Stair terminology — in one flight of stairs, the number of treads equals which relationship relative to the number of risers?

Introduction / Context:
Correct stair terminology is vital for setting out safe and comfortable staircases. Two core terms are riser (vertical step height) and tread (horizontal going). Understanding their count relationship helps in layout and quantity estimation for architectural and structural drawings.

Given Data / Assumptions:

• A single flight of stairs runs from one floor level to a landing or to the next floor.
• There is a starting floor at the bottom and a landing/floor at the top.
• The top level is reached by stepping onto the landing, not onto an extra tread beyond the last riser.

Concept / Approach:

In a typical flight, the number of risers equals the number of vertical increments needed to reach the next level. Treads are the horizontal surfaces between risers. Since the upper landing/floor serves as the final horizontal surface, the number of treads is one fewer than the number of risers in that flight.

Step-by-Step Solution:

Verification / Alternative check (if short method exists):

Create a quick sketch: label risers and intervening treads; you will observe one fewer tread than risers from floor to landing.

Why Other Options Are Wrong:

“Risers plus one” double counts the landing; “risers in the flight” ignores the landing; “none of these” is incorrect because a standard relation exists.

Common Pitfalls (misconceptions, mistakes):

Confusing stair runs that include an additional platform or winders; forgetting that the first step may start at floor level (no tread before the first riser).

Final Answer:

risers minus one