What Gateway 2 is
Gateway 2 is the point at which the Building Safety Regulator has to approve the design of a higher-risk building before construction can lawfully begin. It replaced the old arrangement where a building could start on site with the design still developing and details resolved as they arose.
It is not a notification, a courtesy or a formality. Section 91 of the Building Safety Act 2022 prohibits starting higher-risk building work before building control approval is given. Starting anyway is an offence, not a programme decision.
Invalidation is not rejection, and it is the bigger problem
This distinction is the single most useful thing to understand about Gateway 2, because the two failures have completely different causes and completely different fixes.
| Invalidation | Rejection | |
|---|---|---|
| When | Before technical assessment | After technical assessment |
| Why | The application does not contain what the regulations require | The Regulator is not satisfied the design complies |
| The clock | Never started | Ran, and has now produced a decision |
| The fix | Administrative: assemble the package properly | Engineering: change the design or the justification |
A large proportion of closed applications have been invalidated rather than rejected. That is an uncomfortable statistic, because it means the most common Gateway 2 failure is not a design that is not good enough. It is a submission that was never complete enough to be looked at. And every one of those costs months.
What has to be in the application
The Building (Higher-Risk Buildings Procedures) (England) Regulations 2023 set the requirements. In practice the package has to include, at minimum:
- A fire and emergency file / fire strategy covering all of Requirements B1 to B5, with the design basis stated and every departure identified and justified.
- Plans and drawings at a scale and resolution that can be read and measured, consistent with the written strategy revision for revision.
- A competence declaration for the principal designer and the principal contractor, and evidence of competence for the individuals doing the work, not just the organisations.
- A construction control plan: how the work will be managed and controlled so that what gets built is what was approved.
- A change control plan: how major and notifiable changes will be identified, recorded and, where needed, submitted.
- A mandatory occurrence reporting procedure: how safety occurrences will be identified and reported.
- An information management / golden thread strategy: how the building's safety information will be created, kept current and handed on.
- A statement of how the design complies with the applicable functional requirements, not merely an assertion that it does.
The thing that trips teams up. Four of those items (competence declaration, construction control plan, change control plan, mandatory occurrence reporting procedure) are not fire engineering documents. They are process documents, they are usually nobody's obvious responsibility, and they are the ones most often missing when an application is invalidated.
The real change: design maturity
The demand Gateway 2 makes is not primarily for more documents. It is for the design to be finished, in a sense the industry has not previously required at that stage.
Under the old model, a strategy could say that cavity barrier locations would be confirmed at a later stage, that a smoke control system would be designed by a specialist under a performance specification, or that penetrations would be coordinated on site. Each of those is now a gap. The Regulator is assessing whether this design complies, and a design with holes in it cannot be assessed; it can only be queried.
Every query stops the clock. That is the mechanism by which a 12-week statutory period becomes a 22-week median.
What actually gets applications turned back
- Incomplete submission. A required document is missing or unnamed. Invalidated without assessment.
- Undeclared departures. The design goes outside the guidance and does not say so. Treated as an error.
- Drawings that disagree with the report. Different revisions, or details in one that contradict the other. The reviewer has to assume the worse case.
- Design basis not stated. A package that silently mixes Approved Document B and BS 9999 provisions and does not name an edition.
- Specification instead of design. A smoke control system named but not demonstrated. A performance requirement passed to a supplier who has not been appointed.
- Generic competence evidence. A company brochure where individual competence for this building type and height was required.
- External wall detail. Build-ups, junctions, cavity barriers and penetrations are the most heavily scrutinised part of the package, and the least often fully resolved at application.
- Unreadable drawings. Reviewers measure travel distances off your drawings. If the scale or resolution makes that impossible, they raise a query instead.
After approval: change control
Approval is not the end of the regime, it is the start of a different part of it. Once approved, changes are controlled. Major changes require a further application and approval before the changed work is carried out. Notifiable changes must be notified. Everything else must still be recorded in the golden thread.
The commercial consequence is direct: on a higher-risk building, late design change is no longer merely expensive, it is programme-critical in a way it was not before. Value engineering after Gateway 2 approval should be priced with that in mind.
Programming for it honestly
The statutory period is 12 weeks. Observed medians are around 22 weeks for new builds and around 35 weeks for external wall remediation. Programme against the observed figure, allow for at least one round of requests for information, and remember the clock only starts when the application is validated. The time spent getting the package accepted is on top.
Two behaviours help more than anything else: appoint the fire engineer early enough that the strategy leads the design rather than documenting it, and freeze the design before submitting rather than after.
Last reviewed 25 July 2026 against the editions named above. Standards are revised; check the current published edition before relying on anything here in a design.