Creating the perfect floating stair — one that appears to lightly hover above the ground and smoothly rise to unknown higher levels — is challenging.
There are countless considerations to make from tread length, to step depth, riser height and handrail width. There are also several design options to contemplate when detailing such a stair: Will it have wall supports or be a sturdy mono-stringer? Will it be dramatically suspended from a series of ceiling-hung cables, or will it feature a standard set of stringers that unite the stair as a singular object? And how can a balustrade be detailed such that it provide safety and code compliance, without diminishing the “floating” effect of the stair?
Diagram of floating stair tread insert with wall-inserted brackets; Image via Diamond Stairs
Fontanot floating stair with glass balustrade
Before getting into these questions, it’s important to pay attention to the construction restraints you’re working within. Knowing details about the building code is going to be step one in designing a floating stair, since consistent conversation surrounding their safety is always top of mind amongst homeowners, developers and other architects. Like everything else in life, love and construction, safety must come first.
So let’s talk about how to make one properly — a staircase that adheres to code, is pretty to look at and easy to walk up and down.
Construction codes vary from country to country and what may be deemed safe in Spain is not necessarily going to be appropriate in California. Even the building typology makes a difference in designing a floating stair. In some cases across the United States, local jurisdictions have developed their own building codes.
For example, the Chicago Municipal Code applies to the entire city of Chicago, while other towns use specific laws standard to construction in their own communities. Most major cities, however, have adopted the International Building Code created by the International Code Council. These regulations are based on a model building code, which is updated every three years.
Solid Concrete Studio + Gallery by ASWA features a mono-stringer cantilevered staircase with a single landing and metal railing. Set in Bangkok, this type of stair with limited railing in a commercial space may not be appropriate under American building codes.
The beauty behind a floating staircase is that it provides an open, modern and sleek look in any setting. Depending on the stringer and material used for the treads, floating stairs can look virtually weightless. When designing for residential use, construction codes are a bit more relaxed. With public-facing stairs, however, architects must follow a stricter code. If it’s the primary means of egress between floors, it also must be more carefully considered.
Per the IBC, a floating stair must comply with the following minimal measurements:
- The step rise should be a minimum of 4 inches and a maximum of 7 inches
- The step depth should be a minimum of 11 inches on commercial applications
- Handrails should not be less than 36 inches in height
- Spindles or cables should not be placed more than 4 inches apart
- Each step must be able to bear at least a 300-pound concentrated load
Floating Waves by Siller Stairs includes a series of transversing wood treads attached to wavy glass guardrail and adjacent wall. Private, residential projects in the U.S. adhere to a less-strict construction code depending on location across the country. But the ample glass featured here and appropriate step rise provide more safety for users.
Design and Detail Second
Once you’ve thoroughly researched the environment in which you’re working, it’s time think about the aesthetic of the stair and how to best create it with the right safe and strong attachments. There are two common ways to create a floating staircase: cantilevered off the wall and cantilevered off of a single or double stringer.
Diamond Stairs, a Canadian manufacturer who creates prefabricated steel staircases that cantilever off the wall, offers IBC-compliant options and details on how their universal stair kits precisely get programmed into a space. Their kits come in four sizes to accommodate various floor-to-floor heights and they offer a maximum tread size of 42 inches.
Each kit comes with a set of brackets that bolt to every tread and a series of telescoping vertical uprights that span the height of the wall and interface between the DS system and the structure. This hidden back-end system makes for a seamless look and a sturdy staircase.
Diamond Stairs’ universal cantilevered stair kit comes with an integrated system of brackets and uprights that create a strong and effortless-looking floating staircase. Diagrams via Diamond Stairs
Other bespoke stair companies like Siller Stairs also sell cantilevered-off-the-wall designs with varying tread material options. With Siller, you can custom order striking yet subtle glass balustrades or guardrails, speciality wood or metal railings as well as tread-to-ceiling spindles.
Mylen Stairs specializes in mono-stringer and double-stringer floating staircases. These are great options for multi-level staircases situated in commercial or public environments like the lobbies of hotels, offices or retail spaces for many reasons. First, open risers allow light to filter in between the treads and provide extra brightness for spaces below.
Second, these staircases call attention to the materials used. Whether the treads feature a specialty wood or stone and the stringer is stainless steel with a powder coat finish, you have the power to create a more personalized set of material combinations with mono- and double-stringer floating staircases.
Mono-stringer floating staircases with metal railing and spindles; Image via Eva Furniture
At the end of the day, a floating staircase is a transitional element in architecture. It’s functional, but can also be an astounding, aesthetically-pleasing structure if designed and detailed well.
These stairs can look both light and airy and be able to withstand the weight of a standard staircase at the same time. That’s why fundamental technicalities like building code, weight, width and spatial length will help you specify the best materials needed or custom-design your floating staircase to fit any unique environment.