drip batten

I have a builder who has been working for me for a number of weeks and he has done a lot of work for me in the past. he is a jack of all trades, very handy guy and we have and receptive to my 'research'. Due to most of the the house being old and somewhat awkward he advised me to take the...

I am replacing an old flat roof. It is ply, but I am going to use 18mm OSB. Currently, the Fasica boards are nailed into the joists (fine ?), and also into the edge of the ply board. The drip edges (drip battens I think they are called), are also nailed "through" the top of the fasica boards...