International Compliance Association (ICA) Home Inspector Practice Exam

What is the ideal tread run for stairs?

1. 10"

2. 11"

3. 12"

4. 13"

The correct answer is: 12"

The ideal tread run for stairs is important for safety and comfort. A tread run of 11 inches is generally considered the standard for most residential staircases because it provides adequate depth for footing, minimizing the risk of slipping while ascending or descending. However, a tread run of 12 inches is often preferred in many building codes and design perspectives, as it offers even greater surface area for foot placement, thereby enhancing stability and comfort. A 12-inch tread run accommodates a wider variety of foot sizes and shoe types, contributing to safety, especially for those who may be unsteady. The additional inch can also help those who may have mobility issues. In contrast, a tread run less than 11 inches may make stairs feel steep and could increase the risk of accidents. While 10 inches is on the lower end of the acceptable range and could lead to discomfort or increased risk of misstep, runs larger than 12 inches, like 13 inches, could lead to overly shallow risers in an effort to maintain a comfortable stair angle, which can compromise the overall design and accessibility of the stairs.