Key Measurements To Heavenly Stairways - Steven Corley Randel, Architect Two extremes are presented: a very steep stair with 8-in. risers and a gentle stair with 6-in. risers. Critical is the run of the stairs. Clearly shorter risers will require much more space. Most staircases fall somewhere between these two extremes. For example, a staircase with 7-in. risers and 11-in. treads creates a comfortable ascent for most people.