6.38mm Vs 8.38mm Laminated Glass: The Best 2026 Guide

6.38mm vs 8.38mm laminated glass — here is what South African buyers need to know, with supply, installation and service from Coetz Glazing.

6.38 mm and 8.38 mm laminated glass are both safety glass: two panes bonded to a tough PVB interlayer that holds the glass together if it breaks. The difference is thickness and the strength, sound insulation and rigidity that come with it. Coetz™ supplies both, cut to size — here’s when to choose each.

Quick comparison

Feature	6.38 mm Laminated	8.38 mm Laminated
Construction	2 × 3 mm + 0.38 mm PVB	2 × 4 mm + 0.38 mm PVB
Strength	Strong — the everyday standard	Stronger — for larger/heavier panes
Sound reduction	Good	Better — more mass
Rigidity	Suits most windows and doors	Less flex on large panes
Weight	Lighter	Heavier
Cost	More economical	Higher
Best for	Standard windows and doors	Large panes, noise, added strength

Construction & strength

6.38 mm laminated is built from two 3 mm panes bonded to a 0.38 mm PVB interlayer — the everyday safety-glass standard used across most windows and doors. 8.38 mm steps the panes up to 4 mm each, adding strength and rigidity that helps larger or more exposed panes resist flexing and impact.

Acoustic & security benefits

Extra mass means 8.38 mm laminated dampens sound better than 6.38 mm — worth considering near busy roads or for quieter bedrooms. Both are laminated, so both hold together when broken and resist penetration; the thicker build simply adds more resistance, which can be useful where extra security is wanted.

When to step up to 8.38 mm

For most standard-size windows and doors, 6.38 mm laminated is the right, cost-effective choice. Consider 8.38 mm for large glass panels, particularly exposed or high-traffic openings, noise-sensitive rooms, or where you simply want extra strength and peace of mind. If you’re unsure, we’ll help you specify the right thickness for the pane size and application.

Advantages of 6.38 mm laminated

The proven everyday safety-glass standard
Lighter and more economical
Suits most standard windows and doors
Holds together when broken (PVB interlayer)
Coetz™’s standard door glazing

Advantages of 8.38 mm laminated

Greater strength and rigidity
Better sound reduction
Ideal for large or exposed panes
Added security resistance
Less flex on big glass areas

6.38mm vs 8.38mm laminated glass: what the numbers mean

The figures describe the make-up of the pane, not a grade or a quality rating. A laminated pane is two sheets of glass bonded to an interlayer, and the number is the total nominal thickness of that sandwich. So the 6.38mm vs 8.38mm laminated glass comparison is a comparison of build-up rather than of quality — both are laminated safety glass, and both behave the same way when broken.

That shared behaviour is the point of laminating. The interlayer holds the fragments together instead of letting the pane fall out of the frame, which is why laminated glass is the sensible default in a home. Choosing between 6.38mm vs 8.38mm laminated glass is therefore a question of how much glass you need, not whether it is safe.

6.38mm vs 8.38mm laminated glass: mass and handling

The most immediate practical difference is weight. A thicker pane is a heavier pane, and that carries through the whole assembly: heavier sashes, more load on hinges, rollers and tracks, and more effort to move a large opening leaf.

On a small window the difference is negligible. On a large sliding or folding door it is not, and it is one of the reasons the 6.38mm vs 8.38mm laminated glass decision should be made alongside the frame and hardware rather than in isolation. Tell us the pane sizes you have in mind and we will confirm what is appropriate for the configuration.

6.38mm vs 8.38mm laminated glass: acoustic considerations

Mass and damping both matter to sound, and a thicker laminated build-up generally performs better acoustically than a thinner one of the same type. How much better depends on the frequency, the frame, the seals and the installation, so it is not a figure that can be quoted meaningfully in the abstract.

If noise is the reason you are weighing 6.38mm vs 8.38mm laminated glass — a bedroom facing a busy road, an office near a taxi rank — say so when you enquire and describe the noise source. That is far more useful than a specification asked for in isolation, because the frame and seals often matter as much as the glass.

6.38mm vs 8.38mm laminated glass: cost

More glass and more interlayer cost more per square metre, and the difference compounds across a whole house. On a single large pane the step up is modest; across every opening in a new build it is a real line item.

