Measure the horizontal distance from the front edge of the first riser to the front edge of the last riser. This measurement, combined with the tread depth, will determine the overall horizontal space the staircase will occupy.
Step 4 · Measure the Total Run
Measure the horizontal distance from the front edge of the first riser to the front edge of the last riser. This measurement, combined with the tread depth, will determine the overall horizontal space the staircase will occupy.