Graphical Construction Glossary >> stairs. >> general >> Spiral Stairs

Spiral Stairs

A circular staircase, the treads consisting of winders only. It takes the form of a helix and is quite often called a helical stair.

The stair above is of a type that was and still is built very cheaply and marketed in a manner that may make it attractive. However my personal opinion is that although these stairs may be just the thing for ascending a medieval bell tower (see the previous page), or getting workmen into hard to get at places, they have no place in modern residential design. An architect or designer who uses one of these where a standard flight can be used is not doing his job! Please note these remarks are confined to the small spiral stairs that rotate around a small centre column.

Below is a table for calculating the rise, going and slope requirements for stairs with winders like the stair above. It is detailed in the BCA 2008 edition. It is provided here as a guide for the design of these types of stairs around a central pole and also for what I call helical stairs that have a circular stair well, IE. they have a wider radius.

The underside of a wide helical stair out of all steel construction. Seen at Greenwich Observatory, London UK.

As soon as the radius of the spiral increases and with it the width of the stairway then unlike the small and dangerous spiral above, it has the potential to become a thing of beauty.

I prefer the name Helical Stair for this type of stair.

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"What can be added to the happiness of a man who is in health, out of debt, and has a clear conscience?
Adam Smith 1723-1790

"When we build, let us think that we build for ever."John Ruskin 1819-1900