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The golden thread under the Building Safety Act: keeping compliant digital records from design to handover

The golden thread is the digital record that shows a higher-risk building in England was designed and built to comply with building regulations, and that lets those responsible manage its safety once occupied. During design and construction the client must keep it in an electronic facility that designers and contractors can reach, record every controlled change and pass it to the accountable person by completion. This page sets out the rules and where software can help.

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On this page
  1. Which buildings are higher-risk, and who holds the duties
  2. The instruments that define the golden thread for higher-risk buildings
  3. Golden thread information from building control approval to occupation
  4. Change control for a notifiable change during construction
  5. Requirements a golden thread facility must meet during the works
  6. Where structured data, AI checks and tamper-evident logs fit
  7. A hypothetical design change during residential tower fit-out
  8. Questions and answers
  9. Sources

Which buildings are higher-risk, and who holds the duties

For design and construction, a higher-risk building in England is one that is at least 18 metres in height or has at least 7 storeys2 and that contains at least two residential units, or is a care home or a hospital3. The regime was introduced by the Building Safety Act 20221, and since January 2026 the Building Safety Regulator has operated as a standalone public body sponsored by the Ministry of Housing, Communities and Local Government rather than as part of the Health and Safety Executive8.

The information duties fall on named parties. The client sets up and maintains the golden thread facility during the work; the principal designer and principal contractor run the mandatory occurrence reporting system; and the principal contractor keeps the change control log45. Once the building is occupied, the accountable person keeps and provides the prescribed information6.

The instruments that define the golden thread for higher-risk buildings

Building Safety Act 2022[^1]

UK (higher-risk regime in England)

Applies whenA building meets the higher-risk definition and is being designed, built or occupied1.

  • Establishes the Building Safety Regulator and the higher-risk building regime
  • Creates accountable person duties for occupied buildings
  • Provides powers for the detailed regulations below

Higher-Risk Buildings (Descriptions and Supplementary Provisions) Regulations, SI 2023/275

England

Applies whenDeciding whether a building meets the height and use conditions in section 120D of the Building Act 19843.

  • Specifies buildings with at least two residential units, care homes and hospitals
  • Sets out how height and storeys are determined and which buildings are excluded

Building (Higher-Risk Buildings Procedures) (England) Regulations, SI 2023/909

England

Applies whenHigher-risk building work needs building control approval, changes during construction or completion certification4.

  • Building control approval applications before work starts, known as Gateway 24
  • Change control: change control log, notifiable changes and major change applications5
  • Golden thread facility kept electronically by the client
  • Mandatory occurrence reporting system and reports to the regulator
  • Completion certificate applications, known as Gateway 3, and handover of information4

Higher-Risk Buildings (Keeping and Provision of Information etc.) (England) Regulations, SI 2024/41

England

Applies whenAn occupied higher-risk building has an accountable person6.

  • Keep prescribed information on compliance, fire and structural safety and safety case material
  • Provide information to the regulator, other accountable persons, residents and others on request

Regulation (EU) 2024/3110 (Construction Products Regulation)

EU

Applies whenA manufacturer places construction products on the EU market9.

  • Combines the declaration of performance and the declaration of conformity
  • Provides for product information to be made available through a digital product passport system

Golden thread information from building control approval to occupation

The Building Safety Regulator describes three statutory gateways, at planning, before building work starts and at completion8. This table covers the last two and what follows.

StageInformation the thread must holdWho is responsibleWhere software helps
Building control approval applicationDesign, fire statement, competence and control plans submitted for approvalClient, with principal designer and principal contractorCompleteness checks against the application requirements
During constructionApproved plans, compliance evidence, controlled changes, dutyholder notices, occurrence reports4Client keeps the facility; principal contractor keeps the change logChange classification prompts, cross-document consistency checks, audit logs
Completion certificate applicationAs-built information and evidence that the work compliesClient, with both principal dutyholdersGap reports comparing evidence held against what was approved
HandoverGolden thread and fire safety information in its original filing structure, readable and updatable4Client hands over; relevant person acknowledges receiptExport validation, structure checks, receipt tracking
OccupationPrescribed information kept and provided on request6Accountable personSearch, access control, resident information requests

Change control for a notifiable change during construction

proposed changelog and classifyrevised documentsgap check resultnotice for signaturenotify before workinfo request, if anyrecord notice01Designer02Principalcontractor03Golden threadfacility04Client05Building SafetyRegulator
  1. Designer

    Proposes the change and revises the affected design documents.

  2. Principal contractor

    Records the change in the change control log with reasons and a compliance explanation.

