I covered my wood with one of those big black trash bags to avoid moisture in the wood. Then I put one layer of warm and natural batting. Then I added 100% cotton canvas and stapled each layer on the back. then I sprayed the canvas with water from a water bottle several times and the canvas shrunk and pulled really tight. My squares do not stretch when ironing. I had a cotton cover at one time, but it got ugly real quick. I love the canvas.