I used a sheet of insulation board (4' x 8'..the kind that has silver metallic paper on the outside)....think it was 1 1/2" thick and covered it with flannel (used duct tape to secure it too the back). It was tall enough to wedge against the ceiling in our group's quilt room, so didn't have to secure it to the wall....actually we have 4 of these boards against one wall and we love em.