  3. Golden thread facility

    Holds the revised documents and logs who changed what and when.

  4. Client

    Signs the notification and keeps the facility up to date.

  5. Building Safety Regulator

    Receives the notice and may ask for further information.

  1. Designer to Principal contractorproposed change
  2. Principal contractor to Principal contractorlog and classify
  3. Principal contractor to Golden thread facilityrevised documents
  4. Golden thread facility to Principal contractorgap check result
  5. Principal contractor to Clientnotice for signature
  6. Client to Building Safety Regulatornotify before work
  7. Building Safety Regulator to Clientinfo request, if any
  8. Client to Golden thread facilityrecord notice
Conceptual sequence based on the change control provisions for a notifiable change. A major change instead needs a change control application approved before work proceeds. The gap check is an optional software step, not a legal requirement.

Requirements a golden thread facility must meet during the works

Drawn from the client's duty under the 2023 procedures regulations4. Use it to test a CDE or document system before relying on it.

0 of 8 checked

Where structured data, AI checks and tamper-evident logs fit

Projects already working to ISO 19650 information management have a head start: a common data environment with naming, status and approval workflows covers much of what the facility needs. The government's golden thread principles, which include a single source of truth and accurate, trusted, accessible and durable information, point the same way7.

AI earns its place in checking rather than deciding. It can compare the change control log with revised documents to find changes that were logged but whose fire strategy or compartmentation drawings were never updated, flag occurrence-like language in site diaries for a person to assess, and test a handover export against the agreed structure. Classifying a change as recordable, notifiable or major, and deciding whether something is a safety occurrence, remain judgments for the duty holders.

A tamper-evident log adds independent proof of when each record version existed. ColdAI uses Hedera Consensus Service to anchor audit trails where outside parties need cryptographic proof of when and in what order something happened10. Anchoring a hash of each version keeps the documents in the facility while making later alteration detectable. It does not prove the content was correct, and it does not replace the facility the regulations require.

A hypothetical design change during residential tower fit-out

Questions and answers

Who is responsible for the golden thread during construction of a higher-risk building?

The client must establish and maintain the electronic facility that holds golden thread information and make sure designers and contractors can access it. The principal contractor keeps the change control log, and the principal designer and principal contractor operate the mandatory occurrence reporting system. On completion, the client hands the information to the accountable person, who keeps it during occupation.

Does a common data environment satisfy the golden thread requirements?

It can form the facility if it meets the regulatory requirements: electronic storage that transfers without loss, accurate and current content, readability, prompt access for principal dutyholders, security, a record of who changed what and when, and consistent terminology. The handover must also preserve the original filing structure. Test the CDE against each requirement rather than assuming compliance.

Can AI decide whether a change is notifiable or major under the Building Safety Act?

No. Software can prompt the team with the relevant criteria, compare the proposal with the categories set out in the regulations and highlight documents that need revising. Classifying the change, consulting the right people and signing notices or applications are responsibilities of the client and principal dutyholders, who remain accountable to the Building Safety Regulator.

Does the EU Construction Products Regulation affect projects in England?

The regulation applies to products placed on the EU market, so it matters most to manufacturers and suppliers selling into the EU. Its combined declaration and digital product passport approach may still make structured product data easier to bring into a golden thread for projects in England. Confirm which product rules apply to your supply chain with your advisers.

Sources

  1. Building Safety Act 2022 — legislation.gov.uk · checked 10 October 2026
  2. Building Act 1984, section 120D: meaning of higher-risk building — legislation.gov.uk · checked 10 October 2026
  3. The Higher-Risk Buildings (Descriptions and Supplementary Provisions) Regulations 2023, regulation 2 — legislation.gov.uk · checked 10 October 2026
  4. The Building (Higher-Risk Buildings Procedures) (England) Regulations 2023, Part 4: golden thread, mandatory occurrence reporting and information handover — legislation.gov.uk · checked 10 October 2026
  5. The Building (Higher-Risk Buildings Procedures) (England) Regulations 2023, Part 3: change control — legislation.gov.uk · checked 10 October 2026
  6. The Higher-Risk Buildings (Keeping and Provision of Information etc.) (England) Regulations 2024 — legislation.gov.uk · checked 10 October 2026
  7. Building Regulations Advisory Committee: golden thread report — GOV.UK · checked 10 October 2026
  8. Building Safety Regulator strategic plan 2026 to 2027 — GOV.UK · checked 10 October 2026
  9. Regulation (EU) 2024/3110 laying down harmonised rules for the marketing of construction products — EUR-Lex · checked 10 October 2026
  10. Hedera Consensus Service (HCS) — ColdAI

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