Remove any carpet or other floor covering from the stairs, if applicable, to expose the wood treads and riser boards.
Remove the stair treads. Inspect the tread surface at each edge and the middle for the nail locations. Use a nail punch and hammer to drive each tread nail downward through the tread into the support boards beneath to release the tread.
Remove the riser boards. As with the treads, inspect the vertical riser boards at each edge and the middle for the nail locations. Use a nail punch and hammer to drive each nail through the riser board into the support boards beneath to release the board.
Detach the stair stringers, also referred to as stair "horses" or "bucks." from the upper landing. Use a pry bar to remove any support blocking or brackets securing the ends of the stringers to the upper landing framing. Depending on the width of the stairs, there can be as few as two stringers and as many as five for stairs exceeding 48-inches wide.
Remove the stair stringers. Remove the support blocking or brackets securing the ends of the stringers to the lower floor framing to detach each.