The Higher-Risk Building (HRB) regime

Spoke 2 of the Apex Insurance Brokers Building Safety Act 2022 hub. The HRB regime is the substantive heart of the new system; if you are designing, building or managing residential buildings, you need to know whether each project falls inside it.

Plain English summary

The Building Safety Act 2022 ("BSA 2022") created a separate regulatory regime for the highest-risk residential buildings — broadly, residential blocks of at least 18 metres or at least seven storeys. These are called Higher-Risk Buildings ("HRBs"). For HRB projects in England:

The Building Safety Regulator ("BSR"), sitting inside the Health and Safety Executive, is the building control body. Local authority building control no longer plays that role on these projects.
Three statutory gateways must be cleared — at planning (Gateway 1), pre-construction (Gateway 2) and pre-occupation (Gateway 3).
A "golden thread" of design and construction information must be maintained throughout the project life and handed over at completion.
Once occupied, the building has a separate in-occupation regime under Part 4 BSA 2022, with an "Accountable Person" required to register the building, prepare a safety case and manage risks on an ongoing basis.

The HRB definition at the design and construction stage is different from the one that applies in occupation. PI underwriters care about both — the design-and-construction definition because it determines whether the proposer's project work falls into the harder underwriting tier, and the in-occupation definition because it scopes liability for the Accountable Person role.

The market consequence: any time the words "higher-risk building" or "in-scope under the BSA dutyholder regime" appear in a project description, the proposal is reviewed by a different underwriter, against tighter wording, with longer disclosure requirements and (often) a sub-limit or aggregation cap.

The legal position

The BSA 2022 definition

Section 65 BSA 2022 defines a "higher-risk building" in the context of the design and construction provisions of Part 3 as a building of a description specified in regulations made by the Secretary of State. The relevant regulations are the Higher-Risk Buildings (Descriptions and Supplementary Provisions) Regulations 2023 (SI 2023/275).

SI 2023/275 specifies that a building is an HRB if:

It contains at least two residential units; and
It is at least 18 metres in height or has at least seven storeys (whichever is reached first).

The regulations define "storey" and "height" with detailed measurement rules — height is measured from the lowest level of the ground adjoining the outside of the building to the top of the floor surface of the topmost storey (ignoring rooftop plant rooms and machinery rooms not used as residential accommodation). The "two residential units" qualifier excludes single houses and small conversions.

The regulations also contain specific exclusions: secure residential institutions, military barracks, hotels, and certain types of hospital are not HRBs even if they meet the height threshold. Care homes, however, are in scope — a point of practical significance.

The in-occupation HRB definition

Part 4 BSA 2022 (sections 71–75) uses a slightly different definition for the in-occupation regime. The two definitions are aligned in the key dimensions (height/storey count and residential character) but the supplementary regulations and the boundary cases differ. Practitioners should not assume that a building in scope at design-and-construction stage is automatically in scope in occupation, or vice versa.

The three gateways

The HRB design and construction gateways are set out in the Higher-Risk Buildings (Procedures) (England) Regulations 2023 (SI 2023/909).

Gateway 1 — planning stage. Operating since 1 August 2021 (under earlier town and country planning provisions). A fire statement must accompany any planning application for an HRB, and statutory consultation with the Health and Safety Executive is required. Approval at this gate is a condition of planning permission for the HRB.

Gateway 2 — pre-construction. A building control application must be made to the BSR before construction works start. The application must include a detailed design and construction control plan (DCCP), a change control plan, a construction control plan, fire and emergency strategy, a competence declaration for the dutyholders, and full design drawings. The BSR has 12 weeks (extendable by agreement) to determine the application. Construction cannot start on the HRB until the BSR has approved Gateway 2.

The BSR has been candid in published statistics that first-time Gateway 2 approval rates have been low — well under 50% in many quarters — and that decision times have routinely exceeded the statutory 12-week target. Substantive deficiencies (incomplete fire strategy, inadequate change control, weak competence declaration) drive rejection. The market reality is that many HRB projects are delayed substantially at Gateway 2 — and the dutyholders bear the commercial cost of those delays, with knock-on implications for any time-sensitive PI exposure.

Gateway 3 — completion. Before the HRB can be occupied, the principal contractor and principal designer must submit a completion certificate application with full as-built information and an updated "golden thread" pack. The BSR must approve before the building can be lawfully occupied; an enforcement notice can be issued for any breach.

