CANTILEVERED STAIRCASES, OR FLOATING STAIRCASES

Cantilevered staircases are rapidly becoming a signature element in contemporary home design, especially among property owners seeking sleek, space-saving solutions. Unlike traditional staircases supported by visible stringers, cantilevered staircases appear to float effortlessly off a single wall, creating a dramatic visual impact while maximising open space. This minimalist aesthetic aligns perfectly with current trends favoring clean lines, uncluttered footprints, and architectural boldness in open-plan living areas.

What sets cantilevered staircase designs apart is their structural ingenuity; each tread is anchored directly into a load-bearing stringer, higgen in a wall, distributing weight efficiently and eliminating the need for visible supports underneath. This not only enhances the illusion of a floating staircase but also allows for greater design flexibility in both new builds and renovations.

Whether you're renovating a city apartment or designing a countryside modern home, understanding the fundamentals of cantilevered staircase design is essential for achieving a striking, functional centerpiece.

How Do Cantilevered Staircases work; The Engineering Behind The Illusion

Cantilever is an old English word describing a structure, beam or plank that is fixed at one end with the other end reaching out into a void space, for example; a juliette balcony or a cantilevered bridge, or in our case, a Cantilevered Staircase, or Floating Staircase.

Cantilevered staircases create a striking floating effect, but their visual lightness belies a robust structural framework. These designs rely on precise engineering to safely transfer loads from each tread into a secure wall or support structure. Unlike traditional staircases with visible stringers or supports underneath, cantilevers embed treads directly into a load-bearing wall to resist bending and shear forces.

A 'cantilever' beam transfers its vertical load back to a fixed support. The fixed end is where there is the most stress, and the free end is where there is the most deflection. In other words, as the load moves along the length of the beam, deflection gradually increases until it reaches the end, at which point deflection is at its maximum.

In simple terms, think of the old Pirate expression, 'Walking the Plank'. Captives were forced to walk along a wooden plank, cantilevered over the side of the ship. The plank is anchored to the ship's deck at one end, and the poor victim is made to walk out along a long plank until the deflection at the very end is so great that they tip off the end of the plank.

In the case of our cantilevered staircases, we need to ensure the deflection at the free end of the plank - the stair tread, is kept to an absolute minimum. To achieve this, the fixed support is a patented system consisting of a jigsaw cut, 12mm thick steel plate, resin anchored into a solid wall, with rigid steel arms bolted on to the plate to support each individual stair tread.

Structural Engineers calculate the deflection

Our Structural Engineers calculate the deflection based on several factors; the materials used in the construction of the staircase, the length and width of the treads, the likely maximum load, ie the weight of a person on the tread, and the position of that load on the tread. Let's assume the average weight of a man is 13 1/2 stone or 188 kg, the tread is 900mm long and 250mm deep, and the man (the vertical load) stands on the very end of the tread. The deflection at that point would be approximately 1mm. However, in practice, the man would likely walk up the centerline of the tread, and here the deflection would be practically zero.

Utilising our Structural Engineer's calculations enables us to design an 'invisible' steel skeleton in such a way as to minimise the deflection, making it perfectly safe to walk up and down the cantilevered staircase with no discernible flex, or 'bounce'.

By the time the wall is plastered to hide the steel plate, and the Oak treads are slid over the steel arms, all you see are the Oak stair treads floating in mid air.

Materials and Finishes for Floating Staircases

The choice of materials plays a significant role in both the appearance and performance of a floating staircase. In the UK, homeowners tend to favour a combination of timber, glass and metal to achieve a balanced and contemporary look.

Hardwood timber is often used for the treads, with Oak being one of the most popular choices due to its durability and attractive grain. We use American White Oak because it's a commercially grown crop with more grown each year than is harvested. It can also be finished in a range of colours, from light and natural or 'Limed', to darker, richer shades, allowing the staircase to complement existing flooring and furniture.

Glass is commonly used for balustrades, providing safety while maintaining transparency. Toughened and laminated glass ensures strength and compliance with regulations, making it suitable for family homes. Frameless glass panels are particularly popular as they enhance the floating effect.

Metal components, typically steel, form the hidden structure of many floating staircases. These elements are engineered for strength and can be powder coating to any RAL colour. Stainless steel and painted steel are also both widely used depending on the desired look.

By combining these materials, we create staircases that are not only visually striking but also built to withstand everyday use.