I have learned from hard experience to prewash my fabrics. Not only for color shrinkage, but for dye issues. (I don't always buy the most reputable fabrics, and goodness knows what may happen if I don't prewash!) Recently I bought and washed some 108" backing fabrics, and was upset to have to figure out about pressing them afterwards. Was pretty pleased with my solution: I work on my "extra" dining table in the basement. I turned the vinyl table pads upside down so the felt was on top, covered the table pads with several old sheets that I clamped (Harbor freight stores sell several sizes of these) smoothly in place, and then got out the iron and pressed on my huge ironing table with a spray bottle for lightly spritzing the fabric. It worked out well. Good luck with your project!