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A glass balustrade is designed to resist a horizontal push along its top, called a line load, measured in kilonewtons per metre. The figure depends on how the building is used: a staircase inside a house takes the lowest load, and a crowded public space the highest. BS 6180 is the code of practice for barriers, and it designs to the loads in BS EN 1991-1-1 and its UK National Annex. Your designer, engineer or building control body confirms the load for your project.
Which line load applies to my barrier?
Our balustrade checker quotes these figures from BS EN 1991-1-1 and its UK National Annex. The load is applied horizontally at handrail height.
| Where the barrier is | Use category | Line load |
|---|---|---|
| Stairs, landings and floor edges inside a single-family house | A | 0.36 kN per metre |
| That house's balcony, Juliet balcony or roof edge | A | 0.74 kN per metre |
| Flats, hotels and other residential buildings | A | 0.74 kN per metre |
| Offices and work areas | B | 0.74 kN per metre |
| Stairs, landings and corridors in a public building | B, C1 to C3 | 0.74 kN per metre |
| Light access stairs and gangways up to 600 mm wide | B | 0.22 kN per metre |
| Shops, restaurants, cafes and bars | C1, D | 1.5 kN per metre |
| Pedestrian areas in a car park | F, G | 1.5 kN per metre |
| Assembly areas, shopping malls and crowds | C3, C5 | 3.0 kN per metre |
Grandstands, stadia, areas with fixed seating close to the barrier, and barriers that must stop a vehicle are set by a specialist design. The checker does not give a figure for them.
How do I find the right row?
Step 1: Say what the building is used for
A private house, flats, an office, a shop or a public space. The use sets the category, not the look of the barrier.
Step 2: Say where the barrier is
Inside on a stair or landing, or outside on a balcony or roof edge. The same house moves up a row outside.
Step 3: Read the load off the table
Use the checker to confirm the row. It prints the load, the category and the height it expects.
Step 4: Check the height
Measure from the finished floor level to the top of the barrier and compare it with the heights below.
Step 5: Prepare the rest of the specification
Draw the run in the balustrade designer, and gather the site details in our survey and specification checklist.
How high must the barrier be?
The checker uses Approved Document K for minimum heights:
- Inside a single-family house: 900 mm at stairs, landings and the edges of internal floors.
- External balconies, Juliet balconies and roof edges: 1100 mm.
- Flats, offices, shops and assembly areas: 1100 mm at landings and floor edges.
- Stairs and ramps in other buildings: 900 mm.
A 100 mm sphere must not pass through any gap in the guarding. Read the rules in Approved Document K on gov.uk, and see Juliet balconies for openings over a door or window.
Why does a free-standing barrier need laminated glass?
Where a handrail on its own supports takes the load, the glass is an infill panel. Where there is no handrail, the glass is the barrier and has to keep holding people back even after a pane breaks. BS 6180 is explicit that a free-standing barrier with no handrail should be laminated glass, and toughened laminated is the usual answer.
A bolted panel is normally toughened laminated even with a handrail, because the holes concentrate stress, and a bolted pane that breaks must not leave the opening.
Does a base channel change the design?
Yes. A continuous base channel makes the panel a cantilever. The whole horizontal load arrives as a bending moment at the bottom of the glass, and the same moment goes into the channel, its fixings and whatever the channel is bolted to. On a free-standing barrier the sway at the top often decides the thickness, and BS 6180 sets the deflection limit to work to.
That is why we never pick a thickness from a chart. It comes from the load, the height, the span, the fixing and what must happen if a pane breaks. Our balustrades guide explains how the designer and quote work.
This is general guidance, not a structural calculation. Have the supporting structure and its fixings checked by an engineer, and follow your building control body's advice.
Where to go next
- Find your load: open the balustrade checker
- Glass balustrades
- Where the rules ask for safety glass
- Toughened, laminated and annealed glass
Questions we get asked
What does 0.74 kN per metre mean in plain terms?
It is the horizontal push, along each metre of the barrier's top edge, that the design must resist. A higher figure means a stronger barrier.
My house balcony is outside. Which load applies?
A domestic external balcony, Juliet balcony or roof edge is 0.74 kN per metre, a row above the house's internal stairs.
Can I use the checker instead of an engineer?
No. It shows the standard's design loads and checks your height. It does not size a panel, design a fixing or certify a barrier.
Do you sell balustrades online?
A post-and-clamp run the designer can price can go in your basket, sometimes at a provisional price we confirm by hand before cutting. Other designs, and all commercial use, are priced by hand.
Contact the team with your order reference and the step you need help with, or search all help topics.