CSLB C-39 Roofing ContractorSteep-Slope RoofingMedium
A roofing contractor is installing new wood shakes on a roof with a 6:12 slope. The shakes are 18 inches long. According to standard practice for single coverage, what should be the maximum weather exposure for these wood shakes?
- A7.5 inches
- B5.5 inches
- C8.5 inches
- D6.0 inches
Show answer & explanationAnswer & explanation
Correct answer: A. 7.5 inches
For 18-inch wood shakes on a 6:12 slope with single coverage, the maximum weather exposure is 7.5 inches. This calculation is derived from dividing the shake length by a factor of 2.4.
Why the other options are wrong
- B. 5.5 inches is too little exposure for 18-inch shakes on this slope.
- C. 8.5 inches would be excessive exposure, compromising weather integrity for 18-inch shakes.
- D. 6.0 inches is incorrect; exposure should be based on the shake length and slope.
Wood Shake Exposure (Single Coverage)
The exposed portion of a wood shake to the weather, measured from the butt of the shake to the butt of the shake in the course above it. Exposure varies by shake length and roof slope.
- Crucial for water shedding.
- Single coverage means one layer of shakes covers the underlayment.
- Typically, exposure is derived from shake length divided by a factor.
Memory trick: Exposure is key, for a dry roof, you see.