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Tempered Shower Glass/Toughened Shower Glass — Cut to Size, Processed to Drawing
Tempering is not an upgrade. But the panel itself is made to your dimensions, and every hole in it is decided before the furnace.
Two statements that sound contradictory and are not. Tempering is a precondition — every shower panel is tempered, and it is not a specification choice you opt into. The glass itself, however, is made to order: cut to your dimensions, drilled to your drawing, edged to your finish. This page sets out what that means for the drawings you send and the decisions you have to make before production starts.
Why the Order Is FixedHeat Soak Testing
What Tempering Actually Does
Tempering is a thermal process. The glass is heated and then cooled rapidly, which puts the surfaces into compression and the core into tension. That internal stress state is what gives tempered glass its two defining properties.
It is stronger
Substantially more resistant to impact and to thermal shock than annealed glass of the same thickness. In a bathroom, that means it copes with the temperature swings of a hot shower against a cold room.
It breaks safely
When it fails, it breaks into small, relatively blunt fragments rather than long shards. This is the reason it is used in showers at all, and it is the property that matters most in the specification.
It cannot be worked afterwards
The same stress state that makes it strong makes it impossible to cut, drill, notch or re-work. Everything has to be finished first. This single fact shapes the entire production sequence.
It is what the product is
Not an upgrade, not an option, not a line item. Shower glass is supplied tempered, and the decorative work is sequenced around that rather than instead of it.
Yet It Is Still Made to Order
Here is where the two statements meet. Tempering is universal; the panel is not.
Shower glass is not bought off a shelf in standard sizes and trimmed to fit on site. Every panel is produced to the dimensions and drawings for that project. Which means that although tempering is not a choice, virtually everything about the panel is:
| | Fixed | Made to your drawing |
|---|
| That it is tempered | Always — a precondition | — |
| Dimensions | — | Cut to size, panel by panel |
| Holes | — | CNC drilled to drawing, for the specific fittings chosen |
| Notches and cut-outs | — | Processed to drawing |
| Edge finish | — | Flat polish, bevel or other finishes |
| Decorative treatment | — | Applied before the furnace, not after |
| Thickness | Follows the configuration | Confirmed for the panel size and use
|
Why this distinction is worth stating. A buyer who reads “tempered” as an optional extra will ask whether it can be omitted to save cost — and the honest answer is no, because the product would not be shower glass. A buyer who reads “tempered” as a standard commodity will assume panels come in fixed sizes — and then discover that a dimension change late in the programme means new panels, not trimmed ones. Neither misunderstanding is expensive to prevent.
Why Fragmentation Matters More in a Bathroom
The way tempered glass fails is the reason it is specified, and the reason is worth being specific about — because a bathroom is not an ordinary room to have glass break in.
Bare feet
A bathroom is the one room where people are routinely unshod. The difference between small blunt fragments and long shards is measured in what happens next.
Wet, hard floors
Tile and stone do not give. A fall in a wet bathroom is a different event from a fall elsewhere, and breakage is one of its causes.
Enclosed space
A shower enclosure is a small volume with hard surfaces on every side. There is nowhere to move to.
It happens without warning
Impact breakage is at least preceded by an impact. Spontaneous breakage is not — which is why the heat soak option exists at all.
This is also why tempering is described throughout this site as a precondition rather than a preference. It is not a claim about product quality; it is a statement about what the product has to be.
One step further.Tempering governs how the pane breaks. Whether it stays in the opening afterwards is a separate property, and a separate decision —see laminated vs tempered shower glass.
Measuring for Made-to-Order Panels
Because panels are cut to size rather than trimmed on site, the measurement is the specification — and this is where most made-to-order problems begin.
Openings Are Rarely Square
A drawing will show a right angle. The building will provide something close to one. In a single-panel alcove that difference is usually absorbed by the fixing method; in a corner unit it is not, because two walls have to be vertical and square to each other, and the tolerances add up. That is set out on the corner page, and it is worth reading before the panels are ordered rather than after.
What to Measure
| Width at more than one height | Walls bow and lean. A single measurement across the top will not tell you what is happening at the bottom |
| Height at more than one point | Floors are rarely level, and a shower tray or base introduces its own falls |
| Diagonals on corner units | If the two diagonals of the opening differ, the corner is not square. Both legs need measuring separately |
| What the panel has to clear | Skirting, tile trims, tray upstands and fixtures all reduce the usable dimension |
| Whether the tray or base is in place | Measuring before it is fitted is measuring a different opening |
Shaped Panels
Not every panel is a rectangle. Shaped corners, angled cuts and cut-outs for obstacles are all machined at the same stage as everything else — before the furnace, with the same consequence. A shape that is wrong is a new panel, not a trimmed one.
The useful habit. Measure the opening twice, at different points, after the tray and tiling are in — and send the drawing rather than a list of numbers. A drawing shows the out-of-square; a list of six dimensions does not.
