Staircase Formers

Staircase Formers

Constructing cast in-situ concrete helical and spiral staircases can prove challenging without the use of the appropriate formwork. Bespoke formers can allow the complex geometry of the staircase to be created, whilst also achieving a soffit finish of sufficient quality to be left exposed.

Each former is designed to meet the specific requirements of the project, including the size, shape, finish and number of re-uses required. Based upon this information our designers will select the most appropriate material for each former and create a 3D CAD model for approval before commencing manufacture.


  • Manufactured to meet project specific requirements
  • Available in a wide range of materials
  • CNC machined for consistent, tolerance controlled surfaces
  • Re-usable where staircases or flights between floors of the same size, shape and profile are required
  • Can be used in conjunction with proprietary supporting falsework
  • Basic, Ordinary, Plain & Special Finishes achievable*

*Please refer to National Structural Concrete Specification (NSCS) Edition 4 guidance available below.


Used for the construction of cast in-situ reinforced concrete helical and spiral staircase soffits with either complex or non-standard geometries, profiles and sizes.


Staircase Formers

When developing a helical or spiral staircase former design, the following factors should be considered in addition to reviewing any CAD drawings, 3D models, specifications etc that are available:

  • Dimensions, geometry and features
  • Type of soffit profile (Level, Sloping or True)
  • Required concrete finish (Basic, Ordinary, Plain or Special)
  • Proposed number of uses – single or multiple
  • Loadings – specifically relating to the proposed concrete pour depths
  • External structural support method
  • Delivery method, unloading requirements and access restrictions
  • Positioning, installation and sequence of construction
  • Striking, removal and re-use or disposal

Once the project requirements have been confirmed, a conceptual design can be completed along with provision of a quotation confirming proposed material type, features, quantities, manufacturing lead time and costs.

Materials & Finishes

Staircase Formers

Typically, Cordek staircase soffit formers are manufactured from one of the following material types:

  • Filcor Expanded Polystyrene (EPS)
  • Filcor EPS with Correx skin
  • Filcor EPS with ABS skin
  • Filcor EPS with Sheet Fibreglass skin
  • Filcor EPS with a spray applied Polyurea skin
  • Glass Reinforced Plastic (GRP)

One of the factors determining the most appropriate material used to manufacture a staircase soffit former is the required concrete finish. Further information in relation to the classification of concrete finishes can be found within the National Structural Concrete Specification (NSCS) Edition 4 guidance, a copy of which can be downloaded from the Certification, Guidance and Approval section below.


Staircase Formers

Once approved, the agreed 3D CAD Model will be converted into CAM data allowing accurate manufacture of the staircase soffit former via CNC hot wire cutting and / or 5-axis routing dependant on factors such as material type, complexity of shape / profile and required tolerances.

In some instances, due to the required dimensions of the former, it may comprise of a number of individual units that require assembly on site. This can prove advantageous in certain applications, such as those with limited access space or where positioning on supporting falsework is required.

In cases such as these, design features and installation guidance can be provided to minimise grout loss at joint locations and improve the concrete finish achieved.


Data Sheets

Product Issue Date Version Size Download
Filcor Data Sheet 03/2021 8 405.9 KB

Standard Details

Product Issue Date Version Size Download

MSDS Data Sheets

Product Issue Date Version Size Download
Expanded Polystyrene MSDS 06/2017 5 137.3 KB

Certification, Approval & Guidance

Product Issue Date Version Size Download
National Structural Concrete Specification (NSCS) Edition 4 1.2 MB


Product Issue Date Version Size Download
Construction Solutions 01/2020 2 6.6 MB

NBS Clauses

Our NBS Clauses are hosted on the external website - view NBS Clauses

BIM Library

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Name IFC Size IFC Download Revit Size Revit Download
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Contact our Project Design Team to discuss your requirements

ProjectDesign@cordek.com01403 799600