I was doing some research for my latest novel and came across this stairway. Not being in the typical architectural loop, I was curious if it’s unique or just one more iteration of a common design.
cantilever or floating stairs are fairly common in Europe…
some countries don’t even require the handrail for domestic use…
There is some serious structural engineering and construction to make that work. But way cool.
Some examples in the link:
Those look a lot sturdier … like they’re not going to pop off the wall with too much weight.
Some don’t have so much as a wall for support.
Those look like Maurits Cornelis Escher might have been the designer.
The most unusual thing about your staircase is that the structural cantilevers under the treads look to have been moulded, perhaps out of fibreglass. There also seems to be only minimal contact with the wall. I presume there must be a hefty stringer, maybe made of steel, to which the cantilevers are attached but it must have to resist quite a lot of twisting motion.
That is an awesome feat.
Interestingly, it is not what I know as a true spiral staircase but a helical one*. If you click on the word “spiral” in that Wikipedia entry, it explains the difference.
- I am not a pedant, but the word pedant is unusual etymologically. It has its roots in - no, sorry, got to go, hairwashing day.
Close … they’re made of carbon fiber. In my novel, I need a name for a fictitious company that makes synthetic diamonds and so I came up with Clear Carbon. A web search turned up this company:
Their portfolio included the stairway that I was curious about. Not sure whether to use the name or try something different (Transparent Carbon?). For now, Clear Carbon works
Clear Carbon, sure. What about Adamantine?
Just because you can design it doesn’t mean that you should !
You can design many forms of stairs that are wonders of engineering…
But don’t forget that design is not just about the ‘structure’
Firmness, Commodity and Delight [Vitruvius]
It might be a miracle of structural design and it also looks stunning - but if a child falls to their death [or is injured] - e.g. passing through the overly open treads or the unguarded sides - or even if an unsuspecting adult user stumbles and falls catastrophically, then it is NOT a good design.
It is not ‘commodious’ !
It is a bad design - even if it looks great !
The worst thing about that is that what happened is the designer’s fault, even if the client asked for a design like that. I see those railingless stairs in glossy publications and wonder how the designers can sleep at night.
This can certainly be done but you can bet that if you live in an urban area, the local building official is going to want some serious engineered drawings for review…or they should, anyway. Those cantilevers /moment connections need to be taken seriously. it’s a detail for high end construction where there is plenty of money and a contractor that would embrace it rather than laugh and dismiss it.
Great as they look, the Euro stairs definitely don’t meet US code. But it looks like the ones the OP posted do.
A couple of years ago, I visited Peru, and went to Machu Picchu. We arrived in the adjacent village of Aquas Calientes in a rainstorm. Our room was on the second floor. The stairs up from the lobby (which was the dining room of a restaurant) was wide and made a 180 degree turn. Our shoes were wet. The material of the stair treads was the same used for the floors throughout the building: highly polished ceramic tile. Think: white glass. The edges were like razors, the rise and run of the stairs were dimensionally inconsistent, not just irregular, but random. There was no handrail, and on the inside of the curve, no wall.
After visiting Machu Picchu, where the steps carved into the mountain use an even worse design (risers often three times that of the treads), and watching Peruvians negotiate these structures, I gave up worrying about safety. There, in Peru, anyway. Caveat Emptor.
But I would never provide a stairway design for a residence (let alone a commercial building) where there were such anomalies. The responsibility of the designer of a building is, as important as is anything else, the life safety of the occupants. And if my client insisted on such a stairway, I would end my relationship with that client.
When I had a subscription to Dwell magazine, my sport when it arrived was to quickly thumb through it just looking at stairs and go, “That’s illegal…that’s illegal…that’s illegal…”
The picture in the OP might meet code on paper in the US, but I’m a little skeptical. You’re not supposed to be able to push a 4" diameter wood ball through the railing or risers with some exceptions for the little triangle space between guard, tread and riser. On paper (or screen?), the cables may be less than 4" apart, but without intermediate supports approximately 3’ apart, the cables will splay apart and let the ball through in the real world.