Concrete Curb and Gutter Calculator
Estimation Results
How to Calculate Curb and Gutter Concrete
Calculating the volume of concrete for a curb and gutter project involves breaking the shape down into two distinct rectangular sections: the horizontal gutter (the flat pan that channels water) and the vertical curb (the upright portion).
To find the total volume, we use the following formula:
- Step 1: Calculate Gutter Area (sq ft) = (Gutter Width in inches / 12) × (Gutter Thickness in inches / 12)
- Step 2: Calculate Curb Area (sq ft) = (Curb Width in inches / 12) × (Curb Height in inches / 12)
- Step 3: Total Area = Gutter Area + Curb Area
- Step 4: Total Volume (cubic ft) = Total Area × Total Length (ft)
- Step 5: Convert to Yards = Total Volume / 27
Typical Curb and Gutter Dimensions
While specifications vary by local municipality, common residential dimensions include an 18-inch to 24-inch gutter width with a 6-inch thickness, and a 6-inch wide curb extending 6 inches above the gutter pan. Industrial or heavy-traffic areas may require thicker pans and higher curbs for better drainage capacity.
Important Considerations
The Waste Factor: Always include a waste factor of at least 5% to 10%. Concrete can be lost during the pour, absorbed by dry subgrade, or variations in the trench depth can lead to higher consumption than a theoretical calculation suggests.
Subgrade Preparation: Ensure your base is compacted. Soft spots in the soil will lead to concrete settling, which can crack the curb and cause water to pool instead of flow.
Example Calculation
If you are pouring 50 feet of curb with a 12″ gutter (6″ deep) and a 6″ wide curb (6″ high above the gutter):
- Gutter: (12/12) * (6/12) = 0.5 sq ft
- Curb: (6/12) * (6/12) = 0.25 sq ft
- Total Area: 0.75 sq ft
- Volume: 0.75 * 50 = 37.5 cubic feet
- Cubic Yards: 37.5 / 27 = 1.39 yards (before waste)