Flush flooring transitions; max 1/4" eased, 1/2" beveled
NKBA 4th ed §1.3 Floor TransitionsDescription
Transitions between flooring materials should be flush. When height varies between surfaces or at doorways, the transition should be eased (no higher than 1/4") or beveled (no higher than 1/2"). Where a step exists, the riser must be 4-3/4" minimum and 7-3/4" maximum; multiple steps follow the local stair code.
Why this exists
Small height changes are trip hazards and wheel-chair obstructions. The 1/4" / 1/2" thresholds align with ADA + ANSI A117.1 accessibility standards. The 4-3/4"-to-7-3/4" riser range matches code minimums for stair construction.
Measurements
| Property | Operator | Value | Unit | Note |
|---|---|---|---|---|
easedTransitionMax | max | 0.25 | in | Eased transition maximum height |
beveledTransitionMax | max | 0.5 | in | Beveled transition maximum height |
singleStepMin | min | 4.75 | in | Single-step riser minimum |
singleStepMax | max | 7.75 | in | Single-step riser maximum |
Categories
Source
Solver enforcement
Browsable only — the solver does not currently enforce this directive (no spec-level data to check against). This entry exists so the architect personas can cite it in conversation and the user can read what the rule says.
Plan symbols this applies to
These plan symbols invoke this directive when placed on a floor plan. Click any to see where it's drawn and what other rules apply to it.
Related directives
- Bathroom entry doorway · NKBA Bath 1
- Kitchen walkway and work-aisle widths · NKBA Kitchen 6
- Single-door clear opening: 34" minimum (36" door leaf) · NKBA 4th ed §1.1 Doorways
- Wheelchair-maneuvering clearance at doorways · NKBA 4th ed §1.1 Doorways
- Clear floor space at every activity center: 30-32" × 48-52" · NKBA 4th ed §1.5 Clear Floor Space at Activity Centers
Last reviewed 2026-05-14.