Chapter 17: Klasse
How the BSA and Gateway 2 impact through-wall construction

Klasse explores how Gateway 2 has changed compliance requirements for through-wall construction in high-risk UK buildings

The introduction of the Building Safety Act 2022 represents a fundamental shift in how high-risk buildings are designed, constructed and managed in the UK. With the rollout of Gateway 2, a key checkpoint within the new regulatory regime, specifiers, designers and contractors must now engage with compliance in more structured and transparent ways. One of the areas most impacted by this change is through-wall construction.

Gateway 2: A new compliance milestone

Gateway 2, which came into force in October 2023, acts as a planning threshold at the pre-construction phase for higher-risk buildings (HRBs). Before any building work begins, full design details must be submitted to the Building Safety Regulator (BSR) for approval. This includes all aspects of the external wall system with no exceptions.

Additionally, specifiers must ensure that the system has appropriate third-party testing and certification. Reliance on desktop studies or assumptions of equivalence is increasingly risky under Gateway 2 scrutiny. This change places a premium on early collaboration between product manufacturers, design teams and compliance consultants.

Raising the standard for safety and accountability

Ultimately, Gateway 2 enforces a cultural shift toward accountability in construction. It requires specifiers to make design decisions that are not just compliant in theory, but also provable in practice. Through-wall systems are central to that effort, both as a safety-critical component and as a symbol of how regulatory reform is reshaping best practice.

Want to learn more? Book Klasse's CPD ‘Specifying Compliant Through Wall Systems Used With External Facades’, where the company explores the BSA and Gateway 2 as part of the seminar content.

www.klassegroup.co.uk