@genex5  fyi !
seems like a contractor  that will  leave you High and Dry .. 

and seem there is a promoter here  say how GOOD  this contractor is .
is this the service quality you expect ?
please DONT  recommend him again ... i will troll you . 

You've pretty much nailed the common reasons behind 'em:

Tiles go wonky from the wind, and rain sneaks in.
Broken tiles? Yep, they're like leaky gates for water.
That silicon seal on the galvanized sheet gets tired and starts leaking.
Those black waxy paper things in the roof's nooks and crannies? When they're torn, water finds its way in.
If you ever have roof troubles or want to prevent 'em, Mr. Alex from Master Roof is the go-to guy. Reach him at 018-3788226

Learned so much from him, and just want to support him as he was the one who settled my roof leaks and hope he can guide you to the same direction as well. haha.

i'm honored that you revived a 10-year old post