What is a Cantilevered Staircase? The Engineering Behind Floating Stairs

You walk into a modern home, and your eyes are immediately drawn upward. A staircase appears to defy gravity itself—each step jutting out from the wall with no visible support underneath, as if suspended in mid-air. Light streams through the open space between the treads, and the entire structure seems to challenge everything you thought you knew about how stairs should look. This is a cantilevered staircase, and it’s quickly becoming the signature element in contemporary custom homes across British Columbia.

But how does something that looks so impossible actually work? And more importantly, is it safe? The engineering principles behind these floating stairs reveal why they’ve become such a coveted feature in luxury home design—and why they require specialized fabrication expertise to execute properly.

Before diving into how cantilevered stairs work specifically, it helps to understand what a cantilever actually is.

Think of a diving board—it’s the perfect everyday example of a cantilever. The board is securely bolted to the pool deck at one end, allowing the other end to project out over the water. When someone walks to the edge and bounces, all that force travels back through the board to where it’s anchored. The diving board doesn’t need support pillars underneath because the engineering happens at the fixed connection point.

This same principle appears throughout our built environment. Building balconies often cantilever out from the structure without visible supports below. Airplane wings function as cantilevers, extending from the fuselage without external bracing. Highway signs project over the roadway from a single pole. In each case, the magic isn’t in the extended portion—it’s in the incredibly strong connection point that makes the extension possible.

The cantilever is considered one of the three fundamental structural methods in construction, alongside post-and-beam systems and arch construction. What makes cantilevers unique is how they handle load: they create a downward thrust at the support point while simultaneously dealing with significant bending forces throughout their length. This is why cantilever construction remained relatively rare in architecture until the development of steel and reinforced concrete gave engineers the materials capable of handling these complex forces.

When this cantilever principle is applied to staircases, something remarkable happens. Each stair tread functions as an individual cantilever beam, anchored firmly into a wall at one end and extending freely into space at the other. The result is what’s commonly called a “floating staircase” or “floating stairs”—though of course, nothing is actually floating. The stairs are very much held in place, but the support system is hidden from view, creating that stunning illusion of weightlessness.

A cantilevered staircase works by transferring the load from each step back into a robust steel framework that’s embedded deep within a reinforced wall. When you step on one of these treads, the weight doesn’t just push straight down—it creates a turning force (what engineers call a “moment”) at the point where the tread connects to the wall. The hidden steel structure is engineered to resist this turning force, preventing the tread from rotating or sagging under load.

This is fundamentally different from how traditional staircases distribute weight. In a conventional staircase, visible stringers (the diagonal supports running along the sides) or a central support beam carry the load through multiple contact points to the floor. The weight is spread across the entire structure. With a cantilevered system, all loads funnel back to the wall connection, which means that connection point must be extraordinarily strong and precisely engineered.

What you can’t see from the side is what makes cantilevered stairs possible. Behind the wall finish—whether it’s drywall, plaster, or another material—lies a carefully fabricated steel support system. In most residential applications, this takes the form of a steel stringer or framework that’s been custom-built to match the exact specifications of your staircase.

The installation process typically involves one of two approaches. In the most common method for true cantilever stairs, fabricators create a steel stringer that gets anchored directly into a load-bearing concrete or masonry wall. Heavy-duty steel pins, bolts, or resin anchors embed deep into the wall’s core structure, creating a connection strong enough to handle the full weight of the stairs plus the live load of people using them. The steel stringer extends horizontally along the wall at the location of each tread, with attachment points for the visible treads you’ll eventually walk on.

The wall is then built around this steel framework, completely concealing it from view. When you look at the finished staircase, you see only the treads appearing to emerge directly from the wall surface—no brackets, no visible bolts, no indication of how these steps are actually supported. This is the true “full cantilever” design that creates the most dramatic floating effect.

In some cases, particularly when dealing with larger spans or when the adjacent wall isn’t a solid load-bearing structure, fabricators may use what’s called a “semi-cantilever” design. This involves offsetting the steel support to one side rather than completely hiding it within the wall. The visual effect is similar—the stairs still appear to float—but the engineering approach is slightly different, often involving a visible stringer that’s painted or finished to blend with the wall.

 

The visual impact is the most obvious reason homeowners gravitate toward cantilevered stairs, but the benefits extend beyond aesthetics alone. These staircases fundamentally change how light and space work in your home.

Traditional staircases with their stringers, risers, and support posts create visual barriers that can make spaces feel closed in. A cantilevered staircase does the opposite. Light flows freely through the open spaces between treads, traveling from upper floors down to lower levels in a way that’s impossible with conventional stair construction. This is particularly valuable in modern open-concept homes where preserving sightlines and creating a sense of spaciousness are priorities. In Vancouver and Burnaby, where square footage comes at a premium, this ability to make a room feel larger and more open has real value.

The minimal footprint also matters from a practical standpoint. Without bulky support structures taking up floor space, the area beneath and around the staircase remains usable. This can be crucial in homes where every square foot counts, or in renovation projects where you’re working within existing spatial constraints.

From a design perspective, cantilevered stairs serve as a focal point that immediately signals a commitment to contemporary, high-end design. They’re the kind of architectural element that makes a statement without being ostentatious—sophisticated rather than showy. The clean lines and minimalist aesthetic complement modern interior design approaches while still allowing for customization through material choices and railing styles.

