17.5 mm nominal
Often formed from two 8 mm panes plus a 1.52 mm interlayer; suitability must be verified.
Laminated Balustrade Glass · Overhead Glazing
17.5 · 21.5 · 25.5 MM
Laminated glass for balustrades.
Specified, not guessed.
Toughened laminated glass build-ups from 17.5 mm to 25.5 mm for frameless and supported balustrades, selected against panel size, loading, fixing and exposure.
17.5–25.5 MM
TOUGHENED LAMINATED
Project-specific design
Project-specific cover
Technical support
Supply or installation
Thickness is only one part of the glass specification.
Detail
AT A GLANCE
Key features.
21.5 mm nominal
Often formed from two 10 mm panes plus a 1.52 mm interlayer for higher design demand.
25.5 mm nominal
Often formed from two 12 mm panes plus a 1.52 mm interlayer for more demanding panels or loads.
Interlayer choice
PVB and structural ionoplast behave differently; the selected product must suit the calculation and exposure.
CLEAR DETAILS. EASY CHOICES.
Find what you need.
Product information, installation
and documents in one place.
LAMINATED BALUSTRADE GLASS
Designed for your project.
The familiar 17.5, 21.5 and 25.5 mm descriptions commonly represent two nominal glass plies combined with an interlayer. The finished tolerance and exact build-up are confirmed by the processor and system design.
A thicker laminate is not automatically the right answer. The glass type, interlayer stiffness, panel proportions, edge support, channel, anchors, load category, wind exposure and post-breakage requirement all influence the calculation.
RANGE17.5–25.5 MM
PANESTOUGHENED LAMINATED
INTERLAYERSPVB OR IONOPLAST
SELECTIONPROJECT SPECIFIC
CHOOSE WITH CONFIDENCE
17.5, 21.5 and 25.5 mm glass: what the numbers mean
The rounded trade descriptions 17.5, 21.5 and 25.5 mm commonly refer to nominal 17.52, 21.52 and 25.52 mm laminates. With a 1.52 mm interlayer, the corresponding arrangements are 8 + 1.52 + 8 mm, 10 + 1.52 + 10 mm and 12 + 1.52 + 12 mm. Manufacturing tolerances and the exact glass treatment must be stated in the order.
These are options within the balustrade design process, rather than automatic matches to domestic, commercial or coastal use. Confirm the channel or clamp manufacturer’s accepted build-ups and the design evidence for the actual dimensions and loads.
Toughened glass and laminated glass have different roles
Toughening changes glass strength and breakage behaviour. Lamination bonds panes with an interlayer that retains fragments if the glass breaks. Toughened laminated glass combines these treatments, but the ability of a broken panel to remain an effective barrier depends on the whole assembly.
Heat-soak testing can be specified to reduce the risk associated with nickel sulphide inclusions in toughened glass. It does not eliminate every possible breakage cause or replace the need for a residual safety strategy. Agree pane treatment, safety classification and testing with the designer and processor.
PVB or structural ionoplast for balustrades?
Interlayer performance depends on the specific product, temperature and duration of loading. Conventional PVB and structural ionoplast are not interchangeable descriptions in a structural calculation. Stiffer interlayers can offer design advantages, but the benefits must be verified for the proposed glass and system.
For external and open-edge laminates, assess edge exposure, moisture, drainage and compatibility with sealants and gaskets. Privacy interlayers also need technical selection rather than substitution based only on colour. The final specification should name the exact interlayer product and thickness.
THE COMPLETE SYSTEM
Specification at a glance.
17.5 mm trade description
17.52 mm nominal: 8 mm glass + 1.52 mm interlayer + 8 mm glass
21.5 mm trade description
21.52 mm nominal: 10 mm glass + 1.52 mm interlayer + 10 mm glass
25.5 mm trade description
25.52 mm nominal: 12 mm glass + 1.52 mm interlayer + 12 mm glass
Pane treatment
Toughened laminated options; heat-soak testing where specified
Interlayer
Exact PVB or ionoplast product, thickness and design properties
Verification
Panel size, supports, loads, exposure, retention and post-breakage
Technical guidance is indicative. Final glass, system and fixing design must be confirmed for the site, use category and supporting structure.
YOUR PROJECT. YOUR OPTIONS.
Details for the way you use it.
01
PVB laminate
A widely used safety-glass interlayer with many clear, acoustic and colour options.
02
Structural ionoplast
A stiffer interlayer option that can improve structural and post-breakage performance when correctly designed.
03
Low-iron panes
A clearer appearance, particularly noticeable through thick laminated edges.
04
Heat-soak testing
Can reduce the risk associated with nickel sulphide inclusions in toughened glass; specify where the project risk assessment calls for it.
FROM ENQUIRY TO INSTALLATION
Supply or specialist installation.
Choose a made-to-measure supply package or a coordinated specialist installation. The quotation confirms the design, glass, hardware, fixing and site work included.
01
Share the project
Send approximate run lengths, levels, photographs, plans and the project postcode.
02
Design the system
We review the fixing substrate, drop, loads, exposure, drainage, glass build-up and finish.
03
Approve the details
Coordinated drawings and the agreed specification are confirmed before manufacture.
04
Supply or install
Choose a made-to-measure supply package or a coordinated specialist installation.
Supporting construction, anchors, drainage and finishes are coordinated with your project team.
THE DETAIL, FROM EVERY ANGLE
Laminated Balustrade Glass gallery.
Select a photograph
to look closer.
Coordinated around your edge.
More from our projects
THE COMPLETE BARRIER SYSTEM
Structure first. Glass by design.
The correct glass and hardware cannot be confirmed from appearance alone. We review the complete load path and supporting construction.
DESIGN & SUPPORT
Glass, support and loads.
The complete barrier is assessed for the site, supporting structure and intended use.
Structure first
We review what the balustrade can fix back to.
Glass by design
Thickness follows the loads, panel and support.
One clear package
Made-to-measure supply or specialist installation.
Technical references & content review
Reviewed 1 October 2026. Approved Document K concerns England; requirements elsewhere must be checked separately. Manufacturer references inform system selection and do not represent a claim of partnership or certification for your project.
BEFORE YOU CHOOSE
Useful answers.
Which thickness do I need?+
It cannot be selected safely from height alone. We need the panel dimensions, support condition, system data, barrier load, wind exposure, location and substrate before confirming the build-up.
What is the difference between PVB and ionoplast?+
Both bond glass plies, but structural ionoplast products are substantially stiffer than conventional PVB. The choice affects analysis, edge exposure, post-breakage behaviour, cost and availability.
Is 25.5 mm always safer than 17.5 mm?+
Not by itself. Safety depends on the complete designed system: glass, interlayer, panel size, channel or clamps, anchors and supporting structure.
Can laminated glass be frosted?+
Yes. Privacy can be produced using translucent interlayers, etched surfaces or printed treatments. The visual sample and technical compatibility should be agreed before order.
CUSTOMER FEEDBACK
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LET’S TALK ABOUT YOUR PROJECT
Show us the edge you need to protect.
Send plans, photographs, run lengths, levels and your postcode.
Supply or specialist installation.
We’ll use these details to respond to your enquiry. Privacy policy
Your enquiry goes straight to our team.
PROJECTS & PRACTICAL ADVICE
Details and useful guidance.
THE PROJECT DETAIL
Coordinated around your edge.
Glass · channel or posts · anchors · structure · finishes. We coordinate the architecture and the barrier performance together.
