Seam Sealed
Construction — one of 70 in the glossary
A waterproof garment whose seams have been closed against water, usually by heat-bonding a tape over the stitch line on the inside. Every needle hole in a waterproof fabric is a hole, so a shell can be made of genuinely waterproof material and still leak through its seams — sealing is what turns a water-resistant garment into a waterproof one.
The seams are the weak point
A waterproof fabric stops water. A row of stitching puts several hundred holes per metre straight through it.
Under pressure — rain driven against a shoulder, a pack strap pressing on a seam — water finds those holes. A garment can be made of excellent fabric and still wet through at the shoulders.
Sealing is therefore not a refinement. It is the step that decides whether the garment is waterproof at all.
Fully sealed against critically sealed
Fully seam sealed means every seam is taped. Critically seam sealed means only the most exposed ones are — typically shoulders, hood and upper back.
Critical sealing is cheaper and lighter and is genuinely adequate for many uses. It is also the sort of thing a spec sheet states quietly.
If a garment is going to be worn in sustained rain, the distinction matters. For a shower, it does not.
What breaks it
Seam tape is heat-bonded, and heat is also what removes it. Pressing a decorated panel near a taped seam can lift the tape.
Embroidery through a sealed garment punctures the barrier afresh, and those holes are not sealed.
That is why decorated waterproof outerwear is usually printed rather than embroidered, or embroidered only on panels where a leak does not matter.
Common questions
- What does seam sealed mean?
- That the stitch holes along a waterproof garment's seams have been closed, usually with heat-bonded tape on the inside, so water cannot get through them.
- What is the difference between fully and critically seam sealed?
- Fully sealed tapes every seam. Critically sealed tapes only the most exposed ones — shoulders, hood, upper back. Critical sealing is lighter and cheaper and adequate for showers.
- Can you embroider a seam-sealed jacket?
- You can, but every needle hole punctures the waterproof barrier and is not sealed. Printing is the usual alternative on genuinely waterproof outerwear.
See also
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