Concrete Stair Configurations & Bag Requirements (4 ft Wide)
The table below lists common residential entryway stairs poured at standard 4-foot width with 7.5" risers and 11" treads, including a 10% waste contingency:
| Stair Setup | Landing Depth | Total Rise | Volume (cu yds) | 80 lb Bags | Recommended Pour |
|---|---|---|---|---|---|
| 2 Steps (Garden Entry) | None (0") | 15.0" | 0.26 yd³ | 12 bags | Hand mix in wheelbarrow |
| 3 Steps (Standard Stoop) | 36-inch landing | 22.5" | 1.48 yd³ | 67 bags | Rental mixer or ready-mix |
| 4 Steps (Raised Entry) | 36-inch landing | 30.0" | 2.28 yd³ | 103 bags | Ready-mix delivery |
| 5 Steps (Terrace Stoop) | 48-inch landing | 37.5" | 3.75 yd³ | 169 bags | Ready-mix transit truck |
Residential Stair Building Codes (IRC Section R311.7)
Stairways are subject to strict life-safety building codes because uneven step heights cause trips and falls. Before building forms, verify these key dimensions:
Max Riser Height
7 3/4" (197 mm)No individual step riser may exceed 7.75 inches. Furthermore, the variation between the tallest and shortest riser in a run must not exceed 3/8 inch (0.375").
Min Tread Depth
10.0" (254 mm)The horizontal tread run must be at least 10 inches deep. Slope treads slightly (approx 1/8" per foot) away from the house to ensure rainwater drains off rather than pooling.
Top Landing Depth
36.0" MinimumEvery exterior exit doorway requires a landing platform measuring at least 36 inches in the direction of travel, with width equal to or greater than the door width.
Carpentry Tips for Pouring Concrete Steps
1. Bevel the Bottom of Form Boards
When cutting 2×8 lumber for step risers, rip a 45-degree bevel along the bottom edge. This bevel allows your concrete finishing trowel to float all the way to the back of the tread underneath without hitting the wooden form board.
2. Dowel into the Existing House Foundation
Steps that are poured adjacent to an existing foundation wall must be anchored with 1/2" steel rebar dowels drilled 4 inches into the foundation and secured with epoxy adhesive. This prevents the heavy concrete stair mass from settling away from the door sill.
3. Apply a Medium Broom Non-Slip Finish
Never finish outdoor stair treads with a smooth steel trowel—wet concrete becomes as slick as ice. After floating the treads level, lightly pull a horsehair masonry finishing broom across each step perpendicular to foot traffic to create slip-resistant micro-grooves.