Originally Posted by goswick
The previous owner called every joint/seam possible on my '68 Airstream. I'm redoing the obvious places and wonder if it is necessary to seal the places where the aluminum sheets overlap. I've attached a picture example of the area I'm asking about.
I don't think so. Far more likely you'd be getting leaks at bad rivets than a lap seam in the aluminum, especially a horizontal seam lapped the right direction.
I suggest you seal around all the "stuff" on your roof (vents, antennas, etc), around the windows and doors, and check every rivet with a suction cup. Dig old sealant out as much as possible before putting down new.