The practical approach most projects take is not to choose one thickness for everything. Specify the standard build-up generally, and step up only in the specific locations where there is a reason to — which is usually a better use of budget than applying the heavier specification everywhere.

Where the heavier specification is typically considered

Large single panes. As pane size grows, the case for more glass grows with it.
Noise-exposed elevations. Rooms facing traffic, schools, or busy commercial frontage.
Ground-floor and street-facing openings where the additional mass is wanted.
Exposed sites — coastal, elevated or high-wind locations, where the wind loading on the pane is greater.
Where a specifier has called for it. If an architect, engineer or estate has specified a thickness, that specification governs.

Outside those situations, the 6.38mm vs 8.38mm laminated glass question usually resolves in favour of the standard build-up, which is what the large majority of residential openings are glazed with.

How to decide for your own project

The decision is easier when it is framed as a series of questions rather than as a single comparison.

How big is the pane? Size is the first driver, and it interacts with everything else.
Where is it? Ground floor or upper, sheltered or exposed, quiet or noisy.
What is the frame and configuration? A fixed pane, an opening sash and a sliding leaf all carry glass differently.
Has anyone specified a thickness? An architect’s or engineer’s specification, or an estate requirement, settles the matter.
What is the budget across the whole project? Selective use of the heavier build-up is usually better value than blanket use.

Send those answers with your opening sizes and we will confirm what is appropriate. Where a project requires a specific thickness or a performance figure, that determination belongs with the project’s design team — this page is general guidance and not a compliance opinion or a substitute for professional advice.

What laminated glass does when it breaks

This is the property that matters most, and it is shared by both build-ups. When a laminated pane is broken, the interlayer holds the fragments in place rather than letting them fall. The glass cracks but generally stays in the opening.

That behaviour is why laminated glass is specified in homes with children, at ground-floor level, and anywhere a falling pane would be a hazard. It is also why the 6.38mm vs 8.38mm laminated glass choice is not a safety trade-off — you are not buying more safety by going thicker, you are buying more glass.

It is worth being clear about the limit of that claim. Laminated glass is not unbreakable, and no glass specification should be relied on as a security measure on its own. Locking, framing and how the pane is fixed all matter.

Laminated versus toughened: a different question entirely

People often arrive at the 6.38mm vs 8.38mm laminated glass comparison when the question they actually have is laminated versus toughened. These are different things.

Laminated is two sheets bonded to an interlayer. Broken, it holds together in the frame.
Toughened is heat-treated for strength. Broken, it shatters into small, relatively blunt pieces rather than large shards.

Both are safety glass and both have their place; they simply fail differently. Our guide to laminated versus toughened safety glass sets out the comparison properly. Resolve that question first, because it determines the product, and only then weigh 6.38mm vs 8.38mm laminated glass, which determines the build-up within it.

Ordering glass cut to size

If you are replacing a pane rather than buying a complete window, the thickness question comes up in a slightly different form: you have to match what is already in the frame.

Measure the glass, not the opening, if you are replacing a pane in an existing frame — and measure the rebate depth too.
Check what is currently fitted. Laminated panes usually carry an edge mark. Matching the existing build-up avoids beading and fitting problems.
Confirm the frame can take it. A frame glazed for a thinner pane may not accept a heavier one without changing the beading.
Order square, and allow the clearance the glazier needs to seat the pane.

Our Coetz™ Cuts to Size calculator lets you enter dimensions and request a quotation directly. If you are unsure which build-up you have, send a photograph of the edge mark and the frame section rather than guessing at 6.38mm vs 8.38mm laminated glass.

Common misconceptions about glass thickness

A few assumptions come up repeatedly, and each one leads to money spent in the wrong place.

“Thicker glass is safer glass.” Not in the way people mean. Both options in the 6.38mm vs 8.38mm laminated glass comparison are laminated safety glass and both hold together when broken. Thickness buys mass, not a different failure mode.
“Thicker glass is burglar-proof.” No glass specification should be treated as a security system. Locking, framing and how the pane is fixed into the frame matter at least as much.
“Thicker glass fixes draughts.” Draughts are a seal and installation problem, not a glass problem. Stepping up the build-up will not correct a poorly sealed frame.
“I should use the thickest available everywhere.” That loads the hardware unnecessarily and spends budget that would do more good elsewhere in the build.
“The supplier will just know.” We can advise, but only against the information you give us — pane sizes, elevation, configuration and what you are trying to solve.

