How to Create Stairs in FreeCAD

This guide explains how to generate and customize parametric stairs for an architectural building model in FreeCAD. By utilizing the dedicated Stairs tool found in the BIM or Arch Workbench, you can quickly build straight, multi-flight, or landing-based staircases. The following steps cover workbench setup, initial stair creation, parameter modification for accurate treads and risers, and placement within your building structure.

1. Switch to the BIM or Arch Workbench

Open your building project in FreeCAD. In the workbench dropdown menu located on the top toolbar, select either the BIM or Arch Workbench (in FreeCAD 0.21 and later, these tools are consolidated under the BIM workbench).

2. Launch the Stairs Tool

You can generate stairs either from scratch or from a 2D guideline:

  • Direct Generation: Ensure nothing is selected in the 3D view, then click the Stairs tool icon in the toolbar (or navigate to BIM > Stairs). FreeCAD will insert a default straight staircase at the origin coordinates (0, 0, 0).
  • Using a 2D Path: Draw a baseline (Draft Wire or Line) representing the flight or boundary of your staircase. Select the line in the Tree view, then click the Stairs tool to generate a flight along that path.

3. Configure Tread and Riser Dimensions

Select the newly created Stairs object in the Tree view and switch to the Data tab in the Property panel (bottom-left):

  • Height: Set the total vertical rise to match your floor-to-floor height.
  • Length: Define the total horizontal run of the stair flight.
  • Width: Specify the width of the steps (e.g., 900 mm to 1200 mm for standard residential stairs).
  • Number of Steps: Set the count of steps. FreeCAD will automatically recalculate the Riser Height and Tread Depth to distribute the dimensions evenly across the specified total height and length.

4. Customize Stair Structure and Landings

Under the same Data tab, adjust structural details to match your construction method:

  • Structure Type: Choose between None, Massive (solid concrete), Overlapping (stepped underside), or Sawtooth to define the underside geometry.
  • Structure Thickness: Specify the thickness of the supporting slab beneath the treads.
  • Stringers: Enable left or right stringers (set Stringer property to True) and adjust their width and offset if designing an open-timber or steel staircase.
  • Landings: If creating an L-shaped or U-shaped configuration, adjust the Landings property to specify after which step a flat landing platform should appear.

5. Position and Group the Stairs

Move the stairs to the correct location in your model:

  1. Select the Stairs object and expand the Placement property in the Data tab.
  2. Adjust the Position coordinates (\(X\), \(Y\), and \(Z\)) or use the Draft Move tool to align the base of the staircase with the ground slab.
  3. In the Tree view, drag and drop the Stairs object into the relevant Floor or Building container to keep your IFC building hierarchy organized.