Over time, wooden stair treads and risers become damaged and need to be replaced. Or you might opt to replace old tread and riser material to match a new type of wood stock. Replace the treads and risers by wedging and prying out the old material with a hammer and pry bar. You'll then trace the old treads and risers onto new material and cut them out.
Place the flat end of a pry bar under the front lip of the top stair tread. Hit the back end of the pry bar with a hammer to wedge it between the stair tread and the riser. Push down on the back end of the pry bar until the stair tread and nails come out completely. Start at the top of the stairs and work your way down.
Bend or pull out nails from the tread, using a hammer. Lay the old tread on the new material and trace along the outer edge with a pencil. Cut out the new tread using an electric saw. Mark the tread with the number "1." Continue marking each tread that you cut, counting up from "1."
Repeat the removal process with tread No. 2 to expose the first riser. Wedge the flat end of the pry bar between the riser and stair stringer and pry it out. Place the old riser on the new material and trace around the outer edge. Cut out the riser using an electric saw and mark it with the number "1." Mark each riser that you remove, counting up from "1" so you know where it belongs when you install the replacement.
Repeat the stair tread and riser removal process, cutting each one as it is removed, until you reach the bottom of the stairs.
Chip or scrape away hardened glue with a chisel and hammer. Remove any leftover nails by either pulling them out with a hammer or cutting them flush with the stair stringer face using wire cutters.
Set the first and second riser in place, starting at the bottom of the stair stringer. Hammer or shoot two or three evenly spaced finish nails through the riser and into each stringer.
Lay the last tread that was cut from the new material onto the stringer to dry fit it. Remove the tread to expose the stair stringers. Cut off the tip of a tube of construction adhesive and break its seal using a nail or another sharp object. Squeeze a 1/2- to 3/4-inch dab of adhesive onto the stair stringers at the point where the tread will be set.
Set the tread back onto the stair stringer and push down to encourage the adhesive to bond between the two surfaces. Shoot or hammer three evenly spaced nails through the face of the tread directly into the stringers below.
Repeat the process of installing the riser first and the tread second until you reach the top of the stairs. Fill in all of the nail holes with wood filler.
You may need to remove the stair trim in order to wedge out the treads and risers. You can do this by slipping the flat end of a pry bar behind the trim and prying it out.
When removing old stair treads and risers, start at one end of the stairs and work your way down. Work your way back up when installing the new treads and risers. This process will reduce your chances of misstepping and falling down the stairs.