Design & Support Considerations

Curved Concrete Stair Design & Support Considerations

Expertly Engineered Precast Stair Design, Tailored to your Structure.

At Kallisto, every staircase is as individual as the property it inhabits. The layout and positioning of a curved concrete stair have a critical impact on both the aesthetic and structural flow of a building. To ensure accuracy in design and quotation, we require that clients engage a qualified architect to provide detailed drawings showing the stair layout within the development.

These drawings must comply with:

Building Regulations Approved Document K
BS 5395-2:1984 – Helical and Spiral Stair Design

Our in-house design team will create initial layout sketches as part of your quotation, including indicative support details. Once your order is confirmed, we supply detailed CAD drawings that outline the full geometry, dimensions, and support strategy for your bespoke precast concrete staircase.

The design of the staircase’s supporting structure is the responsibility of the client’s appointed Structural Engineer.

Designing Support for Precast Concrete Curved, Helical, or Winder Staircases

A variety of support solutions are available when designing curved, helical, or winder precast concrete staircases. While the structural support design remains the responsibility of your appointed Structural Engineer, Kallisto is pleased to offer expert guidance and technical insight into the most effective methods of supporting our stair units.

Due to the nature of curved flights, where the centre of gravity lies outside the axis connecting the main support points, the staircase will exert a pivoting force about this axis. This rotational behaviour must be carefully considered in the supporting structure. Diagrams illustrating this load path and pivot action are available upon request.

In addition to our stair flights, we also offer bespoke precast concrete landings that can be integrated into the load-bearing structure. Designed to mirror the staircase’s form, these custom landings enhance both aesthetic continuity and structural stability, making them a luxurious and practical complement.

For optimal performance and compliance:

Intermediate or rest landings must have aplan area no smaller than two consecutive treads, or

Subtend an angle of at least 45° at the geometric centre of the stair plan, whichever provides the greater area.

Support Solutions

Intermediate Supports

We are able to provide intermediate supporting variations in the form of either a projecting precast concrete corbel cast as part of the flight (otherwise known as a nib), or a steel supporting bracket. Both methods are either fixed or built into the loadbearing structure as detailed by your Structural Engineer.

Moment Connections

Our precast staircase flights can be manufactured to include projecting steel reinforcement which is cast into an insitu concrete topping during the installation process. Please note that the flight will need temporary propping on site until the concrete has completely matured and cured.

Support At Flight Ends

Moment connections at ground floor level may be achieved by resin fixing reinforcement into a concrete pad and infilling the voids through the bottom tread with non-shrink grout. Flights without moment connections merely rest on the supporting structure. Flights may be manufactured with cast in angles which will rest on the precast or insitu concrete upper floor slab. Alternatively, the cast in angles can be bolted or welded to a steel beam. Please note that the precast element will finish a minimum of 200mm from the adjacent nosing.