Joinery · Case study
Floating Blackbutt Stairs
- Location
- Glenhaven, NSW
- Year
- 2023
- Duration
- 5 weeks
- Category
- Joinery
Twelve cantilevered blackbutt treads, matte hard-wax lacquer, frameless glass balustrade with a powder-coated steel handrail.
Why this needed an engineer.
Floating treads look effortless on a drawing. In real life each tread is a cantilever, anchored only at the back, taking the full live load of foot traffic plus dynamic load from people running down them. Get the engineering wrong and the tread bounces. Get the connection wrong and the timber splits over the years as it tries to lever itself off the wall. Add a glass balustrade and a black steel top rail through the same tread set and you've got three materials with different thermal coefficients that need to coexist without anything cracking, settling, or working loose.
The engineering thinking.
Each tread is a 60mm-thick blackbutt slab housed into a continuous steel stringer concealed behind the wall lining. The steel does the work; the timber is the visible part and the foot surface. We designed the stringer to a deflection limit of L/600 (more than twice the code minimum) so even the bouncier treads at midspan feel solid underfoot. Glass balustrade is point-fixed through stainless studs into the side of the steel stringer with rubber isolation washers, not into the timber. The black steel top rail is fixed only at the ends so the glass can flex independently without stressing the timber treads. Matte hard-wax lacquer was the right finish choice for a high-traffic surface: durable enough to take decades of foot wear, repairable in patches without a full re-finish.
- Blackbutt (Eucalyptus pilularis), 60mm slab treads
- Concealed structural steel stringer (powder-coated)
- 12mm toughened glass balustrade panels
- Black powder-coated mild steel top rail
- Hard-wax matte lacquer
Twelve treads, no creaks, no bounce, no visible fixings. Three years in and the finish on the high-traffic treads hasn't lifted. The client uses the words 'still looks new' which is the only review that matters.
Commission
Build something like this.
Tell us the brief, we'll reply with a thoughtful response within one business day.
Start a quote