Structure, Design, and Installation of Helical Staircases

Helical staircases are among the most striking and functional staircase designs available today. Known for their sweeping curves and sculptural flow, these stairs are popular in both residential and commercial architecture. But what makes a helical staircase different from a spiral stair? And how are they made?

This blog offers a clear, practical explanation of helical staircases, from structure to installation, with key insights for architects, designers, and contractors.

What Is a Helical Staircase?

A helical staircase, sometimes called a curved stair, follows a circular or elliptical path, but unlike a spiral stair, it doesn’t have a central support spindle. Instead, it relies on curved stringers and radiused treads to form a self-supporting helical structure.

This design allows for a more open, elegant feel and offers greater flexibility in size and shape. Helical stairs can be wide and spacious, with a smooth, continuous rise, ideal when creating feature staircases.

Double Helical Staircase

Although it appears to be a single structure, it is actually composed of two separate spiral staircases intertwined to resemble a DNA strand.

One famous historical example is the double helix staircase at Château de Chambord in France, thought to have been influenced by Leonardo da Vinci in the 16th century. This early form of a double helical staircase showed how geometry and engineering could combine to create architectural art.

This example is not a steel structure, but it follows the same principles that we would follow to create a double helical staircase.

Helical vs Spiral: What’s the Difference?

At a glance, spiral staircases and helical stairs can look similar. But their structure is quite different.

• Spiral stairs have a central column and the treads spiral tightly around it.
  
• Helical stairs have no central support and feature curved stringers on each side.
  
• Spiral stairs are compact, often used as a fire escape or space-saving solution.
  
• Helical stairs are more open, making them ideal for staircase features in large spaces.
  

This difference in structure also affects how the load is transferred. In helical stairs, the load passes through the stringers and into the floor at either end. That requires precise engineering and fabrication.

The Role of Fabrication in Steel Helical Staircases

Every helical staircase starts with accurate planning and modelling. At Smart Steels, we use precision CNC cutting to shape each component to exact tolerances. This ensures the curvature of the treads and stringers align perfectly during assembly.

The seamless welding process is key to creating the smooth, unbroken appearance that makes helical staircases so visually appealing. Welds are ground and polished for a clean finish that hides the joints completely.

These steel helical staircases are usually made in sections off-site. This prefabrication means better quality control and faster installation on site. It also allows us to test fit all parts before transport, ensuring accurate alignment when the structure is finally installed.

Installation Sequence: How It’s Done

Installing a helical staircase involves several steps, each requiring care and accuracy:

1. Workshop Prefabrication – All parts are CNC-cut and preassembled.
   
2. Site Preparation – We ensure the base and upper floors are ready for fixing.
   
3. On-Site Alignment – Using 3D layout drawings and laser levels, we align the structure precisely.
   
4. Fixing and Welding – Each section is bolted or welded into place, checking tolerances at every stage.
   
5. Finishing – Surface treatments or coatings are applied as specified.
   

This process ensures a strong, secure, and beautifully crafted staircase, with minimal disruption to the site schedule.

Use Cases for Helical Staircases Made From Steel

Because of their aesthetic appeal and smooth structure, helical staircases suit a range of environments:

• Private residence: As a centrepiece in entrance halls or modern open-plan homes.
  
• Retail and commercial: Providing both vertical access and architectural value.
  
• Hotels and hospitality: Enhancing guest areas with grand, curved stairs.
  
• Historic renovations: Replicating the character of features like the de Chambord staircase.
  
• Public buildings: Where a double helical staircase can manage two-way traffic in a busy environment.
  

They’re also a great alternative to a steel spiral staircase when more walking comfort or design impact is needed.

How Smart Steels Can Help

Precision matters in fabrication. That’s why we’ve created a detailed specification sheet outlining tolerances for helical staircases.

Smart Steels is a UK-based expert in metal fabrication, steel welding, and custom staircases. From small residential projects to large commercial fit-outs, we deliver craftsmanship, precision, and value.

Contact us:

📞 020 8640 6999
📩 sales@smartsteels.co.uk

FAQ

1. What is the difference between a spiral stair and a helical staircase?

A spiral stair has a central support column, while a helical staircase uses side stringers and has no centre. Helical stairs offer a smoother, wider walk and more design freedom.

2. Are helical stairs safe and strong?

Yes. When properly fabricated and installed, they are structurally sound. Load is transferred through curved steel stringers to the floors, providing excellent support.

3. How much space do I need for a helical staircase?

Space requirements vary depending on the diameter and shape. We provide custom designs to suit your floor plans.

4. What materials can be used?

We typically fabricate in mild steel or stainless steel. Treads and handrails can be finished in timber, glass, or other materials.

5. Can I customise the staircase design?

Absolutely. All our staircase designs are bespoke. From dimensions to finish, we work to your project needs.