You would really like to reupholster that mud-brown sofa that is too well-made to replace however, too ugly to live, but there’s a catch. The stations running up its tall back are daunting — it’s easy to picture replacing and removing the upholstery, however, the stations look like an insurmountable problem. They are not. Channels are actually not much more work than the simple upholstery job to get a straight-back chair or sofa. Collect your fabulous new cloth, your adhesive, knife and pliers, and send which mud-brown couch cover to the trash pile.
Remove the fabric to be replaced as you need for any re-upholstery job, saving the stuff to work with as a template to the new fabric. Inspect the padding used for the channels and replace it in case the batting, rags, foam or whatever formed the mold for the previous channels is worn, smelly, irregular or stained. Often, you will need to replace the cushioning to get the new channels even and resilient, so intend to do that.
Purchase upholsterer’s foam in a sizable piece a little thicker and broader than the old channel padding. You will have to choose a density or “provide” that feels great to you — foam comes from various densities, from soft to hard, exactly like pillow stuffing. High-density foam is much more resilient, feels elastic, cradles the body better and retains the shape of the channels longer with no getting fatigued. Lay the foam flat on your work room and find the midpoint of the piece.
Divide the foam to equal sections, measuring from the middle to the ends at top and bottom. Draw lines, using a yardstick, from the top points to the underside points to delineate every section.
Run a box cutter or craft knife down each line, using the yardstick for a guide, to score the splitting lines. Go over the lines you more time to deepen the cuts to approximately 1/2 inch.
Set the foam onto a bit of buckram or other closely woven backing fabric and cut the shape, leaving two inches across the top and sides and 6 inches or more across the underside. Glue the foam into the backing with spray glue, being careful to maintain the backing borders around the foam.
Trim the upholstery fabric into your large, single piece that is 4 inches wider than the foam and 2 additional inches for each channel. Cut the length, or height, to be at least 4 inches larger than the foam, but add an excess inch for each inch of foam depth. For 2-inch thick foam, by way of example, add two more inches to the length of the cloth. When in doubt, cut the bit bigger; you could always trim it afterwards.
Fold the width of the cut fabric in half, right-sides together. Slide the fold to the middle cut in the foam and pin it securely. Stretch the cloth gently above the foam into the next cut, tuck it in and pin it. Repeat until the upholstery fabric is loosely but effortlessly stretched and stretched into all the stations.
Sew a seam straight down every channel, through the upholstery fabric, the foam along with the attached backing material. Proceed with the rest of the upholstery job, fixing the channeled backing as one slice.