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Calculate winding stair dimensions including riser height, tread depths, landing sizes, and code compliance. Essential for L-shaped and U-shaped staircase design and planning.
Typical values: 2-5 steps
Standard: 12" from narrow end
Enter values to calculate winder stair dimensions
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Winder stairs are staircases that change direction using wedge-shaped treads instead of a landing. These winding treads are narrower on one side and wider on the other, allowing stairs to turn 90° (L-shaped) or 180° (U-shaped).
Winder stairs save space compared to conventional stairs with landings and are commonly used in residential homes, attics, and tight spaces. However, they are more challenging to navigate than traditional stairs.
Range: 7.00" - 7.75" maximum
Most stairs use 7.5" for consistency
Minimum: 10" measured at walkline
Minimum 4" at narrow end of winder
Minimum: 80" vertical clearance
Measured from tread to obstruction
Residential: 36" minimum clear width
Commercial: 44" minimum
Minimum: 36" × 36" at top and bottom
Must extend full stair width
Height: 34" - 38" from nosing
Continuous handrails required
The walkline is an imaginary line where people naturally walk on the stairs. On winders, it's typically positioned 12 inches from the narrow end. All tread depth requirements are measured at this walkline, not at the edges.
Winder treads have three critical dimensions:
Typical winder staircases use 3 winding steps for a 90° turn (L-shaped). For 180° turns (U-shaped), use 4-5 winders. More winders create gentler transitions but take up more space.
Building codes vary by jurisdiction. Always check your local building codes before construction. This calculator provides guidance based on the International Building Code (IBC), but your location may have different requirements.
All risers in a flight must be within 3/8 inch of each other. This prevents trips and falls. Consistency is crucial for safety.
All winder treads must have the same depth at the walkline. Adjacent treads cannot differ by more than 1/4 inch.
Handrails must be continuous through winders. They cannot drop below the height requirement at winding sections, which makes design more complex.
Wider stairs accommodate furniture moving and feel less cramped at winder sections.
Place straight stairs first, then winders. Gives users time to adjust before the turn.
Equal-width winders throughout the turn provide better visual balance and safety.
Winders create shadows. Add lighting fixtures to illuminate the turn points well.
Use double handrails in winders for better safety and grip through the transition.
Apply tactile nosing to all winder tread edges for safety and visibility.
Winder stairs can be safe when properly designed and built to code. However, they are generally more challenging to navigate than straight stairs with landings, especially for people with mobility issues. Handrails are critical for safety.
Winder stairs can save 20-30% of floor space compared to straight stairs with landings. The exact savings depends on stair dimensions and configuration.
Yes, but they're subject to stricter code requirements in commercial settings. Accessible routes and public stairs typically require landings instead of winders. Consult local building codes.
L-shaped winders (90° turn) use 3 typical steps, while U-shaped winders (180° turn) use 4-5 steps. U-shaped takes more space but provides a smooth transition in opposite directions.
Divide total rise by the total number of risers needed. For example: 96" rise ÷ 13 risers = 7.38" per riser. Keep riser height between 7.0" and 7.75" per IBC code.
While winder stairs don't have landings at the turn, they still require landing areas at the top and bottom of the staircase (minimum 36" × 36" for residential).
The standard walkline position is 12 inches from the narrow end of winder treads. This represents the natural walking path and is where minimum tread depths are measured.
Yes, carpet can be installed on winder stairs, but it's more complex due to angled treads. Use quality padding and professional installation to avoid wrinkles and safety issues.
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