If the idea of replacing flat or damaged sofa cushions is cost-prohibitive, making your own is an alternative. Though it may sound daunting, this project is not difficult and requires basic skill with a sewing machine and minimal supplies. Making the cushions extends the life of your sofa and refreshes the decor of the room. Choose a durable fabric in a medium weight and upholstery foam to withstand the wear and tear that damaged the first set of cushions.
Determine the length, width and depth of the sofa cushion by measuring an old one and the seating area of the sofa. Add 1 inch to each measurement for seam allowances. Write down each measurement.
Sketch the cushion dimensions on a piece of paper to visualize the pattern and construction. There six pieces to consider: a top, bottom and four sides. A rectangle cushion has two short sides and two long sides.
Cut the six fabric pieces out of decorator fabric with sharp sewing scissors, using the adjusted measurements.
Sew the side depth pieces together to create a long strip that alternates the long and short pieces, using a sewing machine set to a 1/2-inch seam. Sew the ends of the strip together with a 1/2-inch seam to create a loop. Press the seams open with an iron.
Lay the bottom piece on a flat surface and pin a lapped zipper to one of the width sides of the fabric. Pin the matching length from the loop of fabric to the opposite side of the zipper. Sew the zipper to the fabric using a zipper foot on the sewing machine.
Pin the other three sides on the fabric loop to the bottom piece of fabric, with the right sides of fabric together. The corners on the bottom piece match to the seams on the loop. Sew the pieces together with a 1/2-inch seam. Open the zipper so you can turn the cover right side out after sewing.
Pin the four sides of the top fabric to the coordinating sides of the fabric loop, with the right sides of fabric together. The corners on the top piece match to the seams on the loop. Sew the pieces together with a 1/2-inch seam.
Turn the cover right side out through the zipper hole and smooth the corners with your fingers.
Mark the cushion measurements on the foam and cut it with a sharp knife. Slide the foam through the zipper opening and pull the zipper closed.