CSLB C-27 Landscaping ContractorPlanning and EstimatingMedium
A C-27 contractor is reviewing a landscape design plan that specifies a new 400 square foot paver patio. The plan includes a detailed layout for the paver pattern and calls for 6 inches of compacted aggregate base. The contractor estimates that the subgrade will need to be excavated to an average depth of 8 inches to accommodate the base and pavers. What is the estimated volume of soil (in cubic yards) that needs to be excavated?
- A19.8 cubic yards
- B14.8 cubic yards
- C9.9 cubic yards
- D7.4 cubic yards
Show answer & explanationAnswer & explanation
Correct answer: C. 9.9 cubic yards
The excavation depth is given as 8 inches. The area is 400 sq ft. Volume = Area x Depth. Volume = 400 sq ft * (8/12) ft = 400 * 0.6667 = 266.67 cubic feet. To convert to cubic yards, divide by 27 (since 1 cubic yard = 27 cubic feet). 266.67 / 27 = 9.876 cubic yards, which rounds to 9.9 cubic yards.
Why the other options are wrong
- A. This is approximately double the correct volume, possibly from an error in depth or conversion.
- B. This is approximately double the correct volume, possibly from an error in depth or conversion.
- D. This would be the volume if the excavation depth was 6 inches (400 * 0.5 / 27).
Excavation Volume Calculation
Determining the total amount of soil or material to be removed from a site, calculated by multiplying the area by the excavation depth and converting to cubic yards.
- Volume = Area x Depth.
- Depth must be in feet for area in square feet.
- 1 cubic yard = 27 cubic feet.
Memory trick: Area times Depth divided by Twenty-Seven, that's the cubic yard heaven!