Acceptable fastening methods:
Nails:
- 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.
Screws:
- Same as for nails. Also, #8 or larger screws required.
Clips:
- Typically used in addition to other fasteners in high-wind areas. Requirements vary with jurisdiction and manufacturer.
Lug-hung
- 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.