A very specific request!

The 27 Rule: For a comfortable rhythm, the sum of one riser and one tread should approximately equal 27 inches (e.g., 7" riser + 20" tread).

The Ultimate Guide to Double Stringer Staircase Detail DWG

  • Rise and Run: Exact tread depth (min 10" residential, 11" commercial) and riser height (max 7-3/4").
  • Stringer Slope: Calculated using the Pythagorean theorem. The DWG should call out the angle (typically 30°–35°).
  • Material thickness: e.g., "½" thick A36 steel web" or "2x12 Douglas Fir."
  • Notch geometry (for open stringers): Depth of cut, remaining web depth (should never be less than 5" for steel).

Step 4 – Detail connections

  • Top support: Weld end plate to floor beam or embed in concrete.
  • Bottom support: Notch stringer into concrete slab or mount on base plate.
  • Intermediate support: If span > 4 m, add a landing beam.

The "detail" in your DWG is only as good as its connections. You should provide separate enlarged views for:

Drawing Views

Staircase Dimensions: