Follow these steps carefully to prepare your stairway for carpet installation. First, remove any old carpeting from the stairs. Use pliers to pull up any carpet tacks left in the wood, being careful not to splinter it. Vacuum the stairway thoroughly.
Measure the stairs carefully for the new carpet. On straight stairs, stretch a measuring tape or rule around one entire stair, starting at the inside edge of the tread and moving over the outside of the tread and down along the riser below it to the top of the next tread. Add 1 inch and multiply by the number of steps, not counting the last riser to the top landing. Measure any landings and add these measurements to the tread figure; add 1 inch to be turned in at the ends. Divide the total by 36 to determine the number of yards of carpet runner you need. You'll need roughly the same length of padding; the exact length used will be less because the padding doesn't cover the stair risers completely.
To measure for carpeting on a winding stairway, first measure straight stairs and landings as above. Then measure each wedge-shaped or turning step at the widest point the carpet will cover, and add 1 inch. Measure each wedge-shaped step separately. To determine the number of yards of carpet runner and padding you need, add all the stair measurements together; add 1 inch for top and bottom edges and divide by 36.
Carpet runner is sold in standard 27-inch and 36-inch widths; buy the width that best fits your stairway. Don't try to use carpeting left over from a room installation -- cut-to-fit carpet pieces have to be turned under at the edges all along the stairs, and that's tricky. Buy 6 inches or so more than you think you need, just to be safe.
Choose a high-quality heavy rubber or felt stair carpet padding; it doesn't pay to economize here. Ask the carpet dealer to figure the amount of padding and the number of tackless fastening strips you'll need -- the strips will have to cover roughly twice the width of the stairway for each step.
Finally, rent a knee kicker from the carpet dealer. The kicker is used to stretch the carpeting tightly onto the fastening strips at each riser-tread intersection, producing a more stable runner than hand-stretching techniques.
Begin the installation by nailing fastening strips at each riser-tread corner; wear work gloves.
Measure the width of the stairway and subtract the part that will be covered by the carpet runner; divide by 2. This is the number of inches at each side of the stairs that won't be covered. Measure in this distance from one side of the stairway at the base of each riser and the inside of each tread; mark each of these points with chalk or pencil. Then measure in the same way from the other side of the stairs. Measure each stair across from mark to mark to make sure you've measured accurately; the carpet runner will be centered on these marks.
Cut the strips to the width of the runner with a small handsaw. On each stair, nail a strip centered on the riser, teeth pointing down, 3/4-inch above the surface of the tread below it; use a 3/4-inch-thick piece of scrap wood to hold the strip in place as you nail it. Nail another strip centered on the tread, teeth pointing in to the riser above it, 5/8 inch out from the riser. You'll end up with an open V of fastening strips at the back of each stair, straight or wedge shaped, with one strip near the floor at the bottom of the lowest riser and one at the back of the top tread. Don't nail a strip onto the top riser.
After nailing the fastening strips, measure and mark the carpet padding. Measure the padding to the width of the carpet runner, less about 1/4 inch so that it will be very slightly recessed under the carpet edge at each side. With a heavy scissors, cut a strip of padding to fit over each stair tread, long enough to wrap from the tread fastening strip around the tread and down about 2 or 3 inches onto the tread below it. Make a paper pattern to cut the padding for each wedge-shaped step; the padding must cover the tread, round the edge, and wrap over onto the riser below it.
Install the padding with staples. Center a trimmed piece of padding, waffle-patterned side up, on each tread, with its end butted against the fastening strip at the back of the tread. Staple the end of the padding to the tread, using a staple gun to set staples diagonally every 2 inches along the fastening strip. Stretch the other end of the padding out over the tread and down onto the riser below it; holding it evenly stretched, staple it into place. Use the paper pattern to cut padding for wedge-shaped stairs, and fasten the padding the same way.
Finally, unroll the carpet runner and drape it over the stairway, with the nap or pile leaning out and down from top to bottom. Winding stairways should be treated as straight flights interrupted by wedge-shaped steps; lay the carpeting out over the bottom straight flight and up to the first wedge step. Pull the carpet runner into place from the bottom up, making sure that the nap or pile lies in the right direction (down) and that the carpet is positioned straight over the fastening strips and between the chalked centering marks on the stairs. Even a small skew at the bottom can magnify noticeably by the top of the stairway, so adjust the runner carefully.
With the fastening strips and padding in place, use the next page to learn how to secure the carpeting to the stairway.
For more information related to carpet installation:
- How to Install Carpeting: Need to carpet an entire room? Learn how to install wall-to-wall carpeting with this article.
- Carpet-Cleaning Tips: Whether due to spills and stains or just a lot of traffic, carpet gets dirty over time. Use these tips to keep your carpeting looking its best.
- How to Repair Floors: Squeaks and cracks can be signs of problems with your floor. Find out how to make the repairs you need.