Sewing a zip into a cushion cover takes about 30 minutes once you have the materials ready

A zip (or zipper) insertion is a seam that runs along one side of your cushion cover and holds a metal or plastic slider that opens and closes. You sew the zip between two layers of fabric before you join the other three sides. The zip sits flat inside the seam, hidden when the cover is closed, and lets you remove the inner cushion for washing or replacement.

The method works the same whether your zip is 16 inches, 20 inches, or any other length. You need a sewing machine with a standard presser foot, a zip foot (a special attachment that lets you sew close to the zip teeth), and a zip that is at least 2 inches shorter than the side where you want it. A 16-inch cushion cover needs a 14-inch zip; a 20-inch cover needs an 18-inch zip.

Key Takeaways

  • Buy a zip that is 2 inches shorter than the side of your cushion cover where you want it to sit.
  • Cut two fabric pieces to the same size, mark the zip placement on the seam allowance with a pen, and pin the zip face-down along that line.
  • Switch to a zip foot on your sewing machine, then sew the zip to both fabric pieces using a straight stitch close to the teeth.
  • After the zip is sewn in, fold the fabric right-sides together and sew the other three sides closed, leaving the zip open so you can turn the cover right-side out.

Gather your materials and prepare the fabric

You need two pieces of fabric cut to the finished size of your cushion cover (for example, 16 by 16 inches for a 16-inch cushion). Add a seam allowance of half an inch on all sides, so your pieces are actually 17 by 17 inches. A seam allowance is the strip of fabric between the edge and the line where you sew; it holds the seam together and keeps the cover from falling apart.

Press both fabric pieces with an iron to remove wrinkles. Lay one piece flat on your work surface with the wrong side (the side you do not want to see) facing up. Using a ruler and a fabric pen or chalk, draw a line half an inch in from one edge — this is your seam line. The zip will sit along this line. Mark the start and end points of the zip on this line with small crosses; if your zip is 14 inches long and your fabric is 16 inches wide, the zip will start half an inch from one corner and end half an inch from the other corner.

Pin and position the zip

Unzip your zip completely. Place it face-down (metal or plastic teeth pointing toward the fabric) along the seam line you drew. The top edge of the zip tape (the woven strip on either side of the teeth) should sit exactly on your drawn line. Pin the zip in place every 2 inches along its length, pushing pins through the tape and into the fabric underneath.

Check that the zip is straight by looking along its length; if it curves or twists, remove the pins, reposition it, and pin again. The zip should lie flat with no bunching. Once you are satisfied, you are ready to attach it to the first fabric piece.

Sew the zip to the first fabric piece

Remove the standard presser foot from your sewing machine and attach the zip foot. A zip foot is narrower than a standard foot and has a groove that lets the needle pass close to the zip teeth without hitting them. Thread your machine with thread that matches your fabric, or use a neutral colour like grey or tan if you have no exact match.

Position the fabric under the zip foot so the needle will sew along the edge of the zip tape, about a quarter inch from the teeth. Lower the presser foot and sew slowly from one end of the zip to the other, using a straight stitch at a medium speed. Stop and raise the presser foot if you need to reposition, but try to sew in one continuous line. Backstitch (sew backward) for a few stitches at the start and end to lock the thread.

Remove the fabric from the machine and trim any loose threads. The zip is now sewn to one side of the first fabric piece.

Attach the zip to the second fabric piece

Lay the second fabric piece wrong-side up on your work surface. Unzip the zip fully and flip the first fabric piece over so the zip is now facing up. Place the second fabric piece on top, aligning all edges. The zip should sit between the two pieces, with the teeth pointing toward the first piece and the tape visible on top.

Pin the second fabric piece to the zip tape along the same line where you pinned the first piece. Make sure the edges of both fabric pieces line up exactly. Sew along the zip tape using the zip foot, again about a quarter inch from the teeth. Sew slowly and keep the fabric straight. Backstitch at the start and end.

You now have both fabric pieces sewn to either side of the zip. Open the zip to check that it moves smoothly; if it catches or sticks, you may have sewn too close to the teeth. A small amount of resistance is normal, but the slider should move without force.

Sew the remaining three sides

With the zip open, fold the two fabric pieces right-sides together (the sides you want to see facing each other). The zip will be sandwiched between them. Pin around the other three sides, leaving the zip side unpinned. Make sure the corners are square and the edges line up.

Switch back to your standard presser foot. Sew along all three pinned sides using a straight stitch and a half-inch seam allowance. Start and end each seam with a backstitch. At the corners, stop with the needle down, lift the presser foot, turn the fabric 90 degrees, lower the presser foot, and continue sewing. This creates a neat corner.

Leave the zip open throughout this step. If you close it, the slider will be trapped inside the cover and you will not be able to turn it right-side out.

Turn the cover right-side out and finish

With the zip still open, reach through the zip opening and pull the fabric inside out, turning the cover right-side out. Push the corners out gently with a blunt tool like a chopstick or the handle of a wooden spoon so they are sharp and square. Press the cover with an iron, paying special attention to the seams.

Close the zip to check the fit. The zip should slide smoothly and the cover should lie flat. If there are puckers or wrinkles around the zip, they usually flatten after the cover is washed and dried.

Insert your cushion pad through the zip opening and close the zip. Your cushion cover is now complete and ready to use.

Frequently Asked Questions

What size zip do I need for my cushion cover?

Buy a zip that is 2 inches shorter than the side where you want it. A 16-inch cushion cover needs a 14-inch zip; a 20-inch cover needs an 18-inch zip. The zip does not need to run the full length of the side — stopping 1 inch from each corner is standard and looks neater.

Can I use a regular presser foot instead of a zip foot?

You can, but it is harder to sew close enough to the zip teeth without hitting them. A zip foot costs between £3 and £8 and fits most sewing machines. It makes the job faster and the seam looks more professional, so it is worth buying if you plan to sew more than one zip.

What do I do if the zip gets stuck while I am sewing?

Stop when ready and raise the presser foot. Do not force the zip. Check that you have not sewn over the slider itself. If the slider is free, lower the presser foot and try again slowly. If the zip is damaged, you may need to remove the stitches with a seam ripper and start over with a new zip.

Should I sew the zip before or after I join the other sides?

Always sew the zip first, before you join the other three sides. This lets you keep the zip open while you sew the remaining seams, which makes turning the cover right-side out much easier. If you close the zip before sewing the other sides, the slider will be trapped inside.

Can I wash a cushion cover with a zip in it?

Yes. Close the zip before washing to keep the opening sealed. Use warm water and a gentle cycle. The zip will last longer if you wash it inside-out, which reduces friction on the teeth. Dry on a low heat or air-dry to avoid damage to the zip slider.