Originally Posted by nealtw
I guess the question has to be, what caused the damage that was found on the lower roof. Hate to argue with thirty years experience without hearing his argurment on not doing it. It sounds like most of the problem was over the exterior wall...
What cuased the damage that was found on the lower roof:
1) Water from upper roof with no gutter.
2) Water from overhang essentially breaking & starting to fall off.
3) Water seeping through old, neglected, broken & sometimes missing roof tile
4) Water seeping through old 30/90lb hot mopped underlayment due to all of the above.
1) The fewer holes in the roof the better.
2) Low profile venting options + hurricane wind driven rain = lots o' water in attic.
3) Experience or lack of proven local history with a particular product.