Stair landing code requirements under the International Residential Code come down to a few fixed numbers: a landing at the top and bottom of every stairway, each at least 36 inches deep and at least as wide as the stairs, and no single flight rising more than 147 inches (about 12 feet 3 inches) without an intermediate landing. Miss any of those dimensions and the framing usually has to come out before an occupancy permit will issue.
Where a Landing Is Required
IRC Section R311.7.6 requires a floor or landing at both the top and bottom of each stairway. The point is to give you a flat, stable surface before you start climbing or after you finish descending, so that opening a door or turning a corner does not drop you straight onto a slope.
There is one exception worth knowing. A landing is not required at the top of an interior flight, including stairs inside an enclosed garage, as long as no door swings over the stairway. The moment a door at the top swings outward over the steps, the top landing becomes mandatory again, because the door could push a person standing on the stairs backward.
The 147-Inch Rise Limit
IRC Section R311.7.3 caps the vertical rise of any single flight at 147 inches between floor levels or landings. That is 12 feet 3 inches. If your floor-to-floor height is taller than that, you need at least one intermediate landing to break the run into shorter segments.
Standard residential stories fall well under the cap, so this rule usually surfaces in homes with tall ceilings, loft conversions, or deep basement runs. A 15-foot flight without an intermediate platform is both a code violation and a serious hazard: a fall carries far more energy down an uninterrupted run than down one that is split by a landing partway.
Landing Dimensions
Straight Stairs
The landing must be at least as wide as the stairway it serves, measured perpendicular to the direction of travel. For a standard 36-inch-wide residential stairway, that means a 36-inch-wide landing. On a straight-run stair, the landing depth in the direction of travel must also be at least 36 inches, enough room to stand with both feet flat before continuing.
Width has to stay consistent through the system. If your stair is 42 inches wide, the landing is 42 inches wide too. There is no tolerance built into the minimums, so a landing framed an inch short will draw a correction order at the framing inspection.
Winder and Curved Stairs
When a stair turns using winder treads or a curved layout rather than a square or rectangular landing, the dimensional rule changes shape. For landings that are not square or rectangular, the depth at the walkline and the total landing area must each be at least equal to a quarter circle with a radius matching the required landing width. If the stair is 36 inches wide, the landing area must equal a quarter circle with a 36-inch radius. The geometry is worth sketching before framing a turn, because failing the area calculation means pulling treads and reworking the corner.
Headroom Over the Landing
Every point along a stairway, landings included, needs at least 6 feet 8 inches of vertical clearance. Over a landing, that measurement runs straight up from the platform surface. Over the treads themselves, it is measured vertically from the sloped line connecting the tread nosings. This clearance overrides any general ceiling-height rule that might otherwise apply to the space.
Headroom pinches most often in basement stairs tucked under upper-floor joists and in attic conversions where the roofline slopes into the stair path. Checking clearance before you commit to a stair location is far cheaper than relocating ductwork, raising a header, or moving the whole stairway after a failed framing inspection.
Landings at Exterior Doors
A floor or landing is required on both sides of every exterior door. The interior landing has to sit at the same elevation as the door threshold. On the exterior side, the landing can sit up to 7¾ inches below the top of the threshold, but only if the door does not swing outward over it. An outward-swinging exterior door forces the outside landing back up near threshold height so the door cannot strike someone standing below.
Storm and screen doors are treated separately under IRC Section R311.3.3. They are permitted to swing over exterior stairs and landings regardless of the elevation difference, so adding a storm door at an entry where the exterior landing already sits a few inches below the threshold does not create a violation.
Exterior landings also need to shed water without turning into ramps. IRC Section R311.7.7 limits the slope of stair walking surfaces, landings included, to no more than 2 percent, which is ¼ inch of drop per 12 inches of run. Pour a landing with more slope than that and it will fail inspection, and it will be slick in rain or ice.
Guards on Open-Sided Landings
Any landing with an open side more than 30 inches above the floor or ground below must have a guard. That 30-inch measurement is taken vertically at any point within 36 inches horizontally of the open edge. Elevated exterior deck landings are the usual trigger, but open interior landings in two-story foyers fall under the same rule.
Minimum guard height on a landing is 36 inches, measured from the landing surface. On the sloped portion of the stair, the guard must be at least 34 inches, measured from the line connecting the tread nosings. Where the top of the guard also serves as the stair handrail, the height must fall between 34 and 38 inches above the nosing line.
Openings in the guard are limited too. Gaps between balusters must be small enough that a 4-inch sphere cannot pass through, up to a height of 34 inches above the walking surface. The triangular opening formed where a tread, riser, and bottom rail meet on an open stair has a slightly more generous limit: a 6-inch sphere must not pass through.
Lighting at Landings
IRC Section R303.7 requires artificial lighting that illuminates every interior stair tread and landing to at least 1 footcandle, measured at the center of each tread and landing. For stairways with six or more risers, a wall switch is required at each floor level so you can turn the light on before stepping onto the stairs from either end. If the stairway has continuous or automatic illumination, such as a motion sensor that activates on approach, the dual-switch requirement does not apply.
Outside, IRC Section R303.8 requires an artificial light source at the top landing of every exterior stairway. Exterior stairs providing access to a basement from ground level also need a light at the bottom landing. Unless the lighting is continuous or automatic, it must be controlled by a wall switch inside the dwelling.
Handrails Across a Landing
IRC Section R311.7.8.2 requires handrails to run continuously for the full length of each flight, from a point directly above the top riser down to a point directly above the lowest riser. Ends must return to the wall or terminate at a newel post or safety terminal, because open ends snag clothing and bags.
Here is the point homeowners most often get wrong: the handrail has to be continuous within each flight, not across a landing. Where a stair turns at a landing, the rail for the upper flight ends and the rail for the lower flight begins, and a newel post at the turn is allowed to interrupt the rail between flights. A single wrapped rail is permitted when the design supports it, but it is not required. Handrails installed next to a wall must keep at least 1½ inches of clearance between the rail and the wall, so your knuckles clear the surface while you grip.