Flagship guide · 11 min read
The Complete Guide to Glass Specification
The frame gets most of the attention, but the glass does most of the work. This is our full guide to choosing it properly.
Laminated vs Toughened Glass: Which Do You Need?
Both satisfy Part K, but laminated and toughened glass behave quite differently when broken, and suit different priorities.
3 min read
Toughened and laminated glass are the two types of safety glass recognised under Building Regulations Part K, and either will satisfy the requirement in a critical location. But they are made differently, break differently, and offer different secondary benefits, so the choice between them is worth a moment's thought rather than defaulting automatically to whichever is cheaper.
This guide compares them directly and sets out where each is the better fit.
How each is made
Toughened glass is heat-treated: standard glass is heated to around 620°C and then rapidly cooled, which puts the outer surfaces into compression and the core into tension. This process makes it around five times stronger than standard annealed glass of the same thickness. If it does break, the stored tension causes it to shatter across its entire area into small, blunt granules rather than sharp shards, which is far safer but means the pane is instantly gone.
Laminated glass is built differently: two (or more) panes of glass are bonded together with a tough plastic interlayer, usually PVB, under heat and pressure. It has similar base strength to standard glass, but if it does break, the interlayer holds the fragments in place, so the pane stays substantially intact in its frame rather than falling away.
Side by side
| Toughened | Laminated | |
|---|---|---|
| Strength before breaking | Around 5x standard glass | Similar to standard glass |
| Behaviour when broken | Shatters into small granules across the pane | Stays largely intact, held by the interlayer |
| Security | No advantage — once broken, the opening is clear | Strong advantage — much harder and slower to breach |
| Acoustic performance | No improvement over standard glass | Noticeable improvement, particularly at higher frequencies |
| Typical cost | Lower of the two | Modest premium over toughened |
| Typical use | Shower screens, low-level windows with no security concern | Ground-floor doors and windows, noise-sensitive rooms |
Which to choose
Where the only requirement is Part K compliance and there is no particular security or noise concern — an upper-floor bathroom window, for instance — toughened glass is a straightforward, cost-effective choice. Where the opening is at ground level, faces a road, or sits somewhere security or noise is a genuine consideration — entrance doors, patio doors, ground-floor windows near a boundary — laminated glass is usually worth the modest extra cost for the security and acoustic benefit it brings alongside safety compliance.
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