Fixing a zipper on a jacket or a pair of pants is one thing, but when the zipper is on a sofa cushion, it gets more complicated. If you cannot repair the zipper yourself, you will have to opt for sofa cushion zipper replacement unless you want to buy a new cushion (or a new couch entirely). Hiring professionals to do this can be costly, and if the cushion is built into the sofa, you won't be able to remove it. Naturally, you will want to try fixing the cushion zipper first, and in some cases, this can be done quickly and effectively.
Sofa Cushion Zipper Replacement
If the cushion zipper is broken beyond repair, get a pair of pliers and remove the metal guards from both ends of the zipper. Slide the guards off, get a pair of scissors, cut around the zipper's attached fabric and remove the whole piece from the cushion. You can bring the zipper and material to a craft store. Buy one that is the same size and that matches the cushion.
You'll also need to buy upholstery thread and needles and replacement fabric to sew the new zipper onto the cushion. Turn the cushion inside out, tack down the zipper and put down the fabric on top of that. Sew in the new fabric, stitch hems and then sew the zipper into it.
Replace a Zipper Slider
If this sounds like a difficult sewing job or the zipper is fixable, you can instead try replacing its slider. These small parts work on different kinds of zippers, including those on couch cushions.
One example is the FixnZip, which attaches right onto the zipper's teeth. This gets tightened onto both rows of the zipper track and can get attached to any part of it. This sort of solution may or may not work depending on the type of zipper you have and the problems you are having with it.
Repairing Broken Zippers
If the zipper is facing the back of the couch and you aren't concerned with how the repair actually looks, you can try using permanent fabric tape to close the gap. You can also use upholstery thread to close it, keeping in mind that these two options make it much more difficult to remove the cushion if you ever need to do so. Of course, before you try any of these, there are some less invasive methods that might unstick that pesky zipper.
Get a bar of dry soap and rub it along both sides of the zipper's teeth until the surfaces feel slippery. Pull on the handle and see if the zipper works. If it does, run it back and forth a few times and then use a clean rag to remove any soap residue from the teeth when finished. A pencil can also work since the graphite in it serves as an effective lubricant. Use it as you would the soap. This is even better because unlike the soap, the graphite does not leave a residue.
The final solution for a broken zipper is Windex, of all things. You can spray it on the teeth and pull tab in an effort to fix the zipper. However, you should only use a squirt or two. Give it a few minutes to work and see if you can jiggle the stuck zipper back into working condition.