CSLB C-39 Roofing ContractorSteep-Slope RoofingMedium
A crew is installing 24-inch wood shakes using a double-coverage application on a roof with a 5:12 slope. What weather exposure should be used?
- A7.5 inches
- B12 inches
- C10 inches
- D16 inches
Show answer & explanationAnswer & explanation
Correct answer: C. 10 inches
For 24-inch wood shakes installed on slopes of 4:12 or steeper, the standard weather exposure per CRSMC/code tables is 10 inches, providing adequate double-coverage protection; 7.5 inches applies only to slopes flatter than 4:12.
Why the other options are wrong
- A. 7.5 inches is the exposure for slopes less than 4:12, not this steeper roof.
- B. 12 inches exceeds the code-recognized maximum exposure for this shake length.
- D. 16 inches would leave the shakes with almost no overlap coverage.
Wood Shake Exposure by Slope
Weather exposure for wood shakes depends on shake length and roof slope to ensure proper double-coverage weatherproofing.
- 24in shakes: 10in exposure on slopes 4:12+, 7.5in below 4:12
- 18in shingles: 5.5in exposure typical
- Steeper slopes allow greater exposure safely
Memory trick: Steep slope, ten-inch scope.