Acceptable fastening methods:


  • Corrosion resistant
  • ¾” penetration. If roof deck is less than 3/4” thick, nails must protrude at least 1/8” from underside of roof deck.
  • Contact with pressure-treated lumber or coastal environment, hot-dipped galvanized or stainless steel recommended.


  • Same as for nails. Also, #8 or larger screws required.


  • Typically used in addition to other fasteners in high-wind areas. Requirements vary with jurisdiction and manufacturer.


  • May or may not require fastener installation

Adhesives and mortar are acceptable.

  • Sometimes inappropriate adhesives are used.
  • Mortar used to adhere clay tiles will fail due to differential expansion and contraction rates. Look for failure in cap tiles first.