What is the maximum run allowed for private stair treads?

The maximum run allowed for private stair treads is indeed 355 mm. This dimension complies with the building codes that dictate the minimum requirements for safety and usability in private staircases.

The rationale for having a maximum run of 355 mm is to ensure that users can comfortably place their feet on the treads while ascending or descending the stairs. A run that is too short would require users to navigate the stairs using less foot space, increasing the risk of slipping or misstepping. Conversely, a longer run can enhance safety and is especially important in residential settings where users may be wearing various types of footwear that might affect their balance or footing.

This standard helps architects and builders design staircases that align with safety regulations, promoting accessibility and ease of use, which are critical factors in any architectural design concerning stairs.