With the placemats I made recently I had the top, then one layer of batting, then one layer of pelment weight vylene, and finally the backing. The vylene is similar to the Timtex you use in fabric bowls/boxes, but it has no adhesive. I used the batting so that the quilting would show, and the vylene was to stiffen the place mats to stop them curling, and to help avoid any heat getting to my table top. I intended to make coasters the same, but ran out of time. I will get back to this project soon (perhaps).