Glazing Thickness Based on Window Size: A Planning Guide

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Glazing thickness is chosen by the width and height of each panel, the wind load on the building, and the type of glass used, not by the outer frame size alone. Larger openings usually need thicker or laminated glass so the panel stays stable and safe. Your engineer or our team confirms the final specification after measuring the actual opening.

Why opening size drives the glass choice

The bigger the glass panel, the more it bends under wind pressure and its own weight. A narrow window can carry thin glass comfortably, while a wide floor-to-ceiling opening needs more thickness to avoid flexing, sealant stress and breakage. Height matters as well, because tall panels catch more wind at upper floors.

Panel dimensions, not the outside size of the frame, are what the glass supplier needs. Two windows of the same overall size can take different glass depending on how many sashes and dividing bars they have.

Measuring the opening correctly

Measurement is done on site, usually with the profile fixed or in its final position. We record the clear width and height of each glass pocket at three points, because walls are rarely perfectly square. Small differences of a few millimetres are noted and planned for.

Check width at top, middle and bottom
Check height at left, centre and right
Note the depth of the glazing channel
Record the floor level and wall material

Matching glass type to the opening

Glass for Belgian steel-look profile windows and doors is selected from tempered, laminated or insulated units depending on use. Tempered glass is stronger and breaks into small pieces, which suits doors and low openings. Laminated glass keeps its layers together when cracked, which is useful at height or near walkways.

Insulated double glazing adds thermal and sound performance but also weight, so the profile and hinges must be sized to carry the heavier unit.

From drawing to production

After measurement we prepare a drawing and a written specification listing each panel, glass type, thickness and profile. You review and approve it before anything is cut. This step prevents costly changes later.

In the factory we cut the steel-look profiles, weld and assemble the frames, and fit the glazing beads. Finishing such as hot-dip galvanizing or powder coating is applied before the glass is set, so the frame is protected from weather.

Installation and checking the fit

On installation day the frame is fixed plumb, level and square, then the glass is set into the pocket with the correct setting blocks and sealant. Gaps are checked for even clearance so the glass can expand and contract without stress.

Checks after installation

Frame is straight and opens without rubbing
Glass sits centred with equal clearance
Seals and beads are tight and clean

Planning for future changes

If you plan to add shading, change the flooring level or install a different window later, mention it at the start. A change in the surrounding structure can alter the load on the glass. Keeping the approved drawing on file makes replacement panels easier to order accurately.

For exact thickness values and compliance with the Israeli railing standard SI 1142 where relevant, the final numbers are checked with the engineer for your building.

Frequently asked questions

Does a bigger window always need thicker glass?

Usually yes, because larger panels flex more under wind and weight. The exact thickness depends on the panel size, height on the building and the glass type, so it is confirmed after measurement.

Can I use the same glass for a door and a window?

Not always. Doors take more knocks and are opened frequently, so tempered glass is often preferred. The right choice depends on the opening and how it is used.

Why do you measure the opening more than once?

Walls are rarely perfectly straight or square. Measuring at several points shows the true clear size so the glass fits without forcing.

Do I need to approve the drawing before production?

Yes. Approving the drawing and written specification before production prevents mistakes and avoids changes to finished parts.

Common mistakes to avoid

Ordering glass from the outer frame size instead of the clear glass pocket is the most common error. Skipping the engineer's check on height and wind exposure can leave a large panel undersized.

Our recommendation

For any opening wider than a standard door, ask for a site measurement before choosing thickness, and consider laminated glass for upper floors or areas near walkways. Keep the signed drawing with your building papers.

Summary

Glass thickness follows the size of each panel, wind exposure and glass type, and is confirmed by measuring the actual opening on site.

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