Stairs & Handrails

View the Stair and Handrail Handout (PDF).

Residential Stair Requirements

  • Stairs minimum clear width 36 inches above handrail and 31 ½ inches at and below handrail. With handrail on both sides, the minimum width at and below the handrails is 27 inches.
  • Stairs minimum headroom: in new buildings, 6 feet 8 inches. Alterations to existing basement stairways, 6 feet 4 inches, R305.2.2. Exception: 4 ¾-inch floor opening is allowed into clear width.
  • Stairs with four or more risers require a continuous full-length graspable handrail on one side with no open ends or sharp edges located 34 to 38 inches above tread nosing.
  • Open sides of stairs more than 30 inches high require guards at least 34 inches high with less than 4 3/8-inch openings. Guards are measured vertically from tread nosing to top of guard.
  • Treads shall support a 40-pound live load or a 300-pound point load over 4 square inches.
  • Guards and handrails on stairs must support a 200-pound load at any point along the top.
  • Maximum riser height is 7 ¾ inches. Minimum tread depth is 10 inches.
  • A nosing ¾ inch to 1 ¼ inch is required on stairs with solid risers. Exception: A nosing is not required with a minimum 11-inch tread depth.
  • Riser heights, tread depths and nosing projections shall not differ more than 3/8 inch.
  • Riser openings are restricted to less than 4 inches on stairs more than 30 inches high.
  • Triangular openings formed by riser, tread and bottom guard rail must be less than 6 inches.
  • A landing is required at the top and bottom of all stairs. It shall be as wide as the stairs and extend at least 36 inches in the direction of travel.
  • Exception: A landing is not required at the top of interior stairs or in an enclosed garage if a door does not swing over the stairs.
  • The walking surface of treads and landings shall not exceed a slope of ¼ inch per foot.
  • All stairs require an artificial light source. Light for exterior stairs shall be controlled from inside the dwelling or continuously illuminated or automatically controlled.