Bullnose stair treads have a rounded-over edge that protrudes from the staircase. This allows a carpet installer to wrap the carpet over the edge to create a tight fit between the stair and the carpet. This provides a solution for those who do not want to "waterfall" carpet or have loosefitting carpet over the stair treads. Installing a bullnose stair tread is relatively straightforward.
Remove the carpet from the stair treads, if necessary, using a pry bar.
Place a pry bar between the bottom of the original stair tread and where the edge of the stair tread nails to the staircase framing. Pull the old stair tread off the staircase framing and remove any nails left behind with a claw hammer. If you are installing the bullnose stair tread onto a new staircase framing, skip the first two steps.
Measure the width of the stairwell with a tape measure and write down the number. Measure the depth needed for the stair tread, placing the tip of the tape measure against the back of the staircase framing and extending it across the flat base of the staircase where you will nail the tread down. Add 1 inch to the measurement for overhang. Write this number down.
Cut a bullnose tread to the appropriate length and width on a table saw.
Drill several 1/16-inch pilot holes through the top of the bullnose tread approximately ½ inch from the edge on each end of the tread.
Place the bullnose tread onto the staircase and secure the tread to the staircase with nails or screws and a hammer or drill.