Luckily the Tesla contractor installing my panels were legit last year. They showed me the underlayment below the concrete tiles was paper thin and dry-rotted. The stuff was just flaking off every time they touched something and said they would absolutely not even install it until it was redone because it would be leaking immediately. They knocked $4k off the cost by paying them in cash, so an entire 1500sqft roof was redone for only $6k. Would have really sucked to get Tesla in here, install, and the roof that started leaking instantly. Still can't figure out why a builder like DR Horton would use such a crappy underlayment that didn't even last 15 years.