A bed valance, also known as a bed skirt or dust ruffle, is a length of fabric that hangs from a box-spring mattress to the floor. It may be used to hide items stored under the bed, or simply to decorate the room as part of a bedding ensemble. The valance may lie flat or be gathered for a ruffled effect. These instructions are for a standard full-size mattress, but you may adapt this project for any size bed.
Cut the plain fabric into two pieces that are 37 inches long and 54 inches wide. Lay these pieces together with the right sides facing one another, and sew a 1-inch seam along one of the shorter sides. This fabric will be hidden between the top mattress and lower box-spring, so you can use the thread that matches the decorative fabric. Iron the seam open and flat. Hem one of the short ends for the head of the bed.
Measure the distance from the top of your box-spring to the floor. If you have a standard drop of 20 inches, cut the decorative fabric into seven pieces that are 45 inches wide by 22 inches long. If your drop is different, cut the pieces the length of the drop plus 2 inches. Lay two pieces together, right sides facing, and sew a 1-inch seam along the short side. Sew another of the seven pieces along the short side in the same manner, continuing until you have used all seven pieces to make one long, narrow valance.
Sew two lines of stitching along one long side, 3/8 and 5/8 inch from the edge. Use a ruffle attachment on your sewing machine to gather the ruffles, or use a long stitch with a regular sewing foot. Break the thread every so often, then start again a little before where you left off. This way you will have a continuous ruffle without having to gather it all at once. Hem the bottom edge of the long ruffle piece.
Pin the ruffle to the back of the bed-skirt top fabric so that 1 1/2 inches of the ruffle fabric meets up with 1 inch of the bed-skirt top. Pull gently on the threads of the ruffling stitches until the material is bunched up to meet the bed skirt's top edge. As you go around the edge bunching up the fabric, pin the ruffles in place.
Use the sewing machine to sew a 1-inch seam of the ruffle fabric to the bed-skirt top fabric, all the way around the bed-skirt top. Trim the seam to lie flat. Iron the bed valance and install on top of the box-spring, putting the straight edge at the head of the bed and letting the ruffles fall down on the sides and foot end.
When choosing fabrics, check for unravelling on the ends. If you find this, avoid the fabric.