Safety, Durability & Residual Risk Matrix

This document provides a comparative assessment of four inner-pane roof glazing options, evaluating their safety, durability and residual risk in overhead applications. For further specification guidance, see our information on appropriate glass types for roof glazing applications. It compares monolithic toughened glass, annealed laminated glass with standard and enhanced interlayers and heat-strengthened laminated glass, against criteria including impact performance, compliance with BS 6262-4 guidance, post-breakage retention, susceptibility to spontaneous nickel sulphide breakage, thermal stress resistance, handling vulnerability and lifecycle consequences of failure. The matrix highlights that laminated glass is generally preferred for overhead glazing because it is more likely to remain in position after breakage, thereby reducing safety risks and consequential costs. The document ultimately recommends heat-strengthened laminated glass with a thick interlayer as the preferred solution, offering the most robust balance of safety, durability, and risk mitigation for roof glazing applications.
The matrix compares laminated glass, toughened glass and heat-strengthened laminated glass to support roof glazing specification decisions for commercial and heritage projects.