Is a Landing Required at an Exterior Door Under IRC 2018 R311.3?

Quick Answer

Yes — under IRC 2018 Section R311.3, a landing is required on both the inside and outside of every exterior door. The landing must be at least as wide as the door and at least 36 inches in the direction of travel. The floor or landing inside an exterior door may not be more than 1.5 inches below the threshold. A door at the top of a stairway requires a landing before the stair begins.

What R311.3 Actually Requires

IRC 2018 Section R311.3 specifies landings at doors as follows:

Inside landings: There shall be a floor or landing on each side of every exterior door. The floor or landing on the interior side of the door shall not be more than 1.5 inches lower than the door threshold. This prevents stepping down into the interior immediately upon opening the door.

Outside landings: The floor or landing on the exterior side shall not be more than 7-3/4 inches below the door threshold. This allows a step down from the threshold to the exterior landing but limits the drop to one typical riser height.

Landing dimensions: Landings shall have a width not less than the door served, and a length in the direction of travel not less than 36 inches.

Exception for door at top of stair: The exterior landing may be lower than the threshold by the riser height of one step — up to 7-3/4 inches — when the door at the top of a stair swings away from the stair. A door that swings toward the stair (toward the person descending) requires a landing before the stair begins.

Section R311.3 also requires that landings shall not slope more than 2 percent (1/4 inch per foot) in any direction for drainage. This prevents standing water at door thresholds while maintaining a level walking surface. Raised thresholds and saddle strips are common installations to manage the 1.5-inch interior tolerance while providing weather protection.

The 36-inch depth requirement applies in the direction of travel, meaning a person must be able to stand fully within the landing zone — inside or outside the door — before encountering a grade change, step, or stair. The door's swing arc must be considered: a door that opens outward must be able to swing fully open without the occupant needing to step back off the landing. Coordinate door swing direction with landing dimensions during design.

Why This Rule Exists

A door without a landing on the interior side presents a tripping hazard — a person opening the door and stepping forward immediately steps down into a floor that is lower than the threshold. On the exterior side, a landing provides a safe standing surface when operating the door, particularly when hands are full (groceries, tools) and when the weather is wet or icy. A door at the top of a stairway without a landing forces the occupant to open the door while standing on a stair tread, creating a fall risk when the door swings toward them. The 36-inch minimum depth gives a person adequate standing room to fully open the door and step clear before beginning descent.

What the Inspector Checks at Rough and Final

At framing inspection the inspector verifies that the exterior door framing allows for the exterior landing at the required elevation relative to the threshold. At final inspection the inspector checks: (1) interior landing — the floor must not drop more than 1.5 inches below the threshold; (2) exterior landing — must be within 7-3/4 inches below the threshold; (3) landing width at least equal to the door width; (4) landing depth at least 36 inches in the direction of travel; (5) landing slope not more than 2 percent. The inspector will also check that landings are solid, stable, and of durable material (concrete, masonry, pressure-treated wood on joists, etc.).

What Contractors Need to Know

The most critical coordination point is the relationship between the exterior landing elevation and the first-floor finish floor elevation. The exterior landing must be within 7-3/4 inches below the threshold. If the exterior concrete slab is poured at a level that drops the landing more than 7-3/4 inches below the threshold, the landing fails R311.3. Coordinate finish floor height and exterior grade with the threshold elevation during framing and before the concrete slab is poured.

Also coordinate the interior side: the finished floor — whether hardwood, tile, or other material — must not drop more than 1.5 inches below the threshold. A raised threshold combined with a raised tile floor may bring both sides into compliance; a thick tile floor installed after framing was complete may bring the interior side above the threshold and create a different tripping hazard. Plan finish floor thicknesses before setting framing heights.

Sloped exterior concrete landings are a frequent failure point. Contractors sometimes slope the landing aggressively away from the house to ensure drainage, exceeding the 2 percent maximum. Use a level and slope gauge when finishing concrete landings — the 2 percent maximum slope is approximately 1/4 inch per foot. Mark the required slope on the forms before the pour to ensure the finisher stays within the code limit.