Why the Order Is Fixed
One rule governs everything on this page, and every other page on this site depends on it.
Nothing can be done to glass after it has been tempered. Not drilled, not cut, not notched, not re-worked in any way. Attempting it does not damage the glass — it destroys it, which is rather the point.
So the sequence is fixed by physics rather than by preference:
| Stage | What happens | What has to be decided by then |
|---|
| 1. Cutting | Glass is cut to the panel dimensions | Final panel sizes |
| 2. Drilling and notching | Holes, notches and cut-outs are machined | The fitting selection — hole diameter, position and edge distance all follow the hinge or clamp chosen |
| 3. Edge work | Edges are polished, bevelled or otherwise finished | Edge finish, and whether the edge will be visible |
| 4. Decorative processing | Printing, etching or coating is applied | Artwork sign-off — because the furnace is what fixes the ink |
| 5. Tempering | The panel goes into the furnace | Everything. After this, no changes are possible
|
The consequence that costs money. A dimension change, a fitting change or an artwork change after tempering does not produce a reworked panel — it produces a new one, at the full cost, and one that has already passed through the most expensive stage of the process. This is why the drawing matters more than the deadline, and why the two questions worth answering early are: are the panel dimensions final, and is the fitting selection final?
The same rule is what sits behind the hole-pattern constraint on the hinged and hardware pages. This is the page where the rule itself is explained; those pages show what it costs when it is forgotten.
Thickness: Follows the Panel, Not Preference
Thickness is not freely chosen. It is determined by the application — and getting it wrong is not a matter of preference.
| What determines it | Panel dimensions, whether the panel is fixed or forms part of a moving door, the support method, and the hardware it carries |
| Frameless | 10 mm / 12 mm |
| Semi-frameless | 8 mm / 10 mm |
| Framed | 6 mm / 8 mm |
| Why frameless is thicker | With no frame, the glass is the structure. The panel carries its own loads, and the fittings carry the panel |
One operational point: a project that mixes thicknesses is specifying two different products. An 8 mm fixed panel with a 10 mm door is a legitimate specification, but each has to be produced and checked separately — and where a body tint is used, the two will not read as the same colour. Details are on the frameless page.
Heat Soak Testing
This is the part of the process that most buyers never hear about, and it addresses the one failure mode that tempering cannot prevent.
The Problem It Addresses
Tempered glass can, occasionally and without warning, break on its own. It is rare, it is not caused by impact, and it is not a manufacturing defect in the ordinary sense.
The usual cause is a microscopic nickel sulphide inclusion — a contaminant measured in fractions of a millimetre, introduced during glass manufacture. Over months or years, the inclusion can change state and expand slightly. Inside the stressed core of a tempered panel, that expansion is enough to initiate a break.
The result is a panel that has been installed, signed off and possibly in service for a year, and then fails without anyone touching it.
What Heat Soak Does
Heat soak testing is a destructive test carried out after tempering. Finished panels are loaded into a furnace and held at an elevated temperature for a sustained period, under conditions governed by the applicable standard.
The purpose is deliberately simple: if a panel contains a critical inclusion, make it break in the furnace rather than in a finished bathroom. Panels that survive the cycle are the ones that ship.
Be precise about what it does and does not do. Heat soak testing substantially reduces the likelihood of spontaneous breakage in service. It does not eliminate it, and no test can. A supplier who promises zero spontaneous breakage is promising something the physics does not support — and a buyer who believes that promise will be badly served by it.
When It Is Worth Specifying
Where replacement is disruptive
A panel above a tiled floor in an occupied hotel room costs far more to replace than the panel. The disruption, not the glass, is the expense.
Where failure is a safety exposure
Care settings, assisted-use bathrooms, anywhere a sudden failure has consequences beyond inconvenience.
Programmes rather than one-offs
Across hundreds of units, a low individual probability becomes a near-certainty somewhere in the estate. Programmes specify it; single bathrooms often do not.
Where the contract requires it
Some specifications simply mandate it. Where they do, say so at enquiry rather than discovering it at production.
It is carried out where specified. It is available on request, and it is not presented as standard on every panel — partly because not every application needs it, and partly because presenting it as universal would be an over-claim.
Parameters — temperature, soak duration and the standard applied — follow the applicable standard for the destination market and are confirmed for each order. No figures are published here, because a number printed on a page is either wrong for your market or wrong for someone else's.
