Glossary

The Building Safety Act runs on defined terms, and getting them wrong is how projects get the regime wrong. 50 of them, in plain English, each written the way a practitioner would explain it on site.

A

Accountable Person: The organisation or person who owns or has a repairing obligation for the common parts of an occupied higher-risk building. Accountable persons must assess and manage building safety risks, principally fire spread and structural failure, on an ongoing basis. Where a building has several, one is designated the principal accountable person.See also: Principal Accountable Person (PAP), Higher-Risk Building, Safety Case Report
Approval with Requirements: One of three possible Gateway 2 outcomes, alongside full approval and rejection. The Building Safety Regulator approves the application but attaches requirements, typically to provide further information or resolve specified matters before or as the relevant work proceeds. Each requirement must then be discharged as the build progresses.See also: Gateway 2, Building Control Approval, Building Safety Regulator (BSR)
As-built information: Plans and documents that record what was actually constructed, not what was designed. A valid Gateway 3 application must include as-built information reflecting the finished building. Discrepancies between as-built drawings and the systems or materials actually installed are one of the Building Safety Regulator's named reasons Gateway 3 applications stall.See also: Gateway 3, Golden Thread, Compliance Declaration

B

Batching: A Building Safety Regulator process, piloted between September and December 2025, in which groups of Gateway 2 applications are bundled and assessed by external specialist assessors under BSR oversight. Batching helped clear the new-build backlog and delivered median determination times of 12-14 weeks, with some approvals inside the statutory 12.See also: Gateway 2, Innovation Unit, Building Safety Regulator (BSR)
Building Assessment Certificate (BAC): A certificate issued by the Building Safety Regulator confirming that the accountable persons for an occupied higher-risk building are meeting their occupation-phase duties. The principal accountable person applies when directed by the regulator, submitting the safety case report and evidence of resident engagement and mandatory occurrence reporting systems.See also: Principal Accountable Person (PAP), Safety Case Report, Resident Engagement Strategy
Building Control Approval: The Building Safety Regulator's formal approval of a Gateway 2 application, granted as the building control authority for higher-risk buildings in England. Construction cannot lawfully start without it. Outcomes are approval, approval with requirements, or rejection, and dutyholders must give the BSR five working days notice before starting work.See also: Gateway 2, Approval with Requirements, Building Safety Regulator (BSR)
Building Regulations Compliance Statement: A Gateway 2 application document explaining how the proposed design complies with each applicable requirement of the Building Regulations, including where compliance relies on guidance, testing or engineered solutions. It gives the regulator a route map through the design information and is one of the documents CLC guidance now templates.See also: Gateway 2, Construction Control Plan, Fire and Emergency File
Building Safety Case: The body of evidence an accountable person holds to show that building safety risks in an occupied higher-risk building, principally fire spread and structural failure, have been identified and are being managed so far as reasonably practicable. It is summarised for the regulator in the safety case report.See also: Safety Case Report, Accountable Person, Building Assessment Certificate (BAC)
Building Safety Levy: A levy on new residential development in England, in force from 1 October 2026, that funds the remediation of historical building safety defects. It bites at building control: the Building Safety Regulator will not issue a Gateway 3 completion certificate where levy payment is overdue, so unpaid levy blocks occupation.See also: Gateway 3, Gateway 2
Building Safety Regulator (BSR): The regulator created by the Building Safety Act 2022 to oversee higher-risk buildings in England. It has been the building control authority for all HRBs since 1 October 2023, running Gateways 2 and 3, and became a standalone public body sponsored by MHCLG on 27 January 2026.See also: Gateway 2, Gateway 3, MHCLG

