Thickness by use
What thickness glass do I need?
Choose what the glass is for and read the thickness the workshop would cut, whether it is toughened, and why. Then open the configurator with that thickness already set.
The link reopens the chooser on the same use.
The whole table
Typical glass thickness by use
Trade-standard picks by use, the same table the chooser above applies. The thickness is what the workshop would cut for that job without being told otherwise; the reason is why. Balustrades, floors, overhead glazing and anything load-bearing need a site-specific design check on top.
| Use | Typical thickness | Toughened | Why |
|---|---|---|---|
| Glass shelf | 6mm to 500mm span, 8mm to 800mm, 10mm beyond | Yes | A shelf is a beam. Sag grows with the cube of the span and shrinks with the cube of the thickness, so the span between brackets decides it, and toughened so a knock does not leave shards on the shelf below. |
| Full table top | 10mm | Yes | A full top takes elbows, dropped plates and hot dishes across a wide unsupported face; 10mm toughened stays flat and takes the heat and the knocks. |
| Table protector | 6mm | Yes | It sits on a solid top, so it does not have to span anything; it only has to resist scratches and heat, which 6mm toughened does. |
| Splashback | 6mm | Yes | The hob throws heat at it, so it is toughened for thermal shock; 6mm is thick enough to polish an edge on and thin enough to sit behind a worktop upstand. |
| Shower screen | 8mm | Yes | A frameless panel is held on hinges and clamps at a few points, so it needs the stiffness of 8mm or 10mm; toughened is required by BS EN 14428. |
| Balustrade | 10mm | Yes | A barrier holds people back, so this is a containment case under BS 6180 and Approved Document K, not a thickness guess; 10mm toughened is the floor and laminated toughened is the usual specification. |
| Mirror | 4mm up to a metre, 6mm over | Not required by thickness; check the position | Thin mirror bows on a large face and the reflection swims; 4mm is fine up to about a metre, 6mm keeps a large or frameless mirror flat. |
| Greenhouse | 4mm | Yes | Horticultural glass is 3mm and cheap, but it breaks into shards over the beds; 4mm toughened survives hail and breaks safely if it goes. |
| Picture frame | 4mm | Not required by thickness; check the position | Framing glass is 2mm because a frame's rebate is shallow and the weight matters on a wall hook; we do not cut 2mm online, and 4mm float suits large or box frames. |
| Frameless internal door | 10mm | Yes | A frameless door hangs from patch fittings at its corners and is walked into; 10mm toughened is the trade standard for rigidity and for Approved Document K. |
| Small single-glazed pane | 4mm | Not required by thickness; check the position | A small single-glazed pane in a frame is supported on all four edges, so 4mm float is enough structurally; whether it must be safety glass depends on where it sits, which the safety checker decides. |
Shelf spans are the one case where the number moves with the size: the shelf load calculator shows the load and the sag for your exact span. Whether a position legally needs safety glass is the safety glass check.
Straight answers
Thickness questions
Are these thicknesses a structural calculation?
No. They are the trade-standard picks the workshop cuts by default for each use, with the reason stated. Shelves get a real check on the shelf load calculator; balustrades, floors, overhead glazing and anything load-bearing need a site-specific design check by an engineer.
How thick should a glass shelf be?
It depends on the span between the brackets: 6mm toughened up to 500mm, 8mm to 800mm, 10mm beyond. Sag grows with the cube of the span and shrinks with the cube of the thickness, so a shelf that is fine at 500mm can visibly bow at 800mm in the same glass.
Does thicker glass mean safer glass?
Not on its own. Safety glass is glass that breaks safely, which is toughening or laminating, not thickness. Approved Document K does allow thick annealed glass in some critical locations within size limits, but the usual answer in a door, a low window or a bathroom is toughened glass of the thickness the use needs.
Why 6mm for a splashback and 10mm for a table?
A splashback is bonded flat to a wall, so it spans nothing and only has to take heat and cleaning; 6mm toughened does that and still polishes to a clean edge. A table top spans its whole width unsupported and takes knocks, so it needs the stiffness of 10mm.