Shopping for Pre-Built Stairs This pre-fabricated circular stair from Challis Stairways (Sandy, Utah) turns about 180 degrees and terminates in a volute. The laminated curved stringers are mitered to fit against the risers. by Bill Penrod We turn out over 10,000 sets of stairs each year from a small shop in Winooski, Vt. Each stair we make is custom-built to match field measurements, but there are really only a few basic types to choose from. For traditional stairs, there are box stairs, which are fully enclosed, and open stairs, which have the stringers partially or fully exposed. For a price, open stairs can be made in a sweeping curve, called a circular stair (not to be confused with a free-standing spiral stair). For a contemporary look, any stair