Key strengths

  • The structure is more attractive and has more freedom for designing.

  • The stiffness provided in the design avoids vibrations under service.

  • Due to its lightness, its influence on the structure is mínimum.

  • Its construction requires up to 80% less resources than the traditional solutions.

  • As it is made in-situ, it can be installed in difficult access spaces.

Formex® singular stairs


Preffor designs and produces singular stairs tailored for the client requirements. These solutions minimize the volume of resources used for their construction and, at the same time, enhance the architectural value of the building.

The product is adapted for the volume and environment of each location, where very thin straight, curve or accordion staircases can be installed. The color, texture, treads, lights and complements can be adapted for the architect’s taste.

The maximum thickness of the solution ranges, depending on the structure conditions, between 3 and 6 cm.


Escalera Formex Accordion vista desde arriba

Escalera Formex Spiral

Formex® Helical Staircase

Curved ortopolygonal model

Formex® Spiral Staircase

Helical shape. Suitable for small spaces

The tailored design of our Formex® stairs is made by a specific calculation procedure that, considering the tensile capacity of the cementitious composite and the ductility of the structure.

The result is a singular staircase with a extreme lightness and resistance adapted to the space and characteristics of the house. While allowing the vertical access between the different levels of the building becomes the absolute protagonist of the built space.


Adapted, “tailored”


between 3 and 6 centimeters

Supporting points

Reduced: In extremes (ground supports) and intermediate points (wall anchors)