Q: Why does zipper tape shrink after washing?
Tape shrinkage is normal within a range, and the problem starts when it differs from the shell fabric or exceeds the maker's figure. Measuring marked lengths at the intended care condition is the only reliable way to know which.
- Measure a marked length before and after a wash at the intended care condition.
- Compare with the maker's shrinkage data for the specific tape.
- Check wash temperature and drying method against the care label.
- Measure the shell fabric the same way to see the difference.
- Repeat for three to five washes to see whether shrinkage continues.
Shrinkage within the maker's range is expected, and the seam should be designed for it. Shrinkage well outside that range, or continuing after several washes, should be raised with the maker. The practical control is to wash a sewn sample before bulk cutting rather than to rely on a data sheet alone.