Casing seam (drawstring tunnel)
Also known as: Drawstring casing, Tunnel seam
Two parallel stitch lines forming a fabric channel through which a drawstring, elastic or drawband is threaded — classic in hoods, sweatpant waists and drawstring bag closures.
Description
The casing seam — often simply called a casing in pattern-making — is a functional seam type where the fabric is folded and stitched with two parallel