Space requirements: For spirals coming up through a stairwell keep in mind the stairwell size required for the spiral you want. These sizes are usually given as "finished" dimensions. We will need to take into account the size of the stairwell rough opening as well as the thickness of the material (drywall, paneling, etc.) that will cover the top floor framing (figure 10).
Figure 10.
Examples of framing "Rough Opening"
vs
Stairwell "Finished Opening"
Spiral space required at loft edges:
Spirals that go up to a loft edge will require on the lower floor a circular
area of the same diameter as the stair (figure 11). This circle
should be positioned according to how far out from the loft edge, or how
far under the edge, you plan to install the spiral. The spiral requires
the same space as a cylinder rising above the circle. For more visual
planning you can cut a circle out of taped cardboard or newspaper and
move this around accordingly on the lower floor.
Figure 11.
Determining space required for a spiral to a loft edge
