Post Tensioned Stone Staircases

Engineering Elegance

Post-tensioned staircases represent the most technically advanced form of structural stone. Using precision engineering, each tread is drilled to accommodate steel tendons which are tensioned after installation. This process places the stone permanently into compression, creating a staircase that is both structurally robust and visually striking. The result is a free-standing stone stair that appears to float, combining architectural ambition with proven engineering.

What Makes Post-Tensioned Stairs Different

Traditional cantilevered stone stairs rely on embedment into a load-bearing wall. While effective, this approach limits the geometry and scale of the staircase. Post-tensioned staircases, by contrast, achieve stability from within the structure itself. By threading high-strength steel through the stone and tensioning it, the staircase becomes a self-supporting entity. This unlocks new design possibilities, from sweeping spirals to slender straight flights, all executed in solid stone.

Benefits of Post-Tensioned Stone

Post-tensioned staircases combine architectural beauty with technical performance.. They can be designed as free-standing statements in large atriums or complex spirals where traditional cantilevered options would not be viable. The use of post-tensioning also reduces visible support elements, creating the impression of weightless stone while ensuring long-term durability.

Design and Technical Considerations

Selecting the right stone is critical. Dense limestones, granites, and other fine-grained materials are typically chosen for their compressive strength. Each project begins with close collaboration between our designers, engineers, and installation teams. 3D modelling, structural analysis, and detailed planning ensure that anchorages, joints, and tendons are fully coordinated.
There are a series of other important technical aspects and details which are all carefully considered and solved by design including: steel tendon geometry & curvature; tread interlock details; attachment bracketry; stressing and grouting specialists; load testing; temporary build frame.

Our Approach

AF Jones offers a complete service, from initial feasibility studies to final installation. Our team can advise on suitable stone types, structural detailing, and budget implications at concept stage. Fabrication takes place in our workshops, where we have built full-scale mock-ups to demonstrate structural behaviour and finish quality. Installation is carried out by our own specialist teams, supported with temporary works until the staircase is fully tensioned and secure. Quality control, safety, and compliance with building regulations are built into every step of the process.

Why AF Jones

We bring together centuries of stone craftsmanship with modern engineering expertise. Our experience in delivering both cantilevered and post-tensioned stone staircases sets us apart. By combining traditional skills with advanced technology, we can offer clients staircases that are both structurally assured and architecturally exceptional.

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Next Steps

If you are considering a post-tensioned stone staircase, we recommend early consultation. Our team can provide guidance on design options, feasibility, and cost, as well as prepare workshop mock-ups to give certainty before site installation. Contact us to discuss your project or arrange a visit to view a mock-up in progress.