Michigan Stair Code: Your Ultimate Guide to Passing Inspection

Navigating the complexities of the Michigan Stair Code can feel daunting, but understanding the key regulations is crucial for construction projects. Local building departments enforce these rules, ensuring safety and compliance with state standards. The International Residential Code (IRC) serves as a foundational document, often referenced alongside Michigan-specific amendments. Architects and contractors rely on these guidelines to build safe and accessible stairways, ensuring they meet all requirements under the Michigan Stair Code. Failing to comply with these specifications can lead to costly delays and revisions, so a firm understanding of the Michigan Stair Code is essential for a successful project.

Image taken from the YouTube channel Perkins Builder Brothers , from the video titled Geeking Out on Building Codes | Handrails .

Michigan Stair Code: Your Ultimate Guide to Passing Inspection

Navigating the complexities of the Michigan stair code can be daunting for homeowners, contractors, and developers alike. This guide provides a comprehensive overview of the key requirements, ensuring your stairways are safe, compliant, and ready to pass inspection. Understanding and adhering to these regulations is crucial for the safety of occupants and avoiding costly rework.

General Requirements and Definitions

Before diving into specific measurements, it's important to understand some basic terms and overarching principles governing stair construction in Michigan. The Michigan Building Code references the International Building Code (IBC) and the International Residential Code (IRC) for specifics, depending on the type of structure (commercial vs. residential).

• Rise: The vertical distance from the top of one tread to the top of the next.
• Run (Tread Depth): The horizontal distance from the front edge of one tread to the front edge of the next.
• Nosing: The protruding edge of a tread that extends beyond the riser below.
• Handrail: A rail for grasping by hand to provide stability and support.
• Guardrail (Guard): A protective barrier around an elevated area to prevent falls.

Stair Dimensions: Rise and Run

One of the most critical aspects of stair code compliance involves the dimensions of the risers and treads. Precise measurements are essential for safe and comfortable stair use.

• Residential (IRC):
  • Maximum Riser Height: 8 1/4 inches (210 mm).
  • Minimum Tread Depth: 9 inches (229 mm).

• Commercial (IBC):

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  • Maximum Riser Height: 7 inches (178 mm).
  • Minimum Tread Depth: 11 inches (279 mm).

  Important Note: These are general guidelines. Local jurisdictions may have stricter requirements. Always check with your local building department.

Consistency is Key

Variations in riser height or tread depth can create tripping hazards. The code emphasizes consistency throughout the entire stairway.

• Maximum Variation in Riser Height: 3/8 inch (9.5 mm) between the tallest and shortest riser in any flight of stairs.
• Maximum Variation in Tread Depth: 3/8 inch (9.5 mm) between the deepest and shallowest tread in any flight of stairs.

Handrail Requirements

Handrails provide crucial support and are mandatory for most stairways. Compliance involves height, grip size, and continuity.

• Handrail Height:

  • Must be between 34 inches (864 mm) and 38 inches (965 mm) above the stair nosing. Measure vertically from the leading edge of the tread to the top of the gripping surface of the handrail.

• Grip Size:

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  • Non-circular Handrails: Perimeter dimension of 4 inches (102 mm) to 6 1/4 inches (160 mm) with a maximum cross-sectional dimension of 2 1/4 inches (57 mm).
  • Circular Handrails: Diameter of 1 1/4 inches (32 mm) to 2 inches (51 mm).

• Continuity:

  • Handrails must be continuous for the full length of the stair flight. Exceptions exist for short interruptions caused by newel posts.
  • The inside handrail of switchback or dogleg stairs shall be continuous between flights.

• Clearance:

  • There must be a minimum clearance of 1 1/2 inches (38 mm) between the handrail and the wall.

Guardrail (Guard) Requirements

Guardrails (often simply called "guards") are essential safety features designed to prevent falls from elevated surfaces.

• Height:

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  • Guards are required on any open-sided walking surface that is 30 inches (762 mm) or more above the floor or grade below.
  • Residential: Minimum height of 36 inches (914 mm).
  • Commercial: Minimum height of 42 inches (1067 mm).

• Opening Limitations:

  • Guards must be constructed to prevent passage of a 4-inch (102 mm) diameter sphere. This is especially important for spacing between balusters.
  • For triangular openings formed by the riser, tread, and guardrail, the opening must not allow passage of a 6-inch (152 mm) sphere.

Stairway Headroom

Adequate headroom is crucial to prevent head injuries when using the stairs.

• Minimum Headroom: A minimum of 6 feet 8 inches (2032 mm) measured vertically from the sloped plane adjoining the tread nosing to the ceiling or any projection above.

Winder Stairs

Winder stairs, which are stairs with treads that are wider at one side than the other, are permitted under certain conditions, but require careful attention to code requirements.

• Minimum Tread Depth at Narrowest Point: The tread must have a minimum depth of 6 inches (152 mm) at the narrowest point.
• Minimum Tread Depth at the Walkline: The tread depth at the walkline (typically 12 inches from the narrow side) must be no less than the required minimum tread depth for straight stairs (9 inches for residential, 11 inches for commercial).

Landings

Landings provide rest areas within a stairway and must meet certain dimensional requirements.

• Minimum Landing Depth: The landing depth in the direction of travel must be no less than the width of the stairway, but need not exceed 48 inches when the stair has a straight run.

Illumination

Adequate lighting is crucial for safe stair use, especially in low-light conditions.

• Illumination Requirement: Stairways must be illuminated with a light source capable of providing a minimum of 1 footcandle (10.76 lux) of illumination on the treads and landings. The lighting switch should be located at both the top and bottom of the stairway, or a motion-activated system should be in place.

Additional Considerations

While the above covers the core requirements, several other factors can influence code compliance.

• Stairway Width: Minimum width requirements vary depending on the occupancy and use of the building. Consult the specific code for your project.
• Special Needs: Consider accessibility requirements for individuals with disabilities. This may necessitate ramps or other modifications to the stairway design.
• Local Amendments: Remember that local jurisdictions may amend the state building code. Always verify requirements with your local building department before starting construction.

Video: Michigan Stair Code: Your Ultimate Guide to Passing Inspection

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Hopefully, this breakdown gives you a clearer picture of the Michigan Stair Code! It's definitely something to keep in mind when you're planning any kind of stairway project, to make sure you're meeting all the necessary regulations under the Michigan Stair Code.