How to Add a Hardwood Spiral Staircase

Prep and Installation

• 1

  Measure from the higher floor to the lower floor of the stairwell opening. Measure the length and width of the well. Send these measurements to the stair manufacturer.

• 2

  Tack two strings from one corner of the opening to the other. Drop a plumb bob to the lower floor, starting from where the strings intersect. Mark the spot on the floor.

• 3

  Make an outline on the floor, if you do not have a stairwell opening. Draw four lines at the stairway location. Make the length of each line equal to the diameter of your stairs. Find the center of this square by tacking string lines at the corners. Place a mark on the floor where the two string lines meet.

• 4

  Screw the base plate to the floor at the center mark.

• 5

  Thread the center pole into the base plate. Place any accompanying hardware, such as a base-plate cover, over the pole. Let it slide down to the bottom.

• 6

  Place a wooden tread support block over the center pole. Slide any accompanying hardware, such as washers and nuts, down the pole according to the manufacturer's instructions. Partially tighten the nut with a wrench so the block remains stable.

• 7

  Drop the bottom tread over the center pole. Adjust its position as indicated by the manufacturer's instructions. Remove the tread, ensuring the block remains stable. Tighten the nut firmly. Drop the tread back over the center pole.

• 8

  Attach the first baluster along with its base plate into the hole at the side of the tread. Fasten screws into the pre-drilled holes.

• 9

  Lower the next block, followed by its hardware, over the pole. Drop the nut over the center pole last. Fasten the next spindle to the other side of the tread.

• 10

  Add the next tread and the next spindles with the first ones. Continue to add treads and spindles until you reach the top of the staircase.

• 11

  Add the landing plate to the pole after all the balusters have been installed. Place the washers over the center pole. Place the nut over the center pole. Tighten the nut securely.

Railings

• 12

  Fasten the landing railing post to the center pole with the accompanying hardware. Nail the top and bottom railings to the wall with finish nails. Fit the balusters into the landing holes and the groove under the railings.

• 13

  Place the first section of the handrail in position over the balusters at the top of the stairs. Have a helper hold the second section in position while you fasten the two sections together with a pre-installed bolt and nut.

• 14

  Have the helper hold the second section in place as you fasten the last section of the railing with the bolt and nut. Ensure that the spindles fit into the grooves under the railing, and fasten with one finish nail.