The "golden thread"

SI 2023/909 requires that a "golden thread" of accurate, accessible, structured digital information about the building be maintained throughout the design and construction phase and handed over at Gateway 3. The information must be kept under the regime through occupation, with the in-occupation Accountable Person responsible for it from then on. The golden thread is the documentary backbone of the post-Grenfell regime and is intended to make it possible to interrogate decisions made during design and construction for the life of the building.

Mandatory occurrence reporting

SI 2023/911 (the Building Regulations amendment regulations) and the parallel HRB provisions require dutyholders to report safety occurrences — situations where a structural failure or fire spread risk has occurred or could occur — to the BSR within prescribed timescales. This creates an additional documentary trail that PI insurers may later seek to interrogate.

The transitional cut-over

The HRB regime came into force on 1 October 2023 for new projects. Transitional provisions in SI 2023/909 allowed projects that had submitted an initial notice or full plans application to local authority building control before that date to continue under the previous regime, provided that "sufficient progress" was made within the transitional grace period. The Building Safety (Transitional Provisions) Regulations 2023 specified what "sufficient progress" meant. Many projects encountered transitional issues during 2024 and into 2025; the BSR has had to issue practice guidance on the boundary cases.

The PI implications

A separate underwriting tier

For most construction PI insurers, HRB design work now sits in a separate underwriting tier. The proposer is expected to identify HRB exposure expressly. Capacity is narrower, pricing higher, and the underlying wording often carries a specific HRB sub-limit or fire safety carve-out. See Spoke 6 — PI availability.

The gateway-related delay risk

Where a Gateway 2 rejection causes substantial project delay, the question of consultant liability for the rejection (was it the lead designer's fault that the fire strategy was inadequate?) becomes acute. Claims for time-related losses on HRB projects are an emerging area of dispute. Whether such losses are covered under the PI policy depends on the wording — most policies cover liability for damages, not all forms of consequential loss, and "delay" claims sit awkwardly with traditional PI cover. Always check the relevant exclusions (and any contractual limitation of liability you have in your appointment).

The competence declaration

The Gateway 2 application requires a written declaration that the principal designer and principal contractor have the necessary competence. This is a representation made to the BSR; it is also a representation that an insurer may interrogate at the point of claim if the project goes wrong. Misstating competence is a regulatory and reputational issue as well as an underwriting one.

The "golden thread" as a litigation document

The golden thread will, in due course, be the primary disclosure source in any litigation arising from an HRB. A complete, accurate, version-controlled golden thread is the dutyholder's best protection. An incomplete or inconsistent one is a litigation liability. PI underwriters increasingly ask whether the proposer has the systems to maintain a golden thread to the standard required.

Run-off and Part 4 overlap

The in-occupation regime under Part 4 BSA 2022 means that the Accountable Person has ongoing duties as long as the building is in occupation. For a designer or contractor who later becomes an Accountable Person under a development-and-hold model, this creates an indefinite PI tail with a fundamentally different risk profile from a transactional design-and-deliver model. See Spoke 4 — Principal Contractor exposure.

Worked scenario

Facts: A regional housebuilder is delivering a 22m residential block of 56 flats. The project is plainly an HRB. The architect is engaged as Principal Designer; a national D&C contractor is engaged as Principal Contractor.

The Gateway 2 submission is rejected at first attempt for: (i) inadequate fire strategy; (ii) incomplete change-control documentation; (iii) ambiguity in the cavity barrier specifications at junction details. The BSR requires a resubmission. The resubmission is approved at week 28 — a 16-week delay against the original programme.

The developer sues both the Principal Designer and the Principal Contractor for project delay losses of £1.2m. The Principal Designer notifies its PI insurer. The insurer accepts notification but flags that any indemnity for "delay" or "consequential loss" is excluded from the policy other than damages flowing from a covered breach.

Issues for the architect's PI:

The underlying breach (an inadequate fire strategy) is a professional services failure and within scope of PI.
The losses claimed are mixed: a portion is "rectification cost" (revising the strategy), a portion is "delay" (the 16 weeks of holding costs), and a portion is "extra-over construction cost" caused by the late design changes.
The PI cover will respond to the rectification element of damages, will respond to extra-over construction costs caused by the breach (subject to betterment arguments), and may or may not respond to pure delay/holding costs depending on the wording.
The architect's appointment includes a contractual limitation of liability at £5m and a net contribution clause — both relevant to the eventual quantum.

The point: HRB projects bring not only longer programmes but new categories of loss into play. The PI buyer needs to understand the interaction of the wording, the appointment, and the new regulatory hurdles.

