Ceiling height. The distance from the highest tread below a ceiling should be at least 80 inches, or 6 feet, 8 inches. As a 6-foot-3-inch man who lives in Philadelphia and spends a lot of time in historic homes, I can tell you that this rule wasn't regularly followed in the time before building codes. Don't make the same mistake. On the way up, people will bump their heads if the ceiling is too low. On the way down, it's hard to judge ceiling height, so people will duck if it looks too close. Give people plenty of room whenever possible. A stair is a dangerous place for a fall, and the codes governing stairs are designed to prevent just that.