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Design of ultra-thin UHPC stairs


In singular buildings, stairs can be much more than an element connecting two storeys. They can be a piece of art too. This requires a design adapted to the performance of each material (steel, wood, concrete, …). RDC proposes UHPC as a great option to reach slender and harmonic stairs, which are at the same time functional and without vibrations.

Why to use UHPC?

UHPC allows to go beyond the traditional design of stairs. Instead of using the steel rebars for the reinforcement of ordinary concrete, fibers can provide all the tensile capacity necessary in the design. This reduces the covers and allows to design elements with thickness between 4 and 8 cm. This implies that the weight is more than 50% lower than the weight of an ordinary concrete stair, having a slenderer element and applying lower loads to the rest of the structure. RDC has designed already helical, spiral, and straight UHPC stairs, all of them produced by PREFFOR and installed successfully in singular houses.


  • Slender and tailored designs.
  • Minimum loads transferred to the structure.
  • As they are light, transport and commissioning is easy.


  • 7 different UHPC stairs built in Spain (helical, spiral, straight, …)

More Projects with UHPC


RDC works closely with the client to evaluate the technical, economical and environmental viability of replacing its current solution by UHPC. A tailored premix of Formex® is proposed to maximize the competitiveness of the new element.



UHPC Applications


RDC helps the client to make real the use of UHPC in the daily industrial production. The team supports in stages as the scale-up of the production, the resolution of bottlenecks and the implementation of the quality control plan.





UHPC (Ultra-High Performance Concrete) is an extremely compact and ductile cementitious composite. Its properties make it perfect for applications where durability or maintenance play a significant role, where a lightweight structure is particularly relevant, or where the slenderness or thickness of piece is is important.


Do you think that UHPC can add value to your business? Share your thoughts with us. We can help you

If you feel that this innovative material can help you to solve a problem that you have, to improve the quality of your product, reduce the maintenance required, minimize the transportation costs, or any other, write us. We will share with you our point of view.