Shorten zipper bottom rather than the top.

Shorten zip from bottom

I have replaced quite a few zips over the years.  One of the more common reasons a zip will break is because it has been inserted using continuous zipping.  Or the zip was shortened from the top.  Both continuous zipping and shortening from the top means that the stopper at the top of the zip is not there.  This stopper ensures that the zipper will not run up into the fabric.  I have seen sliders that have come off because the top section was not finished completely, so the zipper flies off the end.

Shorten zipper bottom section ensures that the top of the zipper remains intact and workable.

It is very easy to shorten from the bottom.  Lay a strip of bias binding or fabric across the zipper at the position to be shortened.  Stitch across the zipper, sewing carefully over the teeth.  Cut the zipper and fold the bias or fabric around the zipper. Top stitch down.  This ensures the bottom will not unravel, or that it will rub against the body.

Here is a video I put together on how I shorten a zipper from the bottom.

Happy altering

Judith Turner