Find out how to build deck stairs. Use the stair calculator on decks.com to figure out the number of stairs and the rise and run of each and every person step. View as expert deck builders layout, cut, and attach stair stringers . Get useful suggestions on how to finish the treads and risers to obtain an appealing and effectively constructed staircase. Stair Specifications: IRC code needs stairs need to be at least 36 wide. A 3 x 3 landing area is needed at the bottom of all stairs. In most circumstances flat ground can qualify as a landing. The maximum stair rise is 7-three/4. The minimum recommended rise is 4. The minimum tread depth is ten. The largest tread width or riser height shall not exceed the smallest by a lot more than three/8. Stairs ought to provide a minimum of six-eight headroom clearance and shall be illuminated at the top landing.