To prepare for the stairs to be finished, cut back the lip on the existing treads and thoroughly clean the stairs with a vacuum.
Next use a tape measure (Image 1) and mark where cuts need to be made on each tread and riser, cutting at the marks with a miter saw (Image 2).
To get an exact edge, use a grinder (Image 3).
Apply a construction adhesive on the back of the first riser (Image 1). Position it in place (Image 2), and only after it’s in the correct position, nail it into place with a finish nailer (Image 3).
Repeat the process with each step. Use a rubber mallet to position the stairs in their exact spot, making sure the stair is plumb and even with a box level (Image 1), using shims where necessary (Image 2).
After all the stairs are in place, wait for the glue to dry and lightly sands and cleans the stairs with a broom and a shop vac. Finally apply a stain and polyurethane finish.