Stairs, Elevated Areas, & Deck Requirements
COMM 21.04 - Stairs and Elevated Areas
Every interior and exterior stairs, including tub access steps but excluding non-required basement stairs which lead directly to the building exterior and stairs leading to attics or crawl spaces, shall conform to the requirements of this section.
1. Stair Details
(a) Width - Stairs shall measure at least 36 inches in width. Handrails and associated trim may project no more than 4 ½" into the required width at each side of the stairs.
(b) Headroom - Stairs shall be provided with a minimum headroom clearance of 76 inches. The clearance shall be measured vertically from a line parallel to the nosing of the treads to the ceiling or soffit directly above that line.
(c) Treads and risers
- Except for spiral stairs and winders, risers may not exceed 8 inches in height measured vertically from tread to tread. Treads shall be at least 9 inches wide measured horizontally from nosing to nosing.
- Within individual stairways, tread widths and riser heights may vary in uniformity by a maximum of 3/8 inches. Variations in uniformity may not cause either dimension in subd. 1 to be exceeded.
(d) Winders - Winder steps may be used provided the length of the tread is at least 36 inches and the width of the tread is at least 7 inches measured at a point 12 inches from the narrow end.
(e) Spiral Stairs - Spiral stairs may be used as exit stairs. The tread shall measure at least 26 inches from the outer edge of the supporting column to the inner edge of the handrail and at least 7 inches in width from nosing ot nosing at a point 12 inches from the narrow end of the tread. The riser height shall be uniform and may not exceed 9 ½ inches.
(f) Open risers shall be constructed to prevent the passage of a 4" diameter sphere.
2. Handrails and Guardrails
Handrails or guardrails shall be provided on all open sides of stairs consisting of more than 3 risers and on all open sides of areas that are elevated more than 24 inches above the floor or exterior grade. Handrails and guardrails shall be constructed to prevent the through passage of a sphere with a diameter of 4 inches or larger. Handrails and guardrails shall be designed and constructed to withstand a 200 pound load applied in any direction. Exterior handrails and guardrails shall be constructed of metal, decay resistant, or pressure treated wood, or shall be protected from the weather.
(a) Handrails - Stairs of more than 3 risers shall be provided with at least one handrail for the full length of the stairs.
- Height - Handrails shall be located at least 30 inches, but no more than 38 inches above the nosing of the treads. Measurements shall be taken from the hard structural surface beneath any finish material to the top of the rail. Variations in uniformity are allowed only when a rail contacts a wall or newel post or where a turnout or volute is provided at the bottom steps.
- Clearance - The clearance between a handrail and the wall surface shall be at least 1 ½ inches.
- Winders - Handrails on winder steps shall be placed on the side where the treads are wider.
- Projection - Handrails and associated trim may project into the required width of stairs and landings a maximum of 4 ½ inches on each side.
- Size and configuration. Handrails
- Handrails with a round or truncated round cross sectional gripping surface shall have a maximum whole diameter of 2 inches.
- Handrails with a rectangle cross sectional gripping surface shall have a maximum perimeter of 6 1/4 inches with a maximum cross sectional dimension of 2 7/8 inches.
- Handrails with other cross sections shall have a maximum cross sectional dimension of the gripping surface of 2 7/8 inches with a maximum linear gripping surface measurement of 6 1/4 inches and a minimum linear gripping surface of 4 inches.
- Continuity - Handrails shall be continuous for the entire length of the stairs except in any one of the following cases:
- A handrail may be discontinuous at an intermediate landing.
- A handrail may have newel posts.
- A handrail may terminate at an intermediate wall provided the lower end of the upper rail is returned to the wall or provided with a flared end, the horizontal offset between the two rails is no more than 12 inches measured from the center of the rails, and both the upper and lower rails can be reached from the same tread without taking a step.
- Application - All openings between floors, and open sides of landings, platforms, balconies or porches that are more than 24 inches above grade or a floor shall be protected with guardrails.
- Height - Guardrails shall be located at least 36 inches above the floor. Measurement shall be taken from the hard structural surface beneath any finished material to the top of the rail.
(a) Intermediate landings. A level intermediate landing shall be provided for any stairs with a height of 12 feet of more. Intermediate landings shall be at least as wide as the stairs and shall measure al least 3 feet in the direction of travel. For curved or semicircular landings, the radius of the landing shall be at least equal to the width of the stairs.
(b) Doors at landings. Except as provided in sudbs. 1. To 4., level landings shall be provided on each side of any door located at the top or base of a stairs, regardless of the direction of swing. In the following exceptions, stairways to attached garages or porches are considered interior stairs:
- A landing is not required between the door and the top of interior stairs if the door does not swing over the stairs.
- A landing is not required between the door and the top of an interior stairs of 1 or 2 risers regardless of the direction of swing.
- A landing is not required between a sliding glass door and the top of an exterior stairway of 3 or fewer risers.
- The exterior landing, platform or sidewalk at an exterior doorway shall be located a maximum of 8 inches below the interior floor elevation. The landing, platform or sidewalk shall have a length at least equal to the width of the door.
Comm 21.045 Ramps
Every exterior or interior ramp which leads to or from a required exit shall comply with the requirements of this section.
1. SLOPE - Ramps shall not have a gradient greater than 1 in 8 or one foot of rise in 8 feet of run. Walkways with gradients less than 1 in 20 or one foot of rise in 20 feet of run are not considered to be ramps.
2. SURFACE AND WIDTH - Ramps shall have a slip resistant surface and shall have a minimum width of 36 inches measured between handrails.
3. HANDRAILS - Handrails shall be provided on all open sides of ramps. Every ramp that overcomes a change in elevation of more than 8 inches shall be provided with at least one handrail.
•Ramps which have a gradient greater than 8.33% or 1:12 or one foot rise in 12 feet of run and which overcome a change in elevation of more than 24 inches shall be provided with handrails on both sides.