Open-riser and floating hardwood stairs

What people mean by a floating stair

Two different things, usually. An open-riser stair has treads with nothing between them. A cantilevered or 'floating' stair has treads that appear to come out of the wall with no visible stringer. They are often specified together and they are structurally very different problems.

Both are buildable in hardwood. Both cost considerably more than a box stair, and both are decided at framing, not at finishing.

The guard rule is what constrains the design

Ontario requires guards at the side of a dwelling stair to be at least 900 mm high, measured from the tread nosing line, and the openings in a guard must not permit the passage of a sphere of a defined diameter — the rule exists so a small child cannot fall through.

On an open-riser stair the space between treads comes under scrutiny for the same reason. This is the constraint that most often forces a redesign late, because the architectural drawing showed a gap that the building department will not accept.

Confirm the specific requirement with your municipality before anything is fabricated. The limits differ by occupancy and the interpretation of guard openings on open risers is the part worth getting in writing.

Structure comes first

A cantilevered tread is a lever with a person standing on the end of it. The load goes back into a steel stringer, a reinforced wall, or a hidden bracket bolted to structure — and that structure has to exist before the drywall does.

Retrofitting a cantilevered stair into a finished house means opening the wall. That is not a stair job with a wall repair attached; it is a structural job with a stair on the end of it, and it should be priced and sequenced that way.

Wood selection changes on an open riser

Both faces of every tread are visible, so the material has to be presentable on all sides and thick enough to look substantial — typically much thicker than a capped tread on a box stair. That means solid stock, well dried, with the grain read and matched across the flight.

Movement matters more here too. A tread that is visible from below shows a cup or a twist that a closed stair would hide behind a riser.

The honest cost conversation

Open-riser and cantilevered stairs sit well above the published per-step range for a conventional hardwood stair, because the labour is fabrication rather than installation and because the structure usually needs work. Anyone quoting one at box-stair prices has not understood the drawing.

The right sequence is a drawing, a structural review, a building-department conversation, and then a price.