Rain Jacket and Raincoat Manufacturing Process

The word waterproof is used loosely in apparel, and rainwear is where that vagueness becomes expensive. A jacket can be made from a coated fabric and still leak through its shoulder seams within minutes. This page sets out what actually makes a rain garment work, what has to be tested, and where the honest boundary sits between water resistant and waterproof.

The distinction below is one instance of a wider discipline: a performance word only becomes a requirement once the property, the method and the acceptance criterion are named. That model is set out in apparel performance claims.

Water resistant, water repellent, waterproof

These three are not synonyms, and getting them right protects you commercially as well as technically.

Coated and laminated fabrics

Two routes produce a rain fabric, and they behave differently in production.

Seams: where rain jackets fail

Every stitch is a hole. A jacket cut from a fabric with excellent water resistance will still leak at the shoulders and hood if nothing is done about the seams, and that is a common failure in cheap rainwear.

• Seam sealing tape. A tape applied over the seam on the inside using heat, bonding to the coating or membrane and closing the needle holes. It is the standard solution and it requires a fabric whose back surface the tape can bond to.
• Fully taped or critically taped. Fully taped means every seam is sealed. Critically taped means only the most exposed seams, usually shoulders and hood, are sealed. Both are legitimate; the difference must be stated rather than assumed.
• Welded seams. Some heavy coated fabrics allow seams to be welded rather than sewn, removing needle holes altogether. It is a different production route with different equipment.
• Seam type. Seams intended for taping are constructed so the tape can lie flat, which restricts which seam types can be used.
• Tape adhesion. The tape has to be applied at the correct temperature and speed for the specific fabric. Poor adhesion peels away in service, and it is checked on the sample rather than trusted.

Hood construction

The hood is what makes a rain jacket usable, and it is a part often built without enough thought.

• Peak or brim. A stiffened or wired peak keeps rain off the face. Without one, water runs onto the wearer's face regardless of how good the fabric is.
• Volume adjusters. A rear or side drawcord that pulls the hood closer so it turns with the head rather than blocking vision.
• Face aperture drawcord. Closes the opening around the face, with cord locks positioned where they can be used with one hand.
• Fixed, detachable or roll-away. A roll-away hood stows in the collar, which suits corporate and travel garments. A detachable hood attaches with a zip or studs, and both add construction.
• Coverage. The hood must cover the neck at the back, and the collar must sit high enough to close the gap when the main zip is fully closed.

Closures, ventilation and detailing

• Storm flap. A fabric strip covering the main zip, secured with studs or hook-and-loop. On a rain garment this is a functional part rather than a styling detail, since standard zips are not watertight.
• Water-resistant zips. Coated zips reduce water passage and are common on lighter rainwear. They are water resistant rather than waterproof, and on demanding garments they are used with a flap rather than instead of one.
• Pocket openings. Angled or flapped so they do not collect water, with the pocket bag positioned so water does not sit inside it.
• Cuff adjusters. Hook-and-loop tabs or elastic to close the sleeve opening at the wrist.
• Hem drawcord. Closes the bottom opening so wind and rain do not drive up inside the jacket.
• Ventilation. Coated fabrics trap moisture from the wearer, so vents matter: mesh-lined body panels, underarm eyelets or zipped vents. Any vent is a deliberate opening, so it is positioned where rain will not enter.
• Lining. Mesh gives ventilation and a comfortable inner face; taffeta gives easier on and off; unlined garments are lighter and pack smaller. On a taped garment the lining also hides the tape.

Decoration on rainwear

Decoration is more restricted here than on most garments in this section, and for a good reason.

• Embroidery perforates the barrier. Every stitch is a hole through the coating or membrane, so embroidery on a waterproof panel compromises the performance it was bought for. Where it is required, it is placed on a non-critical area or on an applied patch, and the customer should be told what it means.
• Heat transfers. The usual solution, because they add a layer without perforating the fabric. Coated fabrics are heat sensitive, so temperature and dwell must be tested on the actual fabric before bulk.
• Printing. Possible on some coated shells and not others. Ask for a test rather than assuming.
• Reflective transfers and tape. Effective for visibility in poor weather, applied as heat transfer or stitched tape. Stitched tape reintroduces needle holes, so on a sealed garment it is usually heat applied.
• Branded hardware. Zip pullers, cord locks and stud finishes, which brand the garment without touching the barrier.

Assembly sequence

1. 1Fabric is inspected, including the coating or membrane surface, and cut with care not to crease coated cloth.
2. 2Decoration is applied where it has been tested and agreed, before assembly.
3. 3Pockets are constructed with their flaps and bags.
4. 4Body panels are joined using seam types that will accept tape.
5. 5Sleeves are set and the side seams closed.
6. 6The hood is assembled with its peak and adjusters, then attached, or the collar is built for a roll-away hood.
7. 7Seams are taped, fully or critically according to the specification.
8. 8The main zip is set with its storm flap; cuff adjusters and hem drawcord are fitted.
9. 9The lining is fitted where used, then labels are attached and the garment is inspected and tested.

Quality control and testing

If rain performance is contractual, put the test method and the pass level in the specification, and test the finished garment rather than only the fabric. Guidance on setting inspection and testing requirements is in the quality control guide.

What to put in a rain jacket tech pack

• Fabric: coated or laminated, base cloth composition and weight, coating or membrane type.
• Required water penetration performance, with the test method and pass level if it is contractual.
• Seam sealing: fully taped or critically taped, with the seams to be sealed listed.
• Hood: fixed, detachable or roll-away, with peak, adjusters and coverage.
• Main zip: type, whether water resistant, plus storm flap construction and closure.
• Pockets: type, opening angle, flaps and bag positioning.
• Ventilation: mesh lining, eyelets or zipped vents, with positions.
• Cuff and hem adjusters.
• Lining: mesh, taffeta or unlined.
• Decoration: method, artwork and placement, with a fabric test approved and any effect on performance acknowledged.
• Reflective detailing, and whether certification is required.
• Measurements with tolerances, including body and sleeve length for coverage.
• Packing, including whether the garment packs into its own pocket or bag.

Sampling

Test the sample with water. Put it under a shower or a spray rig with the zip closed and the hood up, and look for the classic leak points: shoulder seams, the hood seam, the zip, and the pocket openings. Ten minutes of that reveals more than a specification review alone.

Also check the hood with the adjusters closed and the wearer turning their head, and confirm that the collar covers the neck when the zip is fully closed. Both are comfort issues that turn into complaints in the field.