How to Carpet a Spiral Stair Case

Spiral staircases have been an architectural phenomenon since medieval designers built them into castle turrets -- while you may not have to worry about castle crashers storming your loft apartment, interior decoration is another matter entirely.
Spiral staircases don't accept typical pre-cut stair runners.Spiral staircases don't accept typical pre-cut stair runners.
Carpeting your spiral staircase may pose a challenge in itself because unlike with traditional staircases, spiral staircases are typically composed of open-backed steps that do not have risers between them. This means that instead of using a typical stair runner, you have to measure and cut individual carpet pads for each step.

Step 1

Measure the size and shape of each step. Though the steps have slight curves, measure a straight line from the top right corner to the top left corner. Then measure the horizontal distance between the bottom corners. Measure the vertical distances between the corners on the left and right sides. Despite the curvature of the step, the step should be the same width from top to bottom.

Step 2

Use your tape measure to determine how much space you want on either side of the carpet when it is on your stairs. Subtract this measurement from the measurement for your step width, then use a sharp utility knife to cut out a piece of carpet in the size of your step. Divide the difference between the step width and the carpet width by two, then measure in from either side of the step by that amount and mark it with a pencil -- this is where the carpet lines up.

Step 3

Place your cut-out piece of carpet on the step. Unlike the step, which has curves, the cutout should have sharp angles. Flip the carpet over so that the bottom faces up, and use a marker to trace the curvature of the step onto the carpet. Cut along this line with your utility knife to make a carpet cutout that lines up with the curvature of the step.

Step 4

Lay your carpet cutout on top of a piece of carpet pad and trace the outline. Remove the cutout, then measure 1 inch in from all sides and draw new lines. The result should be an outline that is the same shape as the cutout, but 1 inch smaller on every side.

Step 5

Center the carpet pad on the step and staple it in place with a staple gun. "This Old House" recommends using 9/16-inch staples every 3 inches.

Step 6

Center your carpet cutout over the carpet pad and the step. Staple it in place along the edges, stapling into the step, not the carpet pad. Repeat this process for every step in your staircase.

Things You Will Need

  • Carpeting (varies)
  • Carpet pads
  • Tape measure
  • Marker
  • Utility knife
  • Staple gun and staples

Tips

  • Most spiral staircases have a uniform size for each step, meaning that you only have to measure one step to have accurate dimensions for every step. To determine if this applies to your staircase, measure one step and then cut your carpet for it. Place this carpet on each step to see if it fits -- if it does, use its dimensions as a template.
  • If your stairs are made of metal or a similarly strong material that will not accept staples, consult your manufacturer's instructions -- staircases like these may have special pre-drilled openings and instructions designed to accommodate carpeting.
  • When choosing your carpet, pick something with small, tight patterns -- this is easier on the eyes that big, bold designs. Avoid designs with vertical designs, as they do not line up on spiral staircases.

About the Author

Tom Ryan is a freelance writer, editor and English tutor. He graduated from the University of Pittsburgh with a degree in English writing, and has also worked as an arts and entertainment reporter with "The Pitt News" and a public relations and advertising copywriter with the Carnegie Library of Pittsburgh.