Model a Straight, L, or U Stair with the Run Tool

1. Open the Floor Plan of the lower level (e.g. Level 0).
2. On the Architecture tab, click Stair — Revit enters stair assembly mode with Run active by default.
3. Set the vertical constraints in Properties before drawing:
   • Base Level = the level the stair starts on (e.g. Level 0).
   • Top Level = the level it must reach (e.g. Level 1).
   • Desired Number of Risers — Revit calculates this from the level height and the type's riser limit; adjust if needed.
   • Actual Tread Depth (e.g. 280 mm).
4. Check the riser/tread rules in the type:
   1. Click Edit Type and review Maximum Riser Height (e.g. 175 mm) and Minimum Tread Depth.
   2. These limits are why Revit refuses "impossible" stairs — change the type, not the rules, if you need another geometry.
5. Draw the run(s) in plan with the Straight run component:
   • Straight stair: click a start point, drag in one direction, and click when the counter under the cursor reads 0 risers remaining.
   • L-shaped stair: click the start, click again roughly halfway (e.g. after 9 of 18 risers), then continue at 90° — Revit inserts a landing automatically between the two runs.
   • U-shaped stair: same idea with two 180°-opposed runs; use the Location Line and Actual Run Width in the Options Bar to control the gap between flights.
6. Adjust before finishing:
   • Drag the run or landing shape handles to reposition flights.
   • Select a run and check its Relative Top Height if you split risers unevenly.
7. Click the green ✓ (Finish Edit Mode) — Revit builds the stair and places Railings on both sides (set the type beforehand via the Railing button on the ribbon).
8. Verify in a Section or 3D view: the last tread must land exactly on the Top Level, with no riser missing at the top.

Note: Because the stair is constrained to levels, changing a storey height later re-runs the riser calculation automatically — a stair drawn as dumb geometry would silently stop short of the floor.

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Taught in

• New for 2026 — first taught in BIM + Computational Workflow 2026.