CSLB C-39 Roofing ContractorSteep-Slope RoofingMedium
A roofing inspector is examining a newly installed slate roof. The slates are 18 inches long, and the roof has a 5:12 slope. To calculate the exposure, the side lap of the slate needs to be confirmed. What is the typical minimum side lap required for standard slate roofing tiles?
- A4 inches
- B1 inch
- C2 inches
- D3 inches
Show answer & explanationAnswer & explanation
Correct answer: D. 3 inches
For standard slate roofing, a minimum side lap of 3 inches is typically required. This ensures that the vertical joints between slates in adjacent courses are adequately covered, preventing water intrusion.
Why the other options are wrong
- A. 4 inches is excessive and not a standard minimum requirement for slate side lap.
- B. 1 inch of side lap is insufficient for slate and would compromise water tightness.
- C. 2 inches of side lap is generally insufficient for standard slate applications.
Slate Roof Side Lap
Side lap is the horizontal overlap of a slate over the vertical joint of the two slates in the course directly below it.
- Prevents water intrusion at vertical joints.
- Crucial for weather resistance.
- Typically 3 inches for standard slate.
Memory trick: Three inches wide, to keep the joints inside.