How do I replace a broken zip?

Replacing a zip is not technically difficult; it is an exercise in not losing the information about how the original was fitted. That is why the photograph and the careful unpicking matter more than the sewing.

What you'll need

• A replacement zip of the same type and length
• A seam ripper
• Pins or tacking thread
• A zipper foot, if using a machine

Step by step

1. Identify the zip type before buying.Closed-end for skirts, dresses and cushions; open-end for jackets and coats; invisible for dresses. They are not interchangeable, and an open-end zip in a skirt will not work.
2. Measure the tape, not the opening.Measure the existing zip from the top stop to the bottom stop. Buy the same length, or slightly longer — a metal zip can be shortened, a short one cannot be lengthened.
3. Photograph it from both sides first.Which side the pull sits on, how the top is finished, whether the tape is caught in the waistband. You will want all of this later.
4. Unpick, do not cut.A seam ripper under each stitch, working slowly. Cutting the zip out takes fabric with it and destroys the stitch line you need as a guide.
5. Press the seam allowances flat.The old fold lines are your placement guide. Pressing them crisp makes the new zip far easier to position accurately.
6. Tack the new zip in place.Hand tacking or fabric-safe tape. Pins alone shift as the fabric feeds, and a zip sewn 2mm off centre is obvious.
7. Check it opens and closes before sewing.Close the garment as it will be worn, check the seam lines match across the zip, and open and close the zip fully. Correcting now costs a minute.
8. Sew with a zipper foot.It lets the needle run close to the teeth. Sew down one side from the top, then the other side from the top as well — starting both from the same end stops the two sides shifting relative to each other.
9. Move the pull out of the way as you sew.Stop with the needle down, lift the foot, slide the pull past, lower the foot and continue. Sewing round the pull is what causes a wavy line.
10. Shorten a zip from the bottom if needed.Hand stitch a bar tack across the teeth at the new length, then cut about 2cm below it. On a metal zip you can also remove teeth with pliers.
11. Press and check.Press with a cloth over the zip, avoiding the plastic teeth with a hot iron, and test it fully.

Tips

• Photograph the original before you touch it. It answers every question you will have in an hour.
• Sew both sides from the top end. Sewing one down and one up twists the garment.
• Tack rather than pin. Pins move; a zip 2mm out is visible.

Common mistakes

• Cutting the old zip out — It removes the stitching line that shows exactly where the new zip sits, and usually nicks the seam allowance too. Unpicking takes longer and preserves the template.
• Buying by the opening length rather than the zip length — Zips are sold by the length of the closed teeth, not the tape. A zip bought to the wrong measure will be short at the top or leave a gap at the bottom.

If it doesn't work

Questions people ask