In Arizona the most common tile systems are, sand cast, clay and concrete tiles. Most of what you see are concrete tile roofs. Most building codes call for one layer 30# felt with a 2” head lap. Even though the tile may last decades the underlayment usually last 15 to 20 years.
The 4 Top Reasons Why A Tile Roof Goes Bad:
1: Slipped, broken or missing tiles. This leaves the felt exposed to our desert sun and it will deteriorate causing it to dry out, crack and curl. Anyone walking on a tile roofs can break tiles, satellite installers, HVAC technicians, inexperienced roofers, etc.
2: Sloppy installation of the tile system. The installers went too fast not paying attention to critical detail areas at walls, skylights, valleys, chimneys and roof vents. Flashing details are one of the most vulnerable areas.
3: Deteriorated underlayment, remember there is supposed to be around 2” laps of felt, many times there’s not. So when the felt curl it exposes the decking. If water gets behind the tile and flows down, it may back up on the battens and get behind the felt into the building assembly.
4: Valley areas get filled with debris and when it rains the water can’t flow properly so it backs up beyond the valley metal usually following a batten and gets behind the flashing causing leaks.
Your actual tile should last a lifetime in Phoenix… it’s just your underlayment that’s the real issue.
Many property owners expect their tile roof to last a lifetime and are caught off guard when a roofer informs them they need a new roof. The concrete or clay tile usually can last a lifetime, but the underlayment won’t. For more information on tile roof repair visit: CostEffectiveRoofing.com