What Homeowners Get Wrong

Homeowners planning accessible or aging-in-place modifications sometimes assume that adding a ramp outside an exterior door satisfies R311.3. A ramp that begins within the 36-inch landing zone — so that the door swings over the ramp surface — can violate R311.3 if the ramp surface drops more than 7-3/4 inches below the threshold within the landing zone. Ramps must be carefully designed so that the flat landing at the door threshold is maintained before the ramp slope begins.

The most common homeowner error is a sunken interior entry. Many older homes and renovation projects feature an entry step that drops from the door threshold level into the main floor, creating a 3-inch or greater drop inside the door. While this may have been acceptable under older codes, IRC 2018 R311.3 limits the interior drop to 1.5 inches. Homeowners remodeling entry areas should verify the threshold-to-floor dimension before selecting finish floor materials.

Another frequent error is pouring an exterior concrete patio slab at a level that drops more than 7-3/4 inches below the door threshold. This happens when homeowners want the patio close to grade for a level yard transition. If the patio surface drops more than 7-3/4 inches from the door, a step or raised landing area must be added between the door and the patio.

Homeowners also sometimes forget the 36-inch landing depth requirement for doors at the top of stairs. A door with only 12 inches of landing before the stair begins violates R311.3 — the landing must extend 36 inches from the door in the direction of travel.

Another overlooked point is that exterior landings must be maintained in a safe condition throughout the life of the structure. A concrete landing that was code-compliant at final inspection but has since heaved due to frost, settled unevenly, or developed a surface crack that creates a trip hazard at the threshold is a safety defect even if it was originally installed correctly. Homeowners should inspect exterior landings periodically — particularly after freeze-thaw seasons — and repair settlement, cracking, or heaving that changes the landing slope or elevation relative to the threshold. A landing that has settled to more than 7-3/4 inches below the threshold is no longer compliant and requires remediation.

State and Local Amendments

IRC 2018 R311.3 is adopted in Texas, Georgia, Virginia, North Carolina, South Carolina, Tennessee, Alabama, Mississippi, Kentucky, and Missouri without significant amendment. The landing requirements are practical safety provisions that most jurisdictions apply as written. Some local codes specify additional materials standards for exterior landings (concrete or masonry rather than wood) in climates with freeze-thaw cycles, but the dimensional requirements are typically as IRC states.

IRC 2021 did not change the landing dimensions or the 1.5-inch interior threshold tolerance. The 7-3/4-inch exterior maximum drop and the 36-inch depth requirement are unchanged in the 2021 edition. The slope limitation of 2 percent is also unchanged. States on both IRC 2018 and IRC 2021 apply the same landing requirements.

When to Hire a Licensed Contractor

Adjusting an existing exterior door landing — raising a sunken entry, adding concrete steps, or modifying the patio grade at a door — requires a building permit in most jurisdictions when the work involves structural changes or new concrete. A licensed general contractor or masonry contractor can design and install a compliant landing to the correct dimensions and elevation. For interior step-down entry remediation, a licensed contractor familiar with finish floor systems and threshold details can provide a compliant solution without major structural modification.

Common Violations Found at Inspection

• Interior floor more than 1.5 inches below door threshold — common at entry doors where the interior floor drops to a lower level
• Exterior landing more than 7-3/4 inches below the door threshold — slab or concrete patio poured too low
• Landing width less than the door width — step at a narrow exterior door that is narrower than the door unit
• Landing depth less than 36 inches — particularly at back doors opening to small landings before stairs begin
• Landing slope exceeding 2 percent — exterior concrete slab sloped away for drainage but at more than the allowable 2 percent maximum
• No landing provided at all — door opens directly to stair tread without any flat landing area
• Wooden landing that has deteriorated and is not structurally sound — inspector may flag as unsafe regardless of dimensional compliance