A box-pleated valance is a formal window treatment that has to be sewn to the exact measurements of each window. Such a valance has a tailored look and works well with a heavy fabric or one with a formal pattern. With patience and care, you can make this beautiful addition to your decor.
Measure the window
The valance will extend beyond the window itself, so measure the width of the window, then add enough extra on both sides to determine the desired width of the final project. Measure how long you want the valance, typically one-sixth of the length of the window plus an inch or more for the part of the valance over the window.
Purchase a board for the valance
This type of valance is most typically mounted on a thick board that keeps the shape exact. The board should be about 2 or 2.5 inches wide and cut as long as the finished project. Measure how thick your board is, as the fabric needs to be long enough to cover the ends of the board.
Purchase fabric for valance and lining
The choice of fabric pattern is personal. However, this type of valance works best with a heavy fabric, such as home decorating fabric or a tapestry. Purchase plenty of fabric to account for seam allowances, the folds for the pleats, a hem and the sides of the valance that are attached to the board. The liner should be a thick fabric to help block out the sun and protect the integrity of your valance fabric.
Collect other needed supplies
You need measuring tape, pins, fabric scissors, thread, an iron, a staple gun and an L-shaped ruler. You also need a sewing machine.
Sew the valance
Sew the fabric and the lining together, right sides together. Then turn it right side out and top stitch around the entire piece. Iron the valence. Through trial and error, make two or three box pleats and adjust them until the width of the valance is correct. Once the pleats are the right size and pinned down, sew across the top of the pleat and then down both sides of the pleats to approximately 4 to 6 inches.
Staple the valance to the board
Using your staple gun and starting in the middle of the valance, staple the valance to the cut board. Staple it along the top of the board and to the sides to cover the board so you cannot see the board when the valance is attached above the window.
Hang the valance
Use brackets to attach the valance-covered board firmly above the window, making sure it is centered on the window opening. Steam the valance for a formal, pressed look if desired.