C

Change Control Log: The record of every controlled change made to a higher-risk building project between Gateway 2 approval and Gateway 3, capturing what changed, why, its compliance impact and who authorised it. Weak change control records are one of the Building Safety Regulator's four named reasons Gateway 3 applications stall.See also: Controlled Change, Major Change, Notifiable Change
Client (BSA): The dutyholder for whom higher-risk building work is carried out. Under Part 2A of the Building Regulations the client must make suitable arrangements for compliance, appoint a principal designer and principal contractor, and sign the client statement submitted with the Gateway 2 application accepting its dutyholder obligations.See also: Dutyholder, Principal Designer (BSA), Principal Contractor (BSA)
Competence Declaration: A signed declaration, submitted with a Gateway 2 application, in which the client confirms that appointed dutyholders have the skills, knowledge, experience and behaviours, or organisational capability, that their roles demand. It puts competence on the record before construction and is a standing requirement of the dutyholder regime.See also: Dutyholder, Client (BSA), Gateway 2
Compliance Declaration: A signed declaration required at Gateway 3 in which the principal designer and principal contractor each confirm that, to the best of their knowledge, the completed work complies with Building Regulations. It attaches personal professional accountability to the completion certificate application and cannot sensibly be signed without evidence.See also: Gateway 3, Principal Designer (BSA), Principal Contractor (BSA)
Construction Control Plan: A Gateway 2 application document setting out how compliance will be managed during construction: site supervision arrangements, inspection and test regimes, competence management, change control procedures and how the golden thread will be kept current. The Building Safety Regulator assesses whether the plan is credible before approving a start on site.See also: Gateway 2, Golden Thread, Controlled Change
Controlled Change: Any change to an approved higher-risk building design between Gateways 2 and 3 that must pass through the change control process. Controlled changes split into major changes, which need Building Safety Regulator approval before the affected work proceeds, and notifiable changes, which proceed unless the regulator objects within 14 days.See also: Major Change, Notifiable Change, Change Control Log

D

Dutyholder: Any of the roles carrying legal duties for building regulations compliance under Part 2A of the Building Regulations, in force since 1 October 2023: the client, principal designer, principal contractor, and every designer and contractor. Each must be competent for its role and cooperate to plan, manage and monitor compliance.See also: Client (BSA), Principal Designer (BSA), Principal Contractor (BSA)

F

Fire and Emergency File: A Gateway 2 application document capturing the fire safety information for a higher-risk building: the fire strategy, the systems provided and the assumptions the design relies on. It is maintained through construction, forms part of the golden thread, and is handed to the accountable person for the occupation phase.See also: Gateway 2, Golden Thread, Fire Statement
Fire Statement: The fire safety document submitted with a planning application at Planning Gateway One, required since August 2021 for relevant high-rise residential buildings. It sets out fire safety considerations at a level appropriate to planning, such as site access for fire appliances, and is reviewed by the regulator as statutory consultee.See also: Planning Gateway One, Gateway 1, Relevant Building
First-tier Tribunal: The tribunal, through its Property Chamber, that decides most Building Safety Act disputes in England: applications for remediation orders and remediation contribution orders, leaseholder protection disputes, and appeals against Building Safety Regulator decisions. For practitioners it is where the Act's civil enforcement teeth are actually applied.See also: Remediation Order, Remediation Contribution Order, Qualifying Lease

G

Gateway 1: The planning-stage checkpoint of the higher-risk regime, live since August 2021. A fire statement must accompany the planning application for relevant high-rise residential buildings, with the regulator acting as statutory consultee on fire safety. Hospitals and care homes are excluded at this stage despite being HRBs at Gateways 2 and 3.See also: Planning Gateway One, Fire Statement, Gateway 2
Gateway 2: The hard stop before construction of a higher-risk building. Building control approval must be obtained from the Building Safety Regulator before work can lawfully start. Statutory determination is 12 weeks for new builds and 8 weeks for work to existing HRBs; fees are 195 pounds plus 156 pounds per hour per assessor.See also: Building Control Approval, Gateway 3, Staged Application
Gateway 3: The hard stop before occupation of a higher-risk building. A completion certificate application goes to the Building Safety Regulator once notifiable work is complete; statutory determination is 8 weeks and fees are 189 pounds plus 151 pounds per hour. Occupying before the certificate is issued and the building registered is a criminal offence.See also: Gateway 2, As-built information, Partial Completion Certificate
Golden Thread: The digital, accurate and accessible record of a higher-risk building's design, construction and safety information, created at Gateway 2, maintained through every change during the build, and handed to the accountable person at Gateway 3. It exists so anyone managing the building can understand it and keep it safe.See also: Gateway 3, As-built information, Accountable Person