Approached properly, 6.38mm vs 8.38mm laminated glass is a straightforward decision made once per opening type rather than agonised over pane by pane. The standard build-up covers most situations, and the step up is a deliberate, located choice.

What to send us with your enquiry

Pane or opening sizes in millimetres, width first.
Which elevation each opening faces, and whether the site is exposed or coastal.
The configuration — fixed, opening sash, sliding or folding leaf.
Any specification already issued by an architect, engineer or estate, which settles the question.
What you are trying to solve, if anything — noise, an unusually large pane, or a specific requirement.

With those in hand we can confirm the build-up rather than leaving you to weigh 6.38mm vs 8.38mm laminated glass without the information that actually decides it. This page is general guidance and not a compliance opinion or a substitute for professional advice.

6.38mm vs 8.38mm laminated glass: the short answer

For most residential windows and doors, 6.38 mm clear laminated safety glass is the Coetz™ standard and is what the majority of openings are glazed with. Step up where the pane is unusually large, where noise is the reason for the specification, or where a designer has called for it.

If you are still unsure after weighing 6.38mm vs 8.38mm laminated glass, send the opening sizes, the elevation they face and a note on what you are trying to solve. That is enough for us to advise on the right build-up rather than leaving you to guess at a number.

Which should you choose?

Best for standard windows and doors: 6.38 mm.
Best for large glass panels: 8.38 mm.
Best for noise reduction: 8.38 mm.
Best value for most homes: 6.38 mm.
Best for extra strength and security: 8.38 mm.

Coetz™ cuts both 6.38 mm and 8.38 mm laminated glass to your exact size. Send us your pane sizes and application for a no-obligation quotation.

Is 8.38 mm laminated glass stronger than 6.38 mm?

u003cpu003eYes. 8.38 mm uses thicker 4 mm panes versus 3 mm, giving more strength, rigidity and better sound reduction. Both are laminated safety glass that holds together when broken.u003c/pu003e

Which laminated glass does Coetz™ use as standard?

u003cpu003e6.38 mm Clear Laminated Safety Glass is Coetz™’s standard door glazing and suits most standard windows and doors. Thicker 8.38 mm is available where more strength or sound reduction is wanted.u003c/pu003e

Does thicker glass reduce noise?

u003cpu003eYes, to a degree. The extra mass of 8.38 mm laminated dampens sound better than 6.38 mm, which can help in noisy locations. For serious acoustic needs, specialist acoustic laminates are also available.u003c/pu003e

When should I choose 8.38 mm over 6.38 mm?

u003cpu003eConsider 8.38 mm for large glass panels, exposed or high-traffic openings, noise-sensitive rooms, or where you want extra strength. For most standard openings, 6.38 mm is the right, economical choice.u003c/pu003e

Is 8.38 mm laminated glass safer than 6.38 mm?

No. Both are laminated safety glass and both hold together in the frame when broken, because both have an interlayer. The 6.38mm vs 8.38mm laminated glass difference is thickness and mass, not safety behaviour.

When should I specify the thicker build-up?

Typically for unusually large panes, noise-exposed elevations, exposed or high-wind sites, or where an architect, engineer or estate has specified it. Outside those situations most residential openings are glazed with the standard build-up.

Does thicker glass make a window quieter?

Generally a thicker laminated build-up performs better acoustically than a thinner one of the same type, but how much better depends on the noise source, the frame, the seals and the installation. Describe the noise problem when you enquire rather than specifying a thickness in isolation.

Does the thicker option affect the frame or hardware?

Yes. A thicker pane is heavier, which loads sashes, hinges, rollers and tracks more. On large sliding or folding doors this matters, which is why the 6.38mm vs 8.38mm laminated glass decision should be taken alongside the frame and configuration.

Can I mix thicknesses across one project?

Yes, and most projects do. Specifying the standard build-up generally and stepping up only where there is a reason is usually better value than applying the heavier specification to every opening.

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Glass Cut to Size

6.38 mm and 8.38 mm laminated glass cut to your exact size.