Structural Glass Calculator

Structural glass floors in domestic settings typically use 3-ply laminated toughened glass totalling approximately 33mm (3 x 10mm with 1.52mm PVB interlayers). Higher-traffic retail and assembly floors use 4-ply configurations of around 52–53mm (4 x 12mm with three SGP interlayers). Suppliers step thickness up with span — roughly 25.5mm up to a ~1.0m span, 31.5mm for medium spans and 33mm+ for larger ones — so exact thickness always depends on span, load and support conditions and must be confirmed by structural calculation.

Structural glass typically costs £600-£1,200/m² supply and install depending on application and specification. Walk-on glass floors cost £800-£1,500/m². Glass beams and fins cost more due to specialist fabrication. SentryGlas Plus (SGP) lamination adds approximately 40% over standard PVB.

SGP is a high-performance interlayer for laminated glass that is approximately 100 times stiffer than standard PVB (polyvinyl butyral). It provides much better post-breakage performance and is specified for structural applications where the glass must maintain integrity after one ply breaks, such as overhead glazing and floors.

Yes, structural glass requires full structural calculations by a chartered engineer and Building Regulations approval. In England, walk-on glass must comply with Part A (structure) and Part K (protection from falling, collision and impact) — Part K incorporated the former Part N glazing-safety provisions when Approved Document N was withdrawn in England on 6 April 2013 (Part N still applies in Wales). Safety glazing should be toughened to BS EN 12150 or laminated to BS EN 14449. A specialist structural glass engineer should design the system.

Glass weighs approximately 2.5 kg per m² per mm of thickness. A typical 33mm (3-ply) domestic glass floor panel weighs about 83 kg/m². A 52–53mm (4-ply) retail or assembly floor panel weighs approximately 131 kg/m². Supporting structure must be designed for this dead load plus the imposed (live) load.