Taped Seams
Taped seams are stitch lines sealed on the inside with a bonded waterproof tape, so water cannot enter through the needle holes.
Every stitch in a garment is a hole through the waterproof layer. A jacket made from 20,000 mm fabric with untaped seams will leak along its shoulders in sustained rain. Seam construction changes more real outcomes than the fabric rating does.
Fully taped, critically taped, untaped
| Construction | What it means | Use |
|---|---|---|
| Fully taped | Every seam sealed | Sustained rain, wind-driven rain, expedition use |
| Critically taped | Only the most exposed seams sealed, usually shoulders and hood | Shorter exposure, lighter garments, lower cost |
| Untaped | No sealing | Water resistant only, whatever the fabric claims |
Critically taped is a legitimate design choice on a light shell, but it should be disclosed. If a brand quotes a high hydrostatic head and does not mention seams at all, ask.
How to check
Turn the garment inside out. Taped seams show as a smooth strip of tape, usually 10 to 20 mm wide, running along the stitch line. Untaped seams show raw stitching. This takes about fifteen seconds and tells you more than the swing tag.
How it fails
Tape is bonded with heat and it degrades over years, particularly with repeated hot washing or tumble drying. Lifting or bubbling tape is the end of a garment's waterproofing, and it is usually not economically repairable. It is one of the reasons technical shells should be washed cool and air dried.
If the outer fabric still beads water but you are getting wet at the shoulders, look at the tape before you blame the fabric.
Related terms
- Waterproof and breathability ratings explained: why fabric numbers overstate garment performance
- Hydrostatic head: the fabric measure seams undermine
- How to wash a waterproof jacket: heat is what kills seam tape
- Glossary: all terms