H

Hackitt Review: Dame Judith Hackitt's Independent Review of Building Regulations and Fire Safety, commissioned after Grenfell. Its May 2018 final report, Building a Safer Future, found a race to the bottom in building standards and recommended the gateways, dutyholder accountability, the golden thread and a single regulator that became the Building Safety Act 2022.See also: Golden Thread, Dutyholder, Building Safety Regulator (BSR)
Higher-Risk Building: In England, a building at least 18 metres tall or with at least 7 storeys, containing at least two residential units. Hospitals and care homes meeting the height threshold are higher-risk buildings at design and construction stage. HRBs are subject to Gateways 2 and 3 and BSR building control.See also: Gateway 2, Gateway 3, HRB Register
HRB Register: The Building Safety Regulator's register of occupied higher-risk buildings in England. Existing HRBs had to be registered by 30 September 2023; new buildings must be registered by the principal accountable person before occupation. For new HRBs, occupation without both registration and a Gateway 3 completion certificate is a criminal offence.See also: Principal Accountable Person (PAP), Higher-Risk Building, Gateway 3

I

Innovation Unit: A Building Safety Regulator unit created in the June 2025 reforms to process new-build Gateway 2 applications faster. In the 12 weeks to 30 May 2026 it was running at a 90% approval rate, against 75% across all Gateway 2 decisions, and it helped break the legacy backlog.See also: Gateway 2, Batching, Building Safety Regulator (BSR)

K

Key Building Information: Structured information about an occupied higher-risk building that the principal accountable person must submit to the Building Safety Regulator after registration and keep up to date: matters such as structure, materials, fire safety provisions and use. It gives the regulator a risk profile of the occupied HRB stock.See also: Principal Accountable Person (PAP), HRB Register, Higher-Risk Building

L

Landlord Certificate: The certificate a landlord of a relevant building must provide to leaseholders setting out whether the landlord, or an associated company, is responsible for relevant historical safety defects and whether it meets the Act's contribution conditions. It determines what remediation costs, if any, can be passed to qualifying leaseholders.See also: Qualifying Lease, Leaseholder Deed of Certificate, Relevant Building
Leaseholder Deed of Certificate: The certificate a leaseholder in a relevant building completes to evidence whether their lease is a qualifying lease under the Building Safety Act's leaseholder protections. It records the position at the qualifying time and feeds the landlord certificate process that decides how remediation costs can lawfully be apportioned.See also: Qualifying Lease, Landlord Certificate, Relevant Building

M

Major Change: A controlled change significant enough to require Building Safety Regulator approval before the affected work can proceed, typically taking 4-6 weeks, with work on the affected area stopped in the meantime. Major changes are the heavyweight tier of change control between Gateways 2 and 3 and must be fully evidenced.See also: Controlled Change, Notifiable Change, Change Control Log
Mandatory Occurrence Reporting: The system dutyholders and accountable persons must operate to report safety occurrences on higher-risk buildings to the Building Safety Regulator: incidents or risks that could cause death or serious injury from fire spread or structural failure. A mandatory occurrence reporting plan is a required part of every Gateway 2 application.See also: Gateway 2, Dutyholder, Building Safety Regulator (BSR)
MHCLG: The Ministry of Housing, Communities and Local Government, the department that owns building safety policy in England. Since 27 January 2026 it has sponsored the Building Safety Regulator as a standalone public body, a step toward the single construction regulator recommended by the Grenfell Inquiry Phase 2 report.See also: Building Safety Regulator (BSR)

N

Notifiable Change: A controlled change that must be notified to the Building Safety Regulator but can proceed unless the regulator objects within 14 days. Less serious than a major change, it still has to be recorded in the change control log with its compliance justification, because weak change records stall Gateway 3 applications.See also: Controlled Change, Major Change, Change Control Log

