Floating stairs — structural and safety overview
Floating stairs appear visually light, but their structure is demanding. Here are the core systems, material considerations and safety points architects should know.
Main structural systems
1) Cantilevered treads
Treads anchored into a reinforced concrete or steel spine wall. Requires precise engineering and strong wall structure.
2) Central spine beam
A concealed steel beam carries treads on welded or bolted brackets. One of the most common floating systems.
3) Hidden stringers
Stringers integrated into walls or under treads provide support while maintaining a clean look.
4) Glass structural balustrades
Laminated glass panels can function structurally, reducing the need for visible supports.
Material considerations
- Timber: requires thicker treads than standard stairs to resist bending.
- Steel: ideal for cantilever systems and thin profiles.
- Concrete: heavy but very stiff; used primarily for wall-anchored treads.
- Glass: always laminated and often heat-treated for strength.
Safety and code issues
- Open riser gaps usually limited to 100 mm.
- Handrails required unless stair is secondary or decorative.
- Slip-resistant tread surfaces highly recommended.
- Structural deflection limits are more strict than for normal stairs.
Common design mistakes
- Underestimating wall strength needed for cantilevers.
- Using undersized timber treads leading to excessive flex.
- Poor acoustic performance from hollow steel systems.
- Insufficient lighting on open-riser designs.