Balustrading for stairs, landings, balconies and terraces

The rules every balustrade has to meet

Every balustrade has to satisfy Approved Document K for height and gaps and BS 6180 for load. In a house, guarding is 900mm high on stairs, landings and internal floor edges, and 1100mm on external balconies, roof terraces and flat roof edges. No opening may let a 100mm sphere through, and where children under five are likely the guarding must not be easy to climb, which rules out horizontal rails and slack wires. BS 6180 sets the horizontal load: 0.36 kN per metre inside a single family house, 0.74 on its balconies and roof edges and in flats and offices, 1.5 or more in public areas. That load governs post size, spacing and fixings, so we ask what the building is used for before we quote, and supply drawings and calculations for building control where needed.

Steel bar balustrade

Mild steel bar is the everyday form of metal balustrading and the one to price first: vertical 12mm square or 16mm round bars at under 100mm clear spacing, welded to a flat bar or channel at the bottom, with a flat, round bar or tube handrail on top and 40mm or 50mm square hollow section posts. It is the strongest option for the money, it suits period houses and new builds, and it takes any powder coat colour. Outside, a steel balustrade is hot-dip galvanised first so the zinc protects the welds and the inside of the posts, then powder coated if you want black or anthracite rather than galvanised grey. Inside it can be primed and painted or powder coated straight from the workshop. Decorative work such as twisted bars or cast collars sits on the same frame.

Glass balustrade

A glass balustrade keeps the view and light, but the glass has to be specified for the load. Framed and semi-framed systems hold 10mm or 12mm toughened glass in a steel or stainless frame that takes the load. Frameless glass balustrades fix the glass at the base in a channel or on standoff bolts, and the glass itself is the structure, which means thicker laminated toughened panels, usually 17.5mm or 21.5mm. BS 6180 asks for a handrail on frameless glass unless the panel is laminated and designed to stay in place if one ply breaks, so a rail is not optional on plain toughened glass. It suits balconies, terraces and landings where you want to look through it. It costs more than bar and shows rain and fingerprints, so it is not always right on a working external stair.

Stainless steel and glass

A stainless steel balustrade with glass infill is the standard modern choice for balconies and terraces. We use 42.4mm or 48.3mm tube for the posts and the stainless steel handrail, in grade 304 for inside and sheltered work and grade 316 outside, where road salt and pollution attack the surface. A brushed satin finish hides marks better than polished. Glass clamps hold 10mm or 12mm toughened panels between the posts, or the glass runs in a base channel with the stainless as handrail only. The advantage is that nothing needs painting and the metal is the finish. The cost is higher than galvanised steel, and stainless still needs a wipe down outside to stay bright, particularly near busy roads, where tea staining shows if it is neglected.

Wire balustrade

Wire balustrade uses 3mm or 4mm stainless steel cable strung between posts and tensioned with swaged fittings. It is light, cheap on materials and nearly invisible, which is why it is popular on decks and garden terraces. It has two limits. Horizontal wires can be climbed, which Approved Document K does not allow where children under five are likely, and they are rarely the right choice on a stair. Cables also stretch, so they need retensioning, and the 100mm gap has to hold with the wire pushed sideways under load, which means closer spacing than most people expect. Where it suits, we run it with stainless posts and a steel or timber handrail on decking, low garden terraces and the odd balcony where building control is happy with it.

Perforated and solid panel balustrade

Panel balustrade uses laser-cut sheet steel, 2mm or 3mm thick, folded at the edges for stiffness and fixed to posts or a frame. Perforated patterns, from plain round holes to a design of your own, let light and air through while breaking up the view, so a panel doubles as a privacy screen on a balcony overlooked by neighbours. Solid panels give full screening and a clean face. The holes are too small for the 100mm sphere test to matter and there is nothing to climb, which makes panel the simplest way to satisfy the regulations where children use a landing or balcony. Outside it is galvanised and powder coated; inside it is powder coated or painted. Panels weigh more than bar and a solid panel catches the wind, so posts and fixings are sized for both.

Stairs, landings, balconies and terraces

Where it goes changes what we recommend. On a stair the handrail has to be continuous and easy to grip, 900mm to 1000mm above the pitch line, and the posts fix to the stringer or the side of the flight, so bar or stainless work best. On a landing the balustrade fixes to the floor edge or the joists; glass keeps the space light and a perforated panel screens it. Balcony balustrades go to 1100mm, carry a higher load, take the wind and sit in the weather, so galvanised steel or 316 stainless with resin anchors into concrete are the norm. On a terrace or deck, wire or glass suits the view, but fixings into timber need spreader plates or a steel sub-frame. External handrails on steps and ramps follow the same heights and finishes.

Straight answers on balustrading