Not every home can accommodate a cantilevered staircase without modification, which is why understanding the structural requirements is important early in the planning process. The most critical factor is the wall where the stairs will be anchored. This must be a load-bearing wall—meaning it’s part of the structural support system for your home—or it must be reinforced to become one.

Solid concrete or masonry walls are ideal for cantilever staircase installation because they provide the mass and strength needed to handle the loads. Wood-framed walls can sometimes be reinforced to accommodate floating stairs, but this typically requires significant structural work, including adding steel or engineered lumber supports within the wall cavity. Stud walls or partition walls that aren’t load-bearing will need alternative support solutions, which might involve additional posts or a different structural approach that maintains the floating aesthetic while providing adequate support.

The foundation below the supporting wall also matters. Because cantilever stairs create significant overturning forces at the wall connection, the foundation must be capable of handling these loads. In some retrofit situations, this might require foundation reinforcement or modifications—something your structural engineer and fabricator will assess during the planning phase.

Building code compliance is non-negotiable. In British Columbia, cantilevered stairs must meet BC Building Code requirements for rise and run dimensions, load capacity, railing height, and balustrade spacing. Professional structural engineering certification is typically required, and the installation will involve multiple inspection points to verify safety and compliance. This is specialized work that requires fabricators who understand both the engineering principles and the local regulatory environment.

While the hidden steel framework is typically a given in cantilevered stair construction, you have considerable flexibility when it comes to the visible elements—primarily the treads and railings. The tread material you choose will dramatically impact both the look and feel of your staircase.

Wood remains the most popular choice for residential applications. Oak, walnut, maple, and other hardwoods bring warmth and natural beauty while still maintaining that modern aesthetic. Wood treads are typically 2 to 3 inches thick, substantial enough to feel solid underfoot while remaining visually light. The treads can be finished to show the natural grain and end-grain, emphasizing the fact that these are solid pieces of material, not hollow facades.

For homeowners seeking a more industrial or ultra-modern look, steel treads offer a sleek alternative. These can be powder-coated in various finishes or left with a raw steel appearance that ages over time. Glass treads take the floating effect even further, allowing light to pass not just around the stairs but through them. Concrete is another option, particularly effective in contemporary designs, though the weight of concrete treads requires additional structural considerations.

The railing system is equally important to the overall effect. Glass railings are a natural pairing with cantilevered stairs because they maintain the openness and don’t block sightlines. Horizontal steel cables or bars create an industrial aesthetic while preserving the view. Vertical balusters, whether in steel, wood, or other materials, offer more traditional railing while still keeping the overall look modern. Some homeowners opt to forego railings altogether on one side, though this requires careful attention to building code requirements regarding balustrade spacing and safety.

This is often the first question that comes up when people see cantilevered stairs for the first time. The honest answer is that properly engineered and installed floating stairs are just as safe as traditional staircases—and in some ways, they’re actually safer.

The engineering behind these stairs is rigorous. Professional structural engineers calculate the exact loads, bending moments, and deflection limits to ensure the stairs can handle well beyond normal use. The steel support structures are designed with significant safety factors built in, meaning they can support several times the expected weight. The connections to the wall are over-engineered precisely because the consequences of failure would be severe.

Building codes impose strict requirements on tread spacing, railing height, and the maximum gap between balusters or between individual treads. In most jurisdictions, the gap between treads cannot exceed 4 inches, ensuring children and pets cannot slip through. When properly installed with code-compliant railings, cantilevered stairs provide secure handholds and fall protection.

The open riser design—the fact that you can see through the gaps between treads—makes some people nervous initially, but it actually provides excellent visibility of who’s ascending or descending the stairs. This was recognized as a benefit as far back as the Renaissance, when architect Andrea Palladio praised staircases that were “void in the middle” specifically because you could see whether someone was already on the stairs.

The key to safety is working with experienced fabricators who understand the engineering requirements and have a track record of successful installations. This isn’t a DIY project or something to trust to general contractors without specialized expertise. The precision required in the fabrication and installation means you want craftspeople who’ve done this work before and can navigate both the technical and regulatory requirements.

A cantilevered staircase represents a significant investment in your home, both financially and architecturally. When executed properly, it becomes a defining feature that elevates your entire space—a perfect marriage of engineering precision and artistic vision. The floating effect, the play of light through open treads, and the sheer visual drama all contribute to creating something that transcends mere function.

If you’re planning a custom home, a major renovation, or simply exploring what’s possible in modern staircase design, understanding how cantilevered stairs work is the first step. The next is connecting with fabricators who have the expertise to turn that vision into reality.

At Metal & Wood Products in Burnaby, we specialize in custom metal fabrication, including cantilevered staircases that meet both engineering requirements and aesthetic goals. With 50 years of experience in metal fabrication and a portfolio of stunning residential and commercial projects across British Columbia, we understand what it takes to create floating stairs that are as structurally sound as they are beautiful.

Whether you’re drawn to the full cantilever design with its completely hidden support structure, or a semi-cantilever approach that balances aesthetics with structural practicality, we’ll work with you to develop a solution that fits your space, meets code requirements, and delivers that coveted floating effect.

Contact Metal & Wood Products at (604) 879-2901 or get a custom quote on your project. Let’s turn that vision of floating stairs into a reality.