how many stairs for 9/11

The typical number of stairs to reach a 9-foot ceiling height is between 15 to 17 steps. This is based on the average vertical height the stairs need to cover, considering the ceiling height plus additional thickness from drywall, floor joists, and flooring materials. The average height for each step (riser) is usually around 7 to 7.75 inches. A 9-foot ceiling typically requires more steps than an 8-foot ceiling (which has 13 to 15 steps) but fewer than a 10-foot ceiling (which requires 17 to 19 steps).