it becomes contractually valuable. It satisfies the golden thread. It supports ESOS board-level sign-off. It provides evidence for pain/gain share reporting. Building management shifts from reactive service to governed, auditable discipline.
What Aeterno builds
Aeterno provides a governed intelligence layer for building estates — sitting above existing BMS infrastructure and CAFM platforms, normalising data from mixed-vendor estates, and producing auditable decision trails for every triage, prioritisation, and dispatch action. The evidence trail is the product: every decision carries its inputs, its reasoning, and its outcome, meeting the golden thread mandate as a by-product of daily operations.