First , confirm the size of your spiral staircase
and the spiral diameter is >1000mm, and the common length can be 60”, 66in, 72in,78in)
Once confirming the size of your staircase, the center column size is almost confirmed , and the support to the staircase treads is clear now.
The style is determined by the components of the staircase , we will find that , there is metal spiral staircase , wooden staircase , glass spiral staircase , victorial spiral stairs, and all kinds of custom style.