Ohh really, most times it's the engineer that didn't use best specifications or maybe lack of maintenance because in this kind of situation of mine, the roofing sheet was removed and we then repainted it, if we don't do it like that we can't paint because it will still turn to that once rain falls.
But all those Building you mentioned in your comments,I have a remedy for them. They should abandoned the conduit pipe and run a surface own that can be control. So that there won't be leakage anymore..
Thanks for the comments and hope your day is going on cool and fine?