Service

Structural glazing

Structural glazing carries load through the glass itself rather than through a surrounding frame. The glass is held on bolted spider fittings, glass fins or structural silicone, giving an uninterrupted glazed surface with no visible framing.

Free measured survey · fixed written quotation

Structural glazing — technical detail
Structural glazing — technical detail
  • Free measured site survey
  • Fixed written quotation
  • Mainland UK coverage
  • Commercial specialists only
  • 24-hour emergency response

Every structural glazing job is an engineering job first

There is no catalogue item here. Pane size, wind exposure, fixing centres and the deflection of whatever the glass is fixed to all feed a calculation before anything is ordered. Get it wrong and the glass does not simply look poor — it fails.

We produce load calculations and fixing details for approval before manufacture, and the glass is heat soaked to BS EN 14179 to reduce the risk of spontaneous nickel sulphide failure. On a bolted facade that is not a nicety; it is the difference between a 40-year facade and an incident.

Spider fittings, fins or structural silicone

Bolted spider fittings give the classic frameless look and allow the glass to be supported back to a steel or a glass fin. They demand drilled and toughened glass, which fixes the design early because a drilled pane cannot be altered afterwards.

Glass fins remove the steel entirely and give a fully transparent wall, at a significant cost premium. Structural silicone glazing bonds the glass to a hidden frame — cheaper, faster and visually close, but the frame is still there behind the joint line.

Thermal movement and the joints between panes

Frameless glazing lives or dies on its joints. A 12m run of glass moves several millimetres between a January night and an August afternoon, and that movement has to go somewhere.

Silicone weather joints are sized for the calculated movement, not chosen by eye, and the fixings are detailed to allow rotation at the bolt. Rigidly clamping a structural pane at every corner is the most common cause of edge damage on this kind of facade.

Specification

Specification
Glass build-upTypically 10.10.4 or 12.12.4 laminated toughened, heat soaked
Heat soakBS EN 14179 — mandatory for overhead and structural applications
Fittings316 stainless spider arms, countersunk or button bolts
Fin depth200mm–600mm depending on span and wind load
Load designBS EN 1991-1-4 wind loading, deflection limited to span/200
SiliconeStructural silicone to ETAG 002 where SSG is used
Maximum single paneUp to 3.2m × 12m subject to handling and access
Typical lead time8–14 weeks — every pane is bespoke

Indicative rate

£700 – £1,400
per m² · excludes VAT

Supply, engineering and install. Feature entrances, oversized panes, structural steel and difficult access sit above this band and are priced individually.

Indicative range for budgeting — not a quotation

Build a budget figure Book a free survey

Structural glazing — common questions

Is structural glazing safe in a fire or an impact?
The glass is laminated so that a broken pane holds together on its interlayer rather than clearing the opening. Structural glazing is not fire-rated in itself — where a fire rating is needed the specification changes to a tested fire-rated system.
How much more does frameless glazing cost than curtain walling?
Broadly double, sometimes more. A stick curtain wall sits in the £550–£850/m² band; frameless structural glazing typically starts around £700/m² and rises steeply with pane size, fin work and access.
What happens if one pane gets damaged?
It is replaced individually, but the lead time is the same 8–14 weeks as the original because the pane is bespoke, toughened, drilled and heat soaked. On critical elevations clients often hold a spare pane in store for exactly this reason.
Can existing glazing be converted to frameless?
Only as a full replacement. The loads move from the frame into the glass and its fixings, so the supporting structure almost always needs review and often needs strengthening. It is a new facade, not a modification.
Why does structural glass have to be heat soaked?
Toughened glass can contain microscopic nickel sulphide inclusions that expand over years and shatter the pane without warning. Heat soaking to BS EN 14179 forces those failures in the factory, cutting the in-service risk to a small fraction of what it was.

Tell us what the building needs

Free measured survey, fixed written quotation, and a straight answer about what is and is not worth doing. Mainland UK, commercial work only.