Sector-specific practical takeaways

Architects and lead designers: the Gateway 2 fire strategy is the single highest-risk artefact in your scope. If you are not a fire engineer, do not sign it; engage a competent specialist, but make sure the appointment chain is clean and the collateral warranties are in place.

Structural engineers: the structural design submission at Gateway 2 is at unprecedented scrutiny. Calculation packs, design assumptions and load schedules are subject to BSR review. Insurers want assurance that your QA process matches the regime's expectations.

Fire engineers: every HRB Gateway 2 submission is a representation about the adequacy of the fire strategy. The market for PI on fire-engineering services is thin and demanding — be sure your scope is precisely defined and your run-off arrangements are robust.

Building surveyors: an EWS1 sign-off on an HRB is high-stakes. The EWS1 process and the BSA dutyholder regime overlap but are not the same; the underwriting consequences of doing one are very different from doing the other. Disclose both, separately and accurately, in your proposal.

D&C contractors: Gateway 2 is your hard stop on starting work. Build commercial protection into your programme assumptions; underestimating the gateway timing has been a frequent cause of dispute since 2023. See Spoke 4 — Principal Contractor.

Frequently asked questions

1. Is a 17m, 8-storey block an HRB? Yes. The 18m / 7-storey test is "whichever is reached first". An 8-storey building meets the storey test regardless of height. Measurement of storeys and height has technical rules under SI 2023/275.

2. Are care homes HRBs? Yes, if they meet the threshold. Care homes were specifically included in the HRB definition. Hospitals, hotels and secure residential institutions are excluded by the SI 2023/275 exclusion provisions.

3. Does the regime apply to refurbishment of existing HRBs? Yes. Building control approval is required for relevant works to an existing HRB just as it is for new construction. The Gateway 2 process applies, scaled to the scope of the works.

4. What happens if the building changes height during design? If the building rises through the threshold during design — for example, the storey count goes from 6 to 7 — it becomes subject to the HRB regime from that point, with potentially significant timing implications. Track this proactively.

5. Is there an appeal from a BSR Gateway 2 refusal? There is a regulatory appeals process under the Building Act 1984 as amended. Practically, most disputes are resolved through resubmission rather than appeal, but the formal route exists.

6. Who is the BSR for projects in Wales? Wales has a parallel but distinct regime. The Building (Approved Inspectors etc.) (Wales) Regulations and the Welsh Building Safety provisions take a different path; engagement is with the Welsh Ministers and Welsh registered building control approvers, not the BSR in England.

7. What does "two residential units" exclude? A single private dwelling (a single house) is excluded. The drafting is intended to take large detached houses and small conversions out of scope while keeping any block of flats or apartments in scope.

8. How is the "golden thread" defined in practice? The BSR has published guidance on what a compliant golden thread looks like — accurate, accessible, current, structured digital information. The standard expects version control, change tracking and capacity to interrogate the documents through the building's life. Many existing CDE / BIM workflows form a foundation but need supplementation to meet the regulatory standard.

9. Does the in-occupation Accountable Person regime apply to all HRBs? Yes, for HRBs in England, as defined under Part 4 BSA 2022 and the related regulations. The Accountable Person is usually the freeholder or the management company. Where there is more than one Accountable Person, one is the Principal Accountable Person and has overall responsibility.

10. Does the PI policy follow the Accountable Person role? PI cover is typically scoped to "professional services" provided by the policyholder. Operational duties as Accountable Person are not always within that scope; they may fall under a property owner's liability policy or a directors' and officers' policy. Check the wording — and see Spoke 4 for the contractor's position.

Sources

Statute — Building Safety Act 2022 c.30, ss.65, 71–75; Building Act 1984 c.55.

Secondary legislation — Higher-Risk Buildings (Descriptions and Supplementary Provisions) Regulations 2023 SI 2023/275; Higher-Risk Buildings (Procedures) (England) Regulations 2023 SI 2023/909; Building Regulations etc. (Amendment) (England) Regulations 2023 SI 2023/911.

Guidance — Building Safety Regulator: published guidance on Gateway 2 applications, "golden thread" expectations and competence requirements; HSE published statistics on Gateway 2 decision times and approval rates.

Reports — Building a Safer Future, Dame Judith Hackitt, May 2018.

Where this fits

Disclaimer

This is legal and insurance commentary, not advice. The Building Safety Act 2022 regime is technical and fact-sensitive — consult specialist counsel and your broker on your specific position. Apex Insurance Brokers Limited is authorised and regulated by the Financial Conduct Authority, FRN 724952.