What is the minimum tread thickness?

What is the minimum tread thickness?

• A. 25 mm
• B. 20 mm
• C. 30 mm
• D. 22 mm

Answer: (A)

Stair treads have to be thick enough to carry foot traffic safely and withstand wear without bending or cracking, while also leaving room for finishing, fasteners, and any nosing. Building standards set a not-less-than thickness for timber treads to achieve these goals, and that value is 25 millimeters. A thinner tread, like 20 or 22 millimeters, could be prone to wear-through or structural stress; a thicker one, such as 30 millimeters, is acceptable but not required by the minimum standard. So the minimum thickness is 25 mm.

Stair treads have to be thick enough to carry foot traffic safely and withstand wear without bending or cracking, while also leaving room for finishing, fasteners, and any nosing. Building standards set a not-less-than thickness for timber treads to achieve these goals, and that value is 25 millimeters. A thinner tread, like 20 or 22 millimeters, could be prone to wear-through or structural stress; a thicker one, such as 30 millimeters, is acceptable but not required by the minimum standard. So the minimum thickness is 25 mm.