Stapling carpet onto stairs is only one small part of the process necessary to lay carpet or a stair runner on a set of stairs. Tools other than a set of staples and a staple gun are necessary in order to permanently install a carpet on stairs; however, the individual process of stapling the carpet requires a special technique to prevent sagging carpet on the rise of stairs and to prevent pain or foot injury from protruding staples.
Use a single pre-cut and pre-measured carpet roll for straight stairs so you can drape the carpet over the ends of the stairs, covering the stairs completely and ensuring that the carpet stays in place. You may also choose to install carpet on just the treads of each step.
Begin laying and attaching the carpet at the top of the stairs and work toward the bottom step. Attach the carpet at the top of the stairs and at the back of each tread and bottom of each rise with a tackless strip; this holds the carpet into place, attaching it to the stairs in places where staples should not be placed.
Stretch the carpet out and over the first step. Pull the carpet taut and hook into the tackless strip at the bottom of the first rise from the top of the stairs.
Place the staple gun as close to the edge of the carpet as possible along the outer edges of the carpeting on the rise. Pull back the fibres of the carpet, getting the staple gun end as close to the floor as possible through the carpet.
Pull the trigger on the staple gun and release the staple into the carpeting. Lift the staple gun and check to see if the staple is visible when the carpet falls back into place. If you can see or easily feel the staple, you will need to retract the staple and replace it with another staple. Continue to place staples two-inches apart along the outer edges of the carpeting on the rise and tread of the stairs and never through the middle of the steps.
Use a nail set to push staples further into the carpet and completely hide the staples from visibility and from touch detection. Simply place the nail set at the ends of the staples and hammer until the nail set is no longer visible or felt.