If your looking for the studs to mount your dish on your roof,  I have mine screwed into the Plywood and if it missed a stud i changed it to a bolt and went into the attic and put a nut and washer on it.  before i tightened it I put some clear silicone caulk into the holes.  And always mount it as low as you can  so it's over the Overhang instead of a interior room.