CSLB C-39 Roofing ContractorSteep-Slope RoofingMedium

A roofer is installing a new clay tile roof system on a residential property. The tiles have a nominal length of 16 inches. To ensure adequate weather protection and allow for thermal movement, what is the typical minimum side lap required for standard interlocking clay roofing tiles?

  1. A1 inch
  2. B3 inches
  3. C2 inches
  4. D4 inches
Show answer & explanation

Correct answer: A. 1 inch

For standard interlocking clay roofing tiles, a minimum side lap of 1 inch is typically required. This overlap ensures that water is effectively channeled away from the roof deck while allowing for minor expansion and contraction.

Why the other options are wrong

  • B. 3 inches of side lap would be excessive for interlocking clay tiles, leading to reduced coverage per tile and increased material cost.
  • C. 2 inches of side lap is generally more than required for standard interlocking tiles and might be seen in extreme weather conditions or with specific tile designs.
  • D. 4 inches is far too much side lap for interlocking clay tiles and is not a standard requirement.

Clay Tile Side Lap

Side lap is the horizontal overlap of one tile over an adjacent tile in the same course, ensuring a watertight seam.

  • Prevents water penetration between adjacent tiles.
  • Crucial for weather resistance.
  • Typically 1 inch for standard interlocking clay tiles.

Memory trick: Side lap's narrow, but keeps the rain out.

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