Design & Support Considerations
Design by Kallisto
The layout and positioning of a stair has significant impacts on the design of a dwelling. To enable us to provide an accurate and well detailed quotation, clients will need to employ an Architect to produce drawings showing the layout of the stairs within the development. These drawings must also comply with the requirements of the Building Regulations Approved Document K and BS 5395-2 1984 Helical and Spiral Stairs.
Our in-house design team will produce initial sketches included with our quotation, detailing the layout of the precast units with indications as to how they will need to be supported during installation. Upon confirmation of order, detailed CAD drawings will be produced with extensive information detailing the staircase design. The design of the supporting structure is the responsibility of the Client’s Structural Engineer.
Kallisto Bespoke Concrete Staircase Design Examples
How To Support Precast Concrete Storey-Height Curved, Helical or
Dog-Leg/Winder Staircase Flights & Bespoke Concrete Landings
A range of supporting variations are available when considering a curved, helical or winding precast concrete stair. Although the design of the supporting structure is the responsibility of your Structural Engineer, we are able to provide accurate and professional advice and information on the effective methods of supporting your staircase. As the Centre of Gravity of a curved flight is outside the line joining the centres of support, the flight will pivot about this axis as detailed in the illustrations provided.
In addition to our precast stairs, we are also able to provide bespoke precast concrete landings to incorporate within the load bearing structure. As a luxurious accompaniment to any of our stairs, our custom-made curved landings match the sweeping geometries of the stairs providing both aesthetics and additional structural rigidity. Intermediate or rest landings should have a plan area of no less than two consecutive treads or subtend an angle of 45° at the geometric centre on plan - whichever is the greater.
Intermediate Support - The Centre of Gravity is within the lines joining support centres
Moment Resisting Connections - The stair is tied at both top and bottom 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.
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. Please note that the precast element will finish a minimum of 200mm from the adjacent nosing.