Tempered vs Laminated Glass: Where Ontario Requires Safety Glass
Tempered and laminated glass are both safety glass under the Canadian standard CAN/CGSB-12.1: tempered is 4–5 times stronger than ordinary glass and breaks into small granular pieces, while laminated cracks but stays bonded to a plastic interlayer. In Ontario homes, safety glass is required in shower and bathtub enclosures, sliding and storm doors, large low panes in entrance doors, and sidelights over 500 mm wide that could be mistaken for a door. When a safety-glass pane breaks, it can usually be replaced glass-only in the existing frame with a tempered or laminated pane made to size.
Tempered glass is 4–5 times stronger than annealed glass of the same thickness and breaks into small, blunt granules; it cannot be cut or drilled after tempering.
Laminated glass bonds two panes to a plastic interlayer, so it cracks in a spider-web pattern but holds together; it also blocks about 88% of UV in window glass.
The Ontario Building Code requires safety glass in shower and tub enclosures, sliding and storm doors, entrance-door glass over 0.5 m² reaching within 900 mm of the floor, and door-like sidelights over 500 mm wide.
Wired glass does not meet either impact class in CAN/CGSB-12.1-2017, and its own safety standard was withdrawn in 2016.
Look for the permanent stamp in a corner of the pane to confirm tempered glass before you order a replacement.
A broken safety-glass pane is replaced on its own, made to size, in the existing door, shower or window frame; the frame stays when it's sound.
On this page
Tempered and laminated glass are both safety glass, but they protect you in opposite ways. Tempered glass is much stronger than ordinary glass and, when it does break, crumbles into small granular pieces. Laminated glass is two sheets bonded to a plastic interlayer, so it cracks but stays in one piece.
Ontario requires one or the other wherever people are likely to walk into glass or fall against it. In a house that means shower and tub enclosures, sliding and storm doors, large low panes in entrance doors, and sidelights that could be mistaken for a door. The rest of this guide covers where the rules apply, how to tell what glass you have, and which type to choose when a broken pane is replaced in your existing frame.
The four glass types compared
| Annealed (ordinary float) | Tempered | Laminated | Wired | |
|---|---|---|---|---|
| How it breaks | Random, jagged shards | Small, similar-sized granular chunks | Spider-web crack; pieces stay bonded to the interlayer | Cracks, held loosely by wire; the wire can worsen cuts |
| Strength | Baseline | 4–5 times annealed of the same thickness; at least 10,000 psi surface compression | Similar to its component panes; the benefit is retention | Actually weaker than unwired glass |
| Counts as safety glass today? | No | Yes, to CAN/CGSB-12.1 | Yes, to CAN/CGSB-12.1 | No; fails both impact classes |
| Cut or drill after making? | Yes | No, it shatters | Yes, with care | Yes |
| Extras | None | Resists thermal stress | Blocks about 88% of UV in window glass; better sound insulation | Still found in older school and institutional doors |
| Relative cost | Lowest | +30–50% over clear | 1.5–2 times clear | n/a |
You may also hear about heat-strengthened glass, which sits between annealed and tempered at 3,500–7,500 psi of surface compression. It's a good choice against thermal stress cracks. Where code calls for safety glass, though, ask for glass marked to CAN/CGSB-12.1 rather than assuming heat-strengthened will do.
The Canadian standard: CAN/CGSB-12.1-2017
Canada's safety glazing standard, CAN/CGSB-12.1-2017, was released on 28 March 2017 and replaced the 1990 edition. It sets two impact classes:
- Class B: a 457 mm drop, 203 J. Every safety glazing product must meet at least this.
- Class A: a 1,219 mm drop, 542 J.
Wired glass meets neither class. Its own standard, CAN/CGSB-12.11, was withdrawn in 2016, and the Canadian Glass Association had already advised in 2015 against using wired glass anywhere people could hit it. The problem was real: Ontario's School Boards' Insurance Exchange recorded over $5.8 million in wired-glass injury claims from 2001 to 2015.
If your older home or building still has wired glass in a door, replacing just that glass with tempered or laminated is a sensible upgrade. The door itself can usually stay.
Where Ontario requires safety glass in homes
The 2024 Ontario Building Code took effect on 1 January 2025. Clause numbers move between editions, but the requirements below are long-standing.
| Location | Requirement |
|---|---|
| Shower and bathtub enclosures | Glass other than safety glass shall not be used for a shower or bathtub enclosure |
| Sliding glass doors within or at entrances | Safety glass |
| Storm doors | Safety glass |
| Entrance-door glass | Safety glass where the glass area exceeds 0.5 m² and extends to less than 900 mm from the bottom of the door |
| Sidelights | Safety glass where the sidelight is wider than 500 mm and could be mistaken for a door |
| Low windows at a drop | A guard is required where the drop exceeds 600 mm; glazing that forms part of a guard needs engineering, not just safety glass |
Shower and bathtub enclosures, storm doors and entrance-door glass are covered twice over: by the Ontario Building Code and by the federal Glass Doors and Enclosures Regulations.
