A stair tread is the horizontal surface of a stair step that you place your foot on when walking up or down a staircase. Together with the riser (the vertical part), the tread forms the complete stair step. The tread is the part of the staircase that receives the most wear and must be designed for both safety and comfort.
Application
The stair tread is a critical component in staircase design and construction. When calculating a safe and comfortable staircase, the tread depth is always considered alongside the riser height. The standard rule of thumb is: 2 × riser height + tread depth = 600 to 650 mm (approximately 24 to 26 inches). A typical residential stair tread measures between 220 and 300 mm (roughly 9 to 12 inches) in depth.
Building codes in most countries specify minimum tread dimensions. In the UK, Building Regulations Approved Document K requires a minimum going (tread depth) of 220 mm for private stairs. In the US, the International Residential Code specifies a minimum tread depth of 254 mm (10 inches). These requirements ensure stairs provide adequate foot support.
Common materials for stair treads include solid hardwood, softwood, concrete, natural stone, and steel. Hardwood treads such as oak or beech are popular in residential settings for their durability and appearance. For exterior stairs, materials with high slip resistance and weather durability are essential, such as textured concrete or stone with anti-slip strips.
The nosing, which is the front edge of the tread that projects slightly beyond the riser, improves safety by increasing the effective tread area. Most building codes limit the nosing projection to around 25 mm to prevent tripping hazards.
Related terms
- Tread depth
- Riser
- Staircase
- Stringer
- Nosing
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