The top (cream) is a heavy cotton canvas. The sides and bottom (blue) are nylon canvas, with a sealing layer. I put a piece of felt on the foam, under the cotton.
Cut the mattress into 3 pieces: two will be the couch, and the third will be used in the reading nook. All three will be used as a bed. I also got some perfect fabric to upholster it with.
Working on the couch/bed. Next step, I'll save for another day: cut the foam into three pieces. And then I'll need to sew upholstery for those pieces...