What are the National Building Code of Canada (NBC Part 9) requirements for private stairs?

Under NBC 2020 Part 9 (Section 9.8) for private stairs within a dwelling unit: riser height (rise) must be between 125 mm and 200 mm; rectangular tread depth (run) must be between 255 mm and 355 mm; minimum clear stair width is 860 mm; minimum vertical headroom is 1,950 mm (1.95 m); and step uniformity requires adjacent risers/treads within ±5 mm and overall flight variance within ±10 mm.

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Free NBC Stair Calculator Canada — Rise, Run & Stringer (Part 9)

Calculate exact riser count, riser height, tread run, total run, and diagonal stringer cut length in both mm and ft / inches — with automatic verification against National Building Code of Canada (NBC 2020 Part 9) private stair requirements.

1. Floor-to-Floor Rise & Tread Dimensions

Total Floor-to-Floor Rise (mm) · [8' 11.9"]

Preferred Riser Height (mm) · [NBC: 125–200 mm]

Number of Risers (Auto = 15)

Tread Run Depth (mm) · [NBC: 255–355 mm]

Clear Width (mm) · [≥860]

Headroom (mm) · [≥1950]

Top Landing Mount

NBC 2020 Part 9 (Private Stairs) Reference Limits:

• Rise (Riser Height): 125 mm to 200 mm (4.92" – 7.87")

• Run (Rectangular Tread): 255 mm to 355 mm (10.04" – 13.98")

• Minimum Clear Width: 860 mm (33.86") · Headroom: ≥ 1,950 mm (1.95 m)

• Uniformity: Adjacent steps ±5 mm max · Overall flight ±10 mm max

NBC PART 9 STAIR & STRINGER CUT SHEET

Chinook Framing & Millwork Ltd.

Altadore Infill — Main to Upper Staircase

NBC PART 9 COMPLIANT

Slope Angle: 33.1°

Number of Risers15 Risers(14 Treads)

Exact Riser Height182.7 mm(7.19")

Individual Tread Run280 mm(11.02")

Total Floor-to-Floor Rise2740 mm (8' 11.9")

Total Horizontal Run3920 mm (12' 10.3")

Diagonal Stringer Length4680 mm (15' 4.3")

NBC 2020 Part 9 (Section 9.8 Private Stairs) Verification

Dimension	NBC Part 9 Rule	Your Design	Status
Riser Height (Rise)	125 – 200 mm	182.7 mm (7.19")	PASS
Tread Depth (Run)	255 – 355 mm	280 mm (11.02")	PASS
Clear Stair Width	Min 860 mm	915 mm (36.02")	PASS
Vertical Headroom	Min 1,950 mm (1.95 m)	2050 mm (2.05 m)	PASS

Step Uniformity Tolerance (NBC 9.8.4.4): Adjacent risers or treads must not vary by more than ±5 mm (3/16"), and the difference between the largest and smallest riser or tread in a flight must not exceed 10 mm (3/8"). Account for finished flooring thickness at top and bottom landings!

Generated by Alberta Studio — Free Tools · albertastudio.devVerify against current provincial building code adoption

Export Framing & Stringer Cut Sheet (PDF)

Print for the jobsite saw bench or attach to framing drawings.

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Code Disclaimer: For informational purposes only. Always verify stair rise, run, nosing projection, handrail height, and public vs. private classification against the currently adopted provincial building code (e.g., National Building Code — Alberta Edition, BCBC, or Ontario Building Code) and local authority having jurisdiction.