Older code text also still lists wired glass to CAN/CGSB-12.11 as acceptable, even though that standard has since been withdrawn. Don't rely on wired glass where safety glass is required; choose tempered or laminated.
Mirrored doors are another edge case. The BC Building Code, which is based on the national code, allows mirrored glass doors only at clothes closets; confirm the Ontario wording before using a mirror as a door anywhere else. See our custom mirror guide for safety backing options.
The federal product rule
Separately from the building code, the federal Glass Doors and Enclosures Regulations control what can be sold. They cover bathtub and shower doors and enclosures, storm doors, and exterior doors with a glass pane over 0.5 m² whose lowest edge is less than 900 mm from the bottom of the door. That glass must be safety glass, and the responsible party must keep compliance records for at least four years.
For front doors and sidelights specifically, see our entry door and sidelight glass guide.
How to tell if your glass is tempered
Before you order a replacement, confirm what you have. Four checks cover most cases:
- Look for the stamp ("bug") in a corner. It's etched or sandblasted and may read something like "CPSC 16 CFR 1201 CAT II".
- Look through polarized sunglasses. Tempered glass often shows dark bands or spots from the tempering rollers.
- Feel the edges. Tempered edges are smooth because they're finished before tempering.
- Look for faint roller marks on the surface in low-angle light.
Laminated glass is easier to identify: look at an exposed edge and you'll see two sheets of glass with a thin plastic layer between them. In a sealed unit, the stamp on each pane is your best guide.
Which should you choose?
| Situation | Better choice | Why |
|---|---|---|
| Frameless shower door | Tempered, usually 3/8 in (10 mm) | 3/8 in is the standard thickness for frameless doors |
| Patio door sealed unit | Tempered on both panes | Meets the code; consider a laminated pane for security or noise |
| Front door or door-height sidelight | Tempered or laminated | Both comply; laminated holds together after a hit |
| Ground-floor or basement window you worry about | Laminated, or anchored security film on existing glass | A broken laminated pane still blocks the opening |
| Bedroom facing a busy road | Laminated | Better sound insulation |
| Overhead glass, such as a glass canopy | Laminated | Broken pieces stay bonded instead of falling |
| Large south- or west-facing pane | Heat-strengthened or tempered | Resists thermal stress cracks |
For existing glass, security film is the retrofit route. Thicker isn't automatically better: 4 mil film meets ANSI Z97.1, while 8 mil meets ASTM F1233, CPSC Cat II and UL 972, and should be wet-glazed to the frame. Businesses should read after a break-in: board-up and security film.
Replacing tempered glass: what to expect
Because tempered glass can't be cut or drilled once it's made, every replacement is made to order. It must match the original size exactly, and for shower doors, the existing hinge and handle hole pattern too. Tempered shower glass typically takes 7–14 business days to fabricate.
Published GTA prices:
| Item | Range (CAD) |
|---|---|
| Tempered glass pane, replaced | $450–$800+ |
| Laminated safety glass pane, replaced | $500–$900+ |
| Tempering premium on custom-cut glass | +30–50% |
| Laminated vs clear custom-cut glass | 1.5–2 times |
Size, thickness, edgework and holes all change the number.
Spontaneous breakage
Very rarely, tempered glass breaks on its own because of a microscopic nickel sulfide inclusion. It happens only in tempered glass and it is extremely rare; edge damage and frame movement are far more common causes. Heat-soak testing reduces the risk but can't eliminate it. Our article on why tempered shower glass shatters goes deeper.
What we'd do
When you ask us to replace glass in a door, shower or low window, we replace the glass and keep your existing frame where it's sound. We:
- Check the location against the safety-glass rules above, not just what was there before. Older homes sometimes have annealed or wired glass where safety glass is now required.
- Look for the stamp and confirm the type and thickness.
- Measure, including hole positions for shower and hardware-mounted glass, and order the glass tempered or laminated to size for the existing frame.
- Check the frame itself. If it's rotted, cracked or warped, that's a door or window replacement job rather than a glass repair, and we'll tell you if that's where you are.
Next step
If you're not sure whether a pane needs to be safety glass, send us a photo showing where it sits and any stamp in the corner. Start with our window glass replacement page or ask for a free quote through our contact page.