What is the roof material wind resistance rating for concrete "s" tile?

Uplift resistance values are based on wind zone, mean roof height, roof slope, the particular fastening system proposed, as well as tile profile. Wind speeds to 150 mph are provided for within the context of this criteria. I am in escrow to buy a home here in Los Angeles that has one of your Lifetile roofs that was installed in 1989. Questions have arrisen about the proper underlayment for your tiles and because of leaks in the roof, I have concerns. It was installed by Pacific Roofing Co. What weight and type of membrane underlayment is recommended and is each tile supposed to be nailed down or just the first row? The minimum requirement for underlayments on roof slopes in excess of 4:12 would be a single layer of Type II asphalt saturated felt (No. 30). If the tiles are installed on battens, the first three courses should be fastened at all perimeter areas of the roof. Above 5:12 slope, alternate courses must be fastened in addition to the perimeter courses and above 12:12, all ...  more