What Is the Railing Length of a Spiral Staircase?

Determining the Length

• If you add a new staircase, you must determine the length of the railing. Measure the space between the outside edge of the staircase to the support pole running through the middle of the stairs, which is the radius. You must also measure the distance from the bottom of the first floor to the bottom of the second floor, which gives you the height of the staircase. Multiply the radius of the staircase by Pi and 2 and square the figure. Square the height of the staircase and add it to the last measurement. Find the square foot of the final number, which gives you the length of the staircase.

Considerations

• Once you have a figure in mind, consider adding 1 or 2 inches to the final number. Adding a few inches gives you a slight overhand at the top of the handrail, the base of the handrail or both. The overhang compensates for any decorative elements, such as scroll work or rounded ends. If you purchase a railing with rounded ends, the measurement given is the overall length of the piece. The length covers the staircase, but might stop an inch or more from where you actually want it.

Rectangular Spirals

• A rectangular spiral combines a traditional staircase with a circular design. Instead of having the rounded, serpentine shape, the designer uses rectangles. The finished design has a more angular or geometric shape. When determining railing length, you must measure the span from one rectangle to the next. Each rectangle or set of steps has its own railing that affixes to the staircase. Angled edges put the railings flush against each other.

Warning

• Make all of your measurements and write down each figure. Measure each area multiple times and compare the figures against each other. If you find that you have two different figures for one area, measure again. The same holds true when you use the formula for determining the overall length of the staircase. Forgetting to square even one figure or subtracting instead of adding can seriously change the dimensions.