P

Partial Completion Certificate: A Gateway 3 completion certificate covering part of a higher-risk building, allowing that part to be occupied while work continues elsewhere. It is only available where a partial completion strategy was agreed with the Building Safety Regulator at Gateway 2, and it is not generally suitable for individual flats or floors.See also: Gateway 3, Gateway 2, Staged Application
Planning Gateway One: The formal name for Gateway 1, in force since August 2021. Fire statements accompany planning applications for relevant high-rise residential buildings, and the Health and Safety Executive acts as statutory consultee on fire safety to the local planning authority. It front-loads fire thinking before land deals harden the design.See also: Gateway 1, Fire Statement
Principal Accountable Person (PAP): Where an occupied higher-risk building has more than one accountable person, the one responsible for the structure and exterior. The PAP registers the building, submits key building information, prepares the safety case report and resident engagement strategy, and applies for the building assessment certificate when directed by the regulator.See also: Accountable Person, HRB Register, Safety Case Report
Principal Contractor (BSA): The dutyholder in control of the construction phase of higher-risk building work under Part 2A of the Building Regulations. Distinct in law from the CDM principal contractor, though usually the same firm, it must plan, manage and monitor compliance on site and sign the Gateway 3 compliance declaration.See also: Dutyholder, Principal Designer (BSA), Compliance Declaration
Principal Designer (BSA): The dutyholder in control of the design phase of higher-risk building work under Part 2A of the Building Regulations. It must plan, manage and monitor design work so the design, if built, would comply with Building Regulations, and it signs the compliance declaration submitted at Gateway 3.See also: Dutyholder, Principal Contractor (BSA), Compliance Declaration

Q

Qualifying Lease: A long lease of a single dwelling in a relevant building that met the Building Safety Act's conditions at the qualifying time, including the property being the leaseholder's principal home or one of a limited number of owned properties. Qualifying leaseholders receive statutory protections limiting historical safety remediation costs.See also: Relevant Building, Landlord Certificate, Leaseholder Deed of Certificate

R

Registered Building Inspector (RBI): A building control professional registered with the Building Safety Regulator, the qualification required to carry out restricted building control work in England. On higher-risk buildings, RBIs work within the BSR's multi-disciplinary teams alongside fire and structural specialists rather than acting as the standalone approver of the old regime.See also: Building Safety Regulator (BSR), Higher-Risk Building
Relevant Building: A term the Building Safety Act uses in two contexts. At Planning Gateway One it means the high-rise residential buildings needing a fire statement. In the Part 5 leaseholder protections it means residential buildings above a lower height threshold than higher-risk buildings, whose qualifying leaseholders are protected from historical remediation costs.See also: Qualifying Lease, Higher-Risk Building, Planning Gateway One
Remediation Contribution Order: A First-tier Tribunal order requiring a landlord, developer or associated company to contribute to the costs of remedying relevant defects in a relevant building. It lets interested parties, including leaseholders and regulators, pursue the parties who caused or profited from defects rather than those who merely live with them.See also: Remediation Order, First-tier Tribunal, Relevant Building
Remediation Order: A First-tier Tribunal order requiring a relevant landlord to remedy specified relevant defects in a relevant building within a set time. It is the direct enforcement route for getting unsafe buildings fixed, and can be sought by leaseholders, regulators and other interested persons under the Building Safety Act.See also: Remediation Contribution Order, First-tier Tribunal, Relevant Building
Resident Engagement Strategy: The strategy a principal accountable person must prepare for an occupied higher-risk building setting out how residents will be given building safety information, consulted on decisions that affect them, and able to raise concerns and complaints. It is assessed as part of the building assessment certificate process.See also: Principal Accountable Person (PAP), Building Assessment Certificate (BAC), Accountable Person

S

Safety Case Report: The document summarising an occupied higher-risk building's safety case: the building safety risks identified, principally fire spread and structural failure, and the evidence that they are being managed. The principal accountable person produces it and submits it to the Building Safety Regulator when applying for a building assessment certificate.See also: Building Safety Case, Principal Accountable Person (PAP), Building Assessment Certificate (BAC)
Second Staircase Mandate: The requirement that all new residential buildings in England above 18 metres include a second staircase, in force from 30 September 2026 with transitional provisions for sufficiently progressed schemes. Designs already in the Gateway 2 pipeline have had to be checked, and in some cases reworked, against it.See also: Gateway 2, Higher-Risk Building
Staged Application: A Gateway 2 application made in stages, letting groundworks and substructure be approved and started before the superstructure design is signed off. Originally for complex multi-building schemes, staged applications were extended to single-tower higher-risk buildings in December 2025 and are now a standard programme-protection tactic for developers.See also: Gateway 2, Building Control Approval
Stop Notice: An enforcement notice from the Building Safety Regulator requiring work on a higher-risk building to stop until specified serious non-compliance is put right. Breaching a stop notice is a criminal offence. It sits alongside compliance notices and prosecution in the regulator's enforcement toolkit for gateway and building regulations breaches.See also: Building Safety Regulator (BSR), Gateway 2, Gateway 3