Glass Thickness for Railings: How to Read the Specification

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Glass thickness for a railing is written as a combination of nominal thickness, glass type (tempered or laminated) and interlayer. Reading these correctly tells you how the panel is built and how it will behave in use. Exact load values should always be confirmed with your engineer.

What the Thickness Figure Actually Means

A specification such as 10.76 mm laminated or 12 mm tempered is more than a single number. The nominal thickness is the glass itself, while laminated panels add one or more plastic interlayers bonded between sheets. The total is often written as the sum of the glass layers and the interlayer, for example 6+6 with a 0.76 mm PVB layer.

Always check whether the figure refers to the finished unit or to the raw glass before cutting, because small differences change the fit in the channel or clamp.

Tempered vs. Laminated Glass

Tempered glass is heat-treated to resist breakage and breaks into small, blunt pieces. Laminated glass holds together when cracked because the interlayer keeps fragments bonded. Most railings for homes and balconies use laminated glass for this reason.

Tempered: stronger per millimeter, safer if broken
Laminated: stays in place after impact, suited to balconies and stairs
Ask which type is quoted for each panel

Reading the Drawing Notes

A good drawing will name the glass type, nominal thickness, interlayer, edge finish and the fixing method. Look for the panel height, the span between posts, and whether the glass is clamped, channel-set or fixed with point fittings. Each fixing method affects how the thickness is interpreted.

If any of these items is missing from your written specification, ask for it before you approve the order.

Height, Span and Fixing

Glass thickness cannot be judged alone. A taller panel or a wider span between supports needs a different build than a short, narrow one. The fixing system also changes how load moves through the glass into the structure.

Standing railings should be checked against the Israeli railing standard SI 1142 in general terms, and the specific minimum values for your project should be confirmed with the structural engineer who signs the design.

Questions to Ask Before Approving

Before you sign off on a specification, confirm the details in writing. This keeps the installation predictable and avoids rework on site.

What glass type and total build-up is proposed?
What is the panel height and maximum span?
Which fixing method is used, and does it match the structure?
Has the engineer reviewed the design?

Measuring and Confirming on Site

Our process starts with an inquiry and photos, followed by an on-site measurement. The measurements, drawing and written specification are then sent for your approval before anything goes into production. This sequence lets you compare the glass build with the real opening rather than with assumptions.

Keep a copy of the approved specification, since it becomes the reference for finishing and installation.

Frequently asked questions

Is laminated glass always required for railings?

Not always, but it is common for balconies, stairs and areas where people lean. Your engineer and the project requirements determine the right choice for each location.

What does 6+6 mean on a glass spec?

It usually means two 6 mm glass layers bonded together, typically with an interlayer. The exact interlayer thickness should be stated on the drawing.

Can I use the thickness from one project on another?

No. Height, span, fixing method and location all affect the required build, so each project needs its own confirmed specification.

Who confirms the final glass thickness?

The final build should be confirmed with the structural engineer and approved by you on the written specification before production.

Common mistakes to avoid

Approving a glass thickness without checking the glass type, height, span and fixing method together is the most common error. Always read the full specification, not just the millimeter figure.

Our recommendation

Request a written spec that lists glass type, build-up, interlayer, panel height, span and fixing, then have the engineer confirm it before production starts.

Summary

Glass thickness for a railing only makes sense alongside glass type, interlayer, height, span and fixing method. Read the full specification and confirm the details in writing before you approve.

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