Whatever happened to spiral staircases modern houses used to have in the 70's?
the rise (height of each step) needs to be greater than is typically allowed by building codes, you also need 80 inches of head clearance from the line of the tread nosing, and a minimum depth of tread from nosing to nosing these requirements are impossible to get from a small diameter spiral staircase and getting a special allowance for one from the building department is nearly impossible I had a client who wanted one outside for a single story rooftop garden and the building department wouldn't even consider it
