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What are the standard toughened glass thicknesses and which do I need?

Thursday 20th July, 2017

When it comes to architectural glass, few products are as widely used as toughened glass.

Thanks to its enhanced durability, strength and safety, toughened, or tempered glass has become one of architecture’s most prevalent construction materials.

Toughened glass is around five times stronger than standard annealed glass of the same thickness, is more resistant to scratching and general wear and tear, and the small fragments it crumbles into when broken mean it is also far less hazardous.

As you would expect, the thicker a pane of toughened glass is, the stronger it is. So which thickness do you need to specify when designing your architectural glass feature?

Factors to take into consideration

As the thickness of toughened glass increases, its resistance to impact and pressure increases and it is less likely to bow or warp under stress. But, of course, the thicker the toughened glass is, the heavier and more expensive it becomes, so it’s important to get the balance right and to think carefully about which thickness is optimal for your project.

Toughened glass will generally be used in one of four ways in commercial buildings:

  • Vertically: In glass balustrades, glass doors, glass partitions, glass spandrels, glass panelling/wall coverings and any low-level glazing
  • Overhead: In glass roofs, skylights and glass canopies
  • Furniture: In glass tables (both as glass table tops and as solid glass furniture), glass shelving, display units and retail stands.
  • Underfoot: In glass floors and glass stairs. Typically it is recommended that these be constructed in either laminated or toughened laminated glass.

Any architectural glass that sits either partially or entirely below a threshold of 800mm is required to be some form of safety glass, which will generally be either toughened or laminated glass.

The size of the toughened glass sheet required will also affect the necessary thickness: the bigger the area, the thicker the glass must be.

Toughened glass thicknesses

Toughened glass is readily available from commercial glass suppliers like Peterlee Glass in thicknesses ranging from 5mm to 19mm. In public areas, we would generally advise using 6mm toughened glass as an absolute minimum.

The following table is a rough guide to the range of toughened glass thicknesses required for various common applications. 


Range of recommended thicknesses

Frameless glass balustrades

12mm to 19mm (depending on Uniform Distributed Load)

Glass balustrade infill panels

8mm to 12mm (depending on UDL and span, which can be up to 2000mm)

Glass mullions

19mm (depending on design wind load and mullion height and width)

Glass floors (in toughened laminated glass)

19+12mm to 10+10+10mm (depending on distributed loads, concentrated loads and typical usage)

Glass stair treads (in toughened laminated glass)

10+10+10mm  (assuming a distributed load of 4kN/m² and concentrated load of 4kN)

Overhead glazing

8mm (heat soaking treatment is recommended. Laminated glass should be specified for overhead glazing more than 13m above floor level)

Of course, every project is unique and will have a number of different factors to be considered.

Peterlee Glass’s experienced team of designers and engineers will be able to advise you on specifications for your individual scheme and can guide you through every step of your project, from conception to installation.

Get in touch with the North East’s leading commercial glass suppliers today.

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