I am building a small tool shed with 21x145 panel and 21x45 battens. When I make the doors for the shed, I wonder how I can make them as light as possible. Making doors out of paneling becomes very heavy. I'm considering using some kind of construction board on which I would then attach the battens. There will be two doors that are 550x800mm and two that are 500x1200mm.
Question: Which construction board can be used outdoors, can be painted, and is relatively lightweight, or is it better to make the doors out of paneling after all?