The Building Safety Act 2022 introduced a new safety framework for higher risk residential buildings in England. At the centre of the legislation are three gateways that control how a building moves from planning through to occupation.
The final stage, Gateway Three, is where the project team must demonstrate that the building has been designed and constructed in full compliance with building regulations. In simple terms, it confirms that the building is safe to occupy before residents can move in.
For developers and project teams, this stage is critical to completion. It requires clear evidence, coordinated documentation and a complete record of how safety has been managed throughout the build.
For consultants like CDC, Gateway Three is where early technical coordination proves its value. This article explains what the stage involves in practice and how CDC can help project teams prepare for well-coordinated submission.
What developers must provide at Gateway Three
To secure approval at Gateway Three, developers must submit a completion certificate application to the Building Safety Regulator. The application needs to demonstrate clearly that the completed building complies with all relevant parts of the building regulations. If satisfied, the Building Safety Regulator will issue a Completion Certificate, allowing the building to be legally occupied.
The regulator will assess whether the building as constructed aligns with the approved design intent and meets required safety standards.
To do this, the project team must provide a coordinated set of technical information and supporting evidence.
This typically includes:
- Accurate as built information, showing how the buildings have been constructed in practice.
- Technical evidence relating to fire and structural safety, including calculations, specifications, and supporting documentation that demonstrates compliance.
- A complete “golden thread” record, providing a clear and accessible digital history of the building’s design decisions, safety strategy, and construction details.
- Confirmation that the “golden thread” information has been handed over to the dutyholders responsible for managing the building once it is occupied.
- Clear change management records, demonstrating how any design, product or specification changes made after Gateway Two were reviewed, approved and properly documented.
For many teams, the challenge is not producing these documents individually. The difficulty lies in ensuring that they’re consistent, coordinated, and fully aligned with what has been installed on site.
When information is incomplete, inconsistent or prepared too late, the Gateway Three review process can slow significantly – and without approval, a higher-risk building cannot legally be occupied.
Common issues that delay Gateway Three approval
Because Gateway Three is still relatively new, many project teams are only now experiencing the full requirements of the process. Early applications have shown that delays are rarely caused by a single issue. More often, they arise when technical information has not been coordinated or maintained consistently throughout construction.
Several themes tend to appear in projects where Gateway Three approval takes longer than expected.
Incomplete or fragmented safety documentation
Applications can stall when key evidence relating to fire or structural safety is missing, unclear or inconsistent. In some cases, the information exists but sits across multiple consultants, contractors or subcontractors without being brought together into a clear and coherent submission.
Weak change management during construction
Design development and product substitutions are common during construction. However, where these changes are not properly recorded or assessed against the original strategy, it can become difficult to demonstrate that the completed building still complies with the approved design intent.
Unclear responsibility between dutyholders
Gateway Three applications can be delayed where it is not clear who is responsible for compiling, reviewing, and signing off specific elements of the submission. Clear allocation of responsibilities between the client, principal contractor and principal designer is essential.
Systems that have not been reviewed together
Safety critical systems may perform correctly when tested individually, but issues can arise when they interact within the completed building. Ensuring that fire safety measures, structural systems and building service operate effectively together is an important part of the final verification process.
In many cases, these challenges are not the result of poor design or construction. They arise because information has been gathered late or managed across multiple parties without clear coordination.
How early oversight can make a difference
When disciplines work in isolation, documentation can become fragmented. Design decisions may be made at different stages by different parties, and the link between those decisions and the final as-built record can become unclear. By the time the Gateway Three submission is being prepared, project teams may then need to retrace steps to confirm how systems were designed, installed and approved.
Early technical coordination helps avoid this situation. When key disciplines collaborate from the outset, it becomes much easier to maintain a consistent record of design intent, safety strategy and construction outcomes throughout the project.
For CDC, this coordinated approach is central to how we support project teams. By bringing together expertise in fire safety engineering, acoustic design, facade engineering and building surveying, we can review how building systems operate effectively together as part of the completed building.
In practice, this means helping teams:
- Review design information early to identify potential compliance risks
- Maintain clear and consistent technical documentation throughout construction
- Assess design or product changes against the approved safety strategy
- Ensure the completed building aligns with the approved design and regulatory requirements.
By maintaining clear records and coordinated oversight throughout the build, the Gateway Three submission becomes far more straightforward. Instead of assembling evidence at the end of the project, the information required for approval already exists as part of the project record.
Preparing for Gateway Three with confidence
Gateway Three represents a legal threshold, not a formality, requiring demonstrable evidence that safety has been properly managed throughout design and construction.
CDC works alongside developers, architects and contractors to help manage this process. Through coordinated technical advice and clear documentation, we support project teams in navigating Gateway Three with confidence. We can support responding to Building Safety Regulator queries, coordinating technical responses, and helping avoid late-stage redesign or rework that can impact programme and cost.
Our integrated team helps create a clearer submission process and greater certainty at the point of occupation.
Get in touch with the team by calling +441206 809 598 or sending an enquiry online today.