This Is the Rule the Rest of the Site Runs On
One reason this page exists: the rule explained here is the constraint that many other pages refer to without explaining. Knowing where to look for it saves a buyer from assembling it piecemeal.
| Where the rule appears | What it means there |
|---|
| Hardware | The hole pattern is machined before tempering, so the fitting selection is a glass specification rather than an accessory choice — see hardware |
| Hinged doors | Hinge holes, edge distances and cut-outs are fixed before the panel is made; changing hinge afterwards means a new panel — see hinged |
| Corner units | Two walls each contribute tolerance, and the panels are cut to suit the opening as built — see corner |
| Printing | Ceramic ink is fused into the glass by the furnace. The furnace is the process, not a later step — see printed glass |
| Etching | Etching happens before tempering, then the panel is tempered regardless — see etched glass |
| Patterns | Rolled patterns are chosen from existing ranges partly because a new one cannot be substituted after the fact — see custom patterns |
Every one of those constraints is the same constraint. This is the page where it is stated in full.
Safety Glazing Requirements
What can be said plainly, and what cannot.
Shower glass is supplied tempered. Applicable safety glazing requirements for the destination market are discussed and agreed before production, because they differ by country and by application.
That is the full extent of what this page claims, and it is deliberate. Specific standard designations, test methods and certification marks are confirmed for the destination market at the time of order rather than asserted here — because a claim that is wrong in one jurisdiction is worse than no claim at all, and because the buyer's own compliance obligation is not discharged by a statement on a supplier's website.
Ask this at enquiry. Two questions, both worth asking early: which safety glazing requirements apply in the destination market, and what documentation is needed with the shipment? Both are easier to answer before production than after it, and both affect what has to be planned for rather than what can be added at the end.
What a Made-to-Order Enquiry Needs
None of this is obligatory, and each item removes a round of questions.
Panel dimensions
Width and height per panel, and whether any are out of square. This is the starting point for everything else.
Configuration
Hinged, sliding, bifold or walk-in — because it sets the thickness range and determines which fittings are needed. See enclosure systems.
Fitting selection
Hinges, clamps or rollers, identified as far as possible. Their hole pattern is machined before tempering — see hardware.
Holes, notches and edge finish
Marked on a drawing. If the fitting is known, the pattern usually follows from it.
Glass type
Clear, low-iron, or one of the decorative types on the decorative glass pages.
Whether heat soak is required
Specified at enquiry. Adding it after production is not possible — the test is part of the sequence, not an inspection afterwards.
Destination market
Determines which safety glazing requirements apply and what documentation ships with the order.
Quantity
Including whether repeat orders are expected, since the approved drawing is what they are checked against.
Technical Specifications
| Glass type | Tempered safety glass. Laminated construction where the application requires it |
| Dimensions | Cut to size, made to order — produced to project drawings, not supplied in standard sizes |
| Thickness | 6 mm / 8 mm / 10 mm / 12 mm, subject to panel size, configuration and market requirements |
| Processing sequence | Cutting → drilling and notching → edge work → decorative processing → tempering |
| After tempering | Nothing. Cannot be drilled, cut, notched or re-worked |
| Holes and notches | CNC processed to drawing, from the selected fittings' hole pattern |
| Edge | Flat polish, bevel and other edge finishes |
| Decorative processing | Printing and etching are applied before tempering, never after — see printed and etched |
| Heat soak testing | Available where specified. Carried out after tempering, to the applicable standard for the destination market, parameters confirmed per order |
| What heat soak does | Substantially reduces the likelihood of spontaneous breakage from nickel sulphide inclusions. Does not eliminate it — no test does |
| Safety glazing | Applicable requirements for the destination market agreed before production. No specific standard is asserted here |
| Packaging | Export packaging configured for glass panels |
See what can be developed and what can only be selected →
Request Tempered Shower Glass
Send the dimensions and the configuration if you have them. If you do not, send what you have and we will work through it.
Name
Business email
Company
Configuration
Please select…
Frameless
Semi-frameless
Framed
Hinged
Sliding
Bifold
Walk-in
Panels only — no enclosure
Not decided — please advise
Sets the thickness range and which fittings are needed.
Panel dimensions
Glass thickness
Please select…
6 mm
8 mm
10 mm
12 mm
Not decided — please advise
Follows the configuration and panel size.
Glass type
Please select…
Clear
Low-iron
Fluted
Reeded
Textured
Frosted or etched
Tinted
Printed
Back painted
Not decided — please advise
Is heat soak testing required?
Please select…
Yes — please include it
No — not required
Not sure — please advise
Specified at enquiry. It cannot be added after tempering.
Fitting selection final?
Please select…
Yes — fittings confirmed
Partly — some confirmed
No — not yet chosen
No fittings — fixed panels only
Hole patterns are machined before tempering, from the fittings chosen.
Quantity
Destination country
Determines which safety glazing requirements apply.
Drawing upload (optional)
PDF, DWG, DXF, SKP, JPG or PNG.
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Everything Has to Be Decided Before the Furnace
Dimensions, holes, notches, edges and artwork — all of it is finished before tempering, because none of it can be changed after. The earlier the drawing is final, the cheaper the order is.
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