How to Install Prefinished Stair Treads

Measure the length of existing stair tread that hangs over the rise. This piece is referred to as the nose. Mark the nose's length on each stair tread's top surface.

Set up a laser level so it extends across the first step's tread, even with the nose mark you just made. Cut along the laser level with a circular saw to remove the step's nose. Repeat this step with all the steps' noses. If you can't cut the stair nose all the way off with the circular saw, cut off as much as you can, then hit the nose with a hammer to fully remove it.

Scrape away any ridges or uneven cuts along the stair's front edge, where the nose was, with a 1/2-inch wood chisel. Sweep the stairs with a broom to remove all the loose debris.

Measure the first stair rise's height and length. Transfer these measurements to a prefinished rise. Draw a straight line down the rise, along the marks, using a level. Rip the stair rise along the lines with a table saw.

Place the prefinished stair rise against the first stair rise and hold it in place. Measure the stair tread's depth, from the corner where the tread meets the second stair's rise to the prefinished stair rise's front edge.

Transfer the stair tread depth measurement to a prefinished stair tread. Measure from the tread's front edge toward the back edge. Draw a straight line across the tread, along the mark, using a level. Rip the stair tread along the line with a table saw.

Measure the stair tread's width, from the left side to the right side. Divide this measurement in half and subtract this measurement from the prefinished stair tread's right and left edges. Draw two straight lines across the stair tread at these marks, using a level as a straight edge.

Set the prefinished stair tread on a sliding miter saw table face up and cut it along the width lines you drew. Test fit the prefinished stair tread over the existing stair tread. Make any adjustments if necessary.

Squeeze a curvy bead of construction adhesive to the back of the prefinished stair rise. Press the prefinished stair rise over the existing stair rise.

Squeeze a curvy bead of construction adhesive to the existing stair tread's surface. Press the prefinished stair tread over the existing stair tread. Drive four finishing nails, one near each corner, through the prefinished tread, with a pneumatic nail gun, to hold it in place.

Repeat on each of the stairs until you have mounted prefinished treads on each one.