What is the minimum number of stringers needed for each run of stairs?

The minimum number of stringers needed for each run of stairs is generally determined by the width of the stairway and ensuring adequate support for the treads. Standard practice typically requires at least three stringers for stairs that are wider than a certain dimension, often 36 inches. This configuration provides sufficient strength and stability to the stairs by evenly distributing the weight across the stringers.

Having three stringers helps in preventing sagging and ensures that the stair treads are supported properly, enhancing safety for users. In wider staircases, additional stringers may be necessary, but having at least three is a common requirement to maintain structural integrity. While some applications might allow for fewer stringers under specific circumstances, adhering to the guideline of three stringers is the standard in construction to meet safety codes and building regulations.