CSLB C-39 Roofing ContractorLow-Slope RoofingHard
A crew is installing a 4-ply BUR system on a 1,200 square foot roof section, requiring 3 interply asphalt moppings at a rate of 23 pounds per square (100 sq ft). How many total pounds of asphalt are needed for the interply moppings?
- A1,104 pounds
- B552 pounds
- C276 pounds
- D828 pounds
Show answer & explanationAnswer & explanation
Correct answer: D. 828 pounds
1,200 sq ft = 12 squares. Asphalt per mopping = 23 lb/square × 12 squares = 276 lb. Total for 3 moppings = 276 × 3 = 828 pounds.
Why the other options are wrong
- A. Overstates the requirement; does not match the correct multiplication.
- B. This equals two moppings' worth, missing the third.
- C. This is the amount for only one mopping, not all three.
BUR Asphalt Mopping Rate Calculation
Built-up roofing requires interply asphalt moppings, typically applied around 20-25 lb per square, and total asphalt needed scales with area and number of moppings.
- 1 square = 100 sq ft
- Total lbs = rate × squares × number of moppings
- Standard interply rate: ~20-25 lb/square
Memory trick: Rate times squares times moppings equals total pounds.