You can create a blouson valance by sewing together rectangles of fabric and lining, and then separating the back and front layers to create a puffy effect. Cutting your fabric and lining in 38-inch lengths will provide enough material to form two gathered rod pockets to encase a wider rod near the top and a slimmer rod near the bottom hem. A crisp fabric, such as easy-care cottons, plus a light lining will help support the gathers to give your toppers a distinctive profile. Before you start sewing, install two side brackets for the upper rod, plus two more side brackets for the lower rod approximately 7 to 8 inches below the top of the upper rod, to help support this blousy effect.
Measure with a tape measure the width of the installed rod from left to right and include the returns. For example, for a rod with a face width of 48 inches and brackets that project 3 inches from the wall, add 48 plus 3 plus 3 to calculate 54 inches for the rod width. Write down this figure.
Multiply this rod width by a fullness factor of 2.5 to calculate the fabric width needed to create the gathers. In this example, 54 inches times 2.5 equals 135 inches. Record this fabric width needed. Record 38 inches as the cutting length. This cutting length will be different from the finished length of your valance.
Bring your notepad and calculator to the fabric store. A label on the fabric end or on the bolt or roll will indicate the actual width of the fabric in inches. Divide the width needed by the actual width of the fabric to calculate the number of widths of fabric needed. For example, if the fabric width needed is 135 inches and the actual fabric width is 60 inches, divide 135 inches by 60 inches to calculate 2.25 as the number of widths of fabric needed. Record this number.
Multiply the number of widths needed by the cutting length of 38 inches to calculate the amount of fabric in inches. To calculate the yardage, divide this length by 36 inches. Round up to the next whole yard to allow for shrinkage and error. In this example, 2.25 times 38 inches equals 85.5 inches long. Divide 85.5 inches by 36 inches to calculate 2.4 yards and then round up to 3 yards. Record this as the amount of yardage to purchase. Purchase an equal amount of lining, preferably in the same width.
Place the laundered and pressed fabric on a large, flat surface. Trim off the selvages or finished sides with scissors or a rotary cutter and cutting mat. Mark with a yardstick and washable fabric marker or pencil the cutting lines for the 38-inch lengths. Cut the lining into 38-inch lengths. Set aside any leftover fabric.
Pin the widths of the fabric right sides together to form a wider panel that is 38 inches long from top to bottom.
Thread your sewing machine with color-matched thread and insert a universal sewing machine needle suitable for the fabric -- for example, a universal 70/10 needle for woven fabrics. Adjust the machine to a regular, straight stitch, such as a stitch length of 2.5. Test stitch on the scrap fabric to check for balanced, even stitches. Stitch a ½-inch seam to join the widths of fabric.
Press the seam allowances open with a preheated iron set to the temperature appropriate for the fiber content.
Pin the widths of lining right sides together to create a wide panel that measures 38 inches long. Stitch ½-inch seams to join these widths. Press open the seams.
Pin together the fabric and lining right sides together along the bottom and two sides of this wide panel. Leave the top edges of the fabric and lining open to allow for turning inside out later. Stitch a ½-inch seam along the two sides and lower edge. Remove every pin as the fabric feeds across the needle plate. You will see one line of stitching resembling a wide “U” with an open top end. Trim the lower left and right corners diagonally to reduce bulk. Take care not to cut the stitching.
Turn this panel right side out from the top end. Press the two layers together.
Adjust your sewing machine to a longer basting stitch such as a larger “4” stitch length value. Baste the upper layers ½ inch from the edges. You will see one horizontal line of basting across the top, from left to right.
Press under 5 ½ inches on the upper edge, lining sides together. Press under a ½-inch fold on the raw edge. You will see 5 inches of fabric in the top hem allowance. Adjust your sewing machine back to a regular straight stitch. Edge-stitch close to this inner fold.
Draw a horizontal line with a washable fabric marker 2 inches from the top of the panel to create a stitching guide. Stitch this line with a regular straight stitch to form a rod pocket and frill. You will see two horizontal lines of stitching near the top of the panel.
Fold up and pin an 8-inch inch hem from the lower end, with the fabric right sides together. You will see the face of the panel with 8 inches of lining at the lower section. Mark a horizontal line 2 inches from the lower end on the lining. Stitch with a regular straight stitch along this line to form a narrow rod pocket at the back and a bottom frill. Press this valance.
Insert the 2 ½-inch rod in the upper rod pocket, just below the frill. Insert the 1-inch rod in the lower rod pocket at the back of the valance just above the bottom frill. Ask a friend to help you raise and balance rods as you insert the upper and lower rods on the side brackets. Adjust the gathers evenly across the rods and then gently separate the fabric and lining layers to create the puffy effect for this blouson window treatment.