Floating staircases — cantilevered steel

A floating staircase has treads that appear to project from the wall with no visible support underneath. The structural reality is that each tread is anchored to a hidden steel armature embedded in the wall — a "wall pocket" — that cantilevers the load back into the building structure. Done right, it looks like the treads are growing out of the drywall.

Rarely, and never well. Floating stairs require a continuous structural element behind the drywall — typically a built-up steel beam or doubled studs with steel reinforcement — that runs the length of the stair and is engineered to take the cantilever moment from each tread. That has to be installed during framing, before drywall goes up. Trying to retrofit one means opening the wall, structurally rebuilding it, and re-finishing — at which point you have spent more than a new build install.

Floating stairs are the most expensive stair type we build because the cost driver is the engineering and the embedded wall structure — not the visible part. A simple mono stringer stair with the same tread count costs roughly half as much because the structural work is less complex. The final price depends on tread count, tread material, railing system, and the complexity of the wall pocket framing. <a href="/request-a-quote/">Contact us for a project-specific quote</a>.

Yes, when engineered and built correctly. Each tread is a structural cantilever sized by an engineer to take the BC Building Code live load (1.9 kPa for residential, more for commercial) with a deflection limit of L/360. The wall pocket framing is designed for the moment at each tread. We have built dozens of floating stairs across Metro Vancouver and they perform exactly like any other engineered structural element.

Railings on floating stairs are usually frameless glass or thin steel rod. Glass is the most common — it visually disappears, which preserves the floating effect. The glass panels need to be structurally laminated and the standoff hardware has to be engineered for the lateral guard load (0.7 kN/m for residential per BCBC). The glass typically anchors into the side of each tread or into a continuous channel along the wall side.

Practical tread depths for residential floating stairs run 10–14 inches. At 14 inches, the cantilever moment at the wall connection is meaningful — roughly 120 kg × 36 cm (the centre of a loaded tread) = about 420 N·m per tread, and the wall pocket structure has to handle that plus safety factor. Deeper treads are possible but require proportionally heavier embedded structure. Going beyond 16 inches usually doesn't make sense unless the design has no alternative.

The drywall closes around each tread bracket with a sleeve detail that hides the bracket entirely. The finish is standard Level 5 drywall with a small return at each tread penetration. Some projects use a tall continuous plinth or a stone/tile feature wall instead of drywall — both work, but they add coordination requirements between the fabrication and the finish trades. We work through these details during shop drawings.

Yes, and sometimes it's actually easier than installing over a wood-framed wall. Each tread bracket anchors directly to the concrete with epoxy-set anchors or post-installed rebar connections, sized by the engineer for the cantilever load. The concrete has to have enough edge distance and depth to develop the anchors, but in most residential basement walls and commercial tilt-up walls, there's plenty to work with.

Each tread has a steel plate or square tube element either bolted or welded into the back edge that slides over the wall bracket and is fastened with concealed bolts. The connection detail is engineered to transfer the full cantilever moment and vertical load. Most of our floating stair treads use a steel sleeve inside the hardwood that the bracket slides into — this makes installation clean and allows the treads to be installed after the wall finish is complete.

The bottom tread on a floating stair usually sits directly on the finished floor or on a small concealed base. Because the loads are transferring horizontally back to the wall beam through every tread, the bottom of the stair doesn't need to carry the full load of the stair — just its own local reaction. This is part of what gives floating stairs their signature look.

They can be, if the installation has any play in the bracket connections. Well-built floating stairs are silent — the brackets are torqued tight, the tread-to-bracket connections use isolating washers where metal would meet metal, and the wall pocket structure is properly tied into the supporting building frame. Creaking almost always traces back to an under-torqued connection or a structural element that wasn't fully tied in.

Changing which wall carries the floating stair during construction is possible but expensive. It usually means ripping out the partially installed wall structure, re-engineering the cantilever loads for the new wall location, fabricating a new wall pocket steel, and re-framing. Change requests after the original wall is structurally complete add significant cost depending on what is already built. Locking the design before framing starts is by far the cheaper path.

They can, but the engineering is more demanding because commercial live loads are higher (4.0 kPa vs 1.9 kPa residential), and commercial egress code sometimes requires handrails and guards that conflict with the floating aesthetic. We have built floating stairs for restaurants, retail, and private office spaces where the live load is manageable and the stair is not an egress stair. Main egress stairs in commercial buildings are almost always a different typology.