Special Stairways: Spiral Staircase Guidelines

While most staircases follow a standard design, there are some special types that have unique considerations. This section focuses on spiral staircases, which are often used in situations where space is limited.

Spiral Stairways: Compact and Elegant

Spiral staircases, with their winding design around a central pole, offer a space-saving solution while adding a touch of elegance to your home. However, their unique construction requires specific attention to building codes to ensure safety and comfort.

Key Requirements for Spiral Stairways:

  • Minimum Width: The clear width of a spiral staircase, measured at and below the handrails, should be at least 26 inches. This ensures enough space for comfortable movement.
  • Walkline Radius: The walkline, which represents the typical path someone takes when using the stairs, should have a maximum radius of 24 ½ inches. This helps maintain a comfortable walking pattern on the curved steps.
  • Tread Depth: Each tread (the horizontal part of the step) should have a minimum depth of 6 ½ inches at the walkline. This provides adequate space for your foot to land securely.
  • Uniform Treads: All treads on a spiral staircase must be identical in size and shape. This ensures a consistent and predictable walking experience.
  • Maximum Riser Height: The risers (the vertical parts of the steps) should be no more than 9 ½ inches high. This helps prevent the staircase from becoming too steep and difficult to climb.
  • Headroom: The minimum headroom for a spiral staircase is 6 feet 6 inches. This ensures enough clearance to avoid bumping your head as you ascend or descend.

Bulkhead Enclosures: Basement Access

Bulkhead enclosures are structures that provide access to basements from the outside. They typically have a stairway leading down to the basement level.

Code Exemptions:

  • Limited Height: If the height from the basement floor to the ground level outside is no more than 8 feet, and the opening to the stairway is covered by a bulkhead enclosure with hinged doors or another approved method, the stairway may be exempt from certain building code requirements. This exemption recognizes that these stairways are typically short and used infrequently.

By understanding these specific requirements for spiral staircases and bulkhead enclosures, you can ensure your unique stairway design is both beautiful and safe, complying with all applicable building codes.