Pull out any carpeting on the stairs, roll it up and set it aside. Depending on its method of installation, you may be required to remove the staples that secure it in place, or scrape the adhesive underneath. Clean the stairs with soapy water and allow to dry. Fill out any low spots or dips in the treads with floor-leveling compound.
Measure the depth and width of a stair tread and riser. To determine how many hardwood boards you will need to cover the tread, divide the stair width by the width of a board. Repeat the process on the stairs riser so you know how many boards you need for each step.
Measure the width of a bull-nose board to determine the gap you need to leave in front of the tread. Although bull-nose boards add a decorative touch to the stairs, you can skip this step if you want plain edges along the front.
Cut the hardwood boards to fit over the lowermost stair’s tread and riser, with a circular saw. Dry-fit the boards on the riser and tread to ensure they form a snug fit, or trim as required. Remove the boards and set these next to the stair.
Slice off the tongue from a hardwood board for the lowermost riser. Spread adhesive over its back and set it on the riser, with its lower edge resting flush on the floor. Apply a bead of adhesive over the grooved edge of this board.
Spread adhesive over the back and tongue of a board. Slide the tongue of this board into the grooved edge of the previous board to lock them together and cover the riser. Continue this process until this riser is completely covered.
Spread adhesive over the back of a board and set it on the tread above the covered riser. Align this board so its grooved edge falls flush against the base of the riser it touches at the back of the stair. Spread adhesive over the back and grooved edge of another board and set it over the tread, with its glued edge locking into the tongue of the previous board.
Repeat this process for laying boards until you completely cover the tread, or leave a gap if you want to install a bull-nose plank.
Spread adhesive over the back of a bull-nose board and lay it over the exposed edge of the edge along the front of the stair. Slide this board so its grooved edge locks into the tongue of the previous plank.
Install the remaining hardwood planks over the risers and treads of the remaining stairs along the stairway.