CSLB C-39 Roofing ContractorSteep-Slope RoofingMedium
A roofer is installing a new composition shingle roof on a residential property. The roof has a slope of 6:12. What is the maximum acceptable exposure for a standard 36-inch long, 3-tab asphalt shingle on this roof?
- A5 inches
- B4 inches
- C5 5/8 inches
- D6 inches
Show answer & explanationAnswer & explanation
Correct answer: C. 5 5/8 inches
Standard 3-tab asphalt shingles are typically 12 inches wide by 36 inches long. With a 5 5/8 inch exposure, this allows for a 2-inch headlap (12 inches - 5 5/8 inches exposure - 3 3/8 inches cutout/overlap = 3 inches hidden portion; 3 inches hidden portion - 1 inch top lap = 2 inches headlap). This exposure is standard for slopes of 4:12 and greater.
Why the other options are wrong
- A. 5 inches of exposure is also less than the standard, leading to more overlap than necessary.
- B. 4 inches of exposure would result in an excessive headlap, reducing material efficiency.
- D. 6 inches of exposure would result in an insufficient headlap, compromising water shedding on a 6:12 slope.
Asphalt Shingle Exposure
Exposure is the portion of a shingle that is left exposed to the weather.
- Determines headlap.
- Varies by shingle type and slope.
- Critical for proper water shedding.
Memory trick: Five and five-eighths, for the standard shingle's fate.