CSLB C-39 Roofing ContractorSteep-Slope RoofingMedium
A roofer is installing clay mission tiles on a residential roof. To ensure proper drainage and prevent water intrusion, what is the generally accepted minimum side lap for these tiles?
- A2 inches
- B3 inches
- C1 inch
- D4 inches
Show answer & explanationAnswer & explanation
Correct answer: B. 3 inches
For most clay and concrete tiles, including mission tiles, a minimum side lap of 3 inches is generally required to prevent wind-driven rain from entering the roof system. This ensures adequate overlap between adjacent tiles in the same course.
Why the other options are wrong
- A. 2 inches of side lap is below the recommended minimum for most tile types.
- C. 1 inch side lap is insufficient for tile roofing and would lead to leaks.
- D. 4 inches of side lap is more than typically required and could affect the tile's appearance or installation efficiency without additional benefit.
Tile Side Lap
Side lap refers to the overlap of one tile over an adjacent tile in the same course, measured horizontally.
- Prevents lateral water intrusion.
- Critical for wind-driven rain protection.
- Typically 3 inches for most tiles.
Memory trick: Side-by-side, tiles need a triple lap to thrive.