Residential Ramp Code — Slope, Landings & Handrails
The IRC’s ramp rules are short: one slope limit, one exception, landings where you start, stop, turn, or pass a door, and a handrail once the ramp climbs more than 6 inches.
Worth knowing
- At 1:12, every inch of rise costs a foot of run plus landings — a 24 in. porch height is a 24 ft ramp before landings. Measure before promising a straight shot.
- ADA standards (1:12, 30 in. max rise per run, two handrails) govern public accommodations, not private homes — but they are a sound spec when building for a wheelchair user.
- Cross slope matters too: keep it at or under 1:48 or wheels track sideways in rain and ice.
- Wood ramp surfaces get slick — composite boards or grit strips are cheap insurance, and some jurisdictions require a slip-resistant surface.
Common questions
What does the code say about maximum slope for Ramps?
1 unit vertical in 12 units horizontal (8.3%). (IRC R311.8.1)
What does the code say about steeper exception for Ramps?
Up to 1:8 permitted only where a 1:12 ramp is technically infeasible due to site constraints. (IRC R311.8.1)
What does the code say about landings for Ramps?
Minimum 36 in. × 36 in. landings at the top, at the bottom, where doors open onto the ramp, and where the ramp changes direction. (IRC R311.8.2)
Adopted edition by state
Base-code year from BuildSpec’s adoption records. States often amend the base code, and your city or county may differ, so confirm with your building department.
Related sections and guides
This guide is BuildSpec’s own summary, not code text. It cites the 2021 International Residential Code and the 2023 National Electrical Code as model standards. The IRC 2021 text itself is in the Code Library for signed-in members; BuildSpec publishes no NEC text, which is at nfpa.org.Neither is an adoption record: your state may be on a different edition with amendments — check your jurisdiction page or get an Address Report.