? the riser height plus one tread depth should be in the 580 mm to 620 mm range. A tread depth of at least 275 mm. Stair width of 900?1100 mm. Treads that are all at the same width. Treads that project past the riser by at least 15 mm, but not more than 25 mm to prevent toes being caught while walking up stairs. A maximum of 17 risers between landings, but 14 is recommended. A handrail on at least one side ? handrails on both sides are safer. No winders ? it is safer to install a landing, it also provides a rest for less mobile users. Handrails which project past the end of the stair. The same surface finish, texture and pattern throughout. A defined, non-slip, front edge to each tread. No reflective or slippery surfaces. Even lighting to make them well illuminated day and night. Light switches at the top and the bottom of the stair. Colour differentiation between the stairs and the surrounding surfaces. No obstructions or distractions. Stair gates in homes with young children. Open risers must not allow a 100 mm diameter sphere (for stairs frequently used by children under 4), or a 130 mm diameter sphere (4 to 6 year-old children), to pass between the treads. This is to prevent children from falling through or becoming stuck between the treads. Stairs are also safer where: Large floor-level windows are not placed on the downward side of a landing. Doors opening off landings