Glass balustrades for light, open stairs and balconies

Glass on a stair, landing or balcony keeps the room light and the view open.

It still has to stop people falling. The safest designs keep doing that even if a panel cracks.

These notes help you choose a glass balustrade that keeps the light and does its job for years. They cover the type of glass, the way it is held, how it is looked after, and the building rules.

Choosing the glass

Toughened glass is called safety glass because it breaks into pieces that are less likely to cut. That label is about injury from the breaking itself. It says nothing about a fall through the gap left behind.

The Standing Committee on Structural Safety (SCOSS) published an alert on glass balustrades in December 2019. It says a single sheet of toughened glass will collapse if it fails. So will some laminated glass, unless something else holds it upright, such as a continuous handrail.

SCOSS recommends laminated glass as the preferred option where possible. The glass should be chosen and fixed so that it stays in place and still acts as a barrier if it breaks. A screen that only divides a space, with no real drop behind it, is the main exception.

Choosing how it is held

Some systems hold the glass by clamping it, so friction alone stops it moving. SCOSS has seen panels slide out of clamps under their own weight. The glass then touches metal or concrete and can break.

It advises that clamp-only fixings are used only where testing or calculation shows they work. Through-fixings or a support ledge can be added. Where panels are held by clips, BS 6180 places them around the edge of the panel, at most 600mm apart.

Getting the design checked early

A CE mark or a Kitemark shows that a product has been tested to a standard. SCOSS points out that this does not by itself make it right for your stair or balcony.

Someone competent should look at the risks early, before the design is fixed. Ask who has done this. If the designer, maker or fitter changes, that assessment should go with the job.

Keeping it in good order

SCOSS suggests regular visual checks of the whole balustrade. A few signs are worth looking for.

Glass touching metal, or glass that has slipped or moved.
Chips or other damage to the glass.
Rust or flaking coatings on metal parts.
Missing or loose fixings, or a loose handrail.

If a panel looks loose or damaged, keep people away from it until it has been repaired.

The building rules

In England, Approved Document K sets out the guidance on guarding. In a family home it gives 900mm for stairs and landings and 1100mm for external balconies. Guarding must resist the loads set out in the British Standards it names.

Where glass forms part of the guarding, the guidance also asks you to check its section on safety glazing. For the design of barriers and infill panels it points to BS 6180.

Wales has its own Part N on glazing. Scotland uses its building standards technical handbooks.

Balconies on taller buildings

In England, the rules on combustible materials cover balconies on some taller buildings. In 2019 SCOSS noted that the laminated glass in common use did not meet the fire classes those rules require. The reason is the plastic layer between the panes.

SCOSS recommends talking to building control about glass in any such balustrade before it is chosen.