anything will work, as long as its flat, non reflective, and is pure white. like say you can paint a wall in your house primer white, and get it so its completely flat(no drywall bumps). there are even some "blackout blinds" you can get from home depot, for windows, they can get as big as 7 feet wide and 6 feet tall. but any projector screen should be tolerable as long as its made of a good, sturdy material.