For the backdrops I am using recycled material as much as possible. At the moment I have two different materials for the boards: foambord and honeycomb cardboard. Both are very light and easy to handle.
Foamboard is 10mm thick, a little soft from the inside.
The other board I use is called honeycomb board. It is 16mm carton with hexagonal inner cellular structure, which makes the board very strong but lightweight.
For the texture I use blaster, and mixture of leftover paints for the color.
Finish is waterproof, and it can handle very well all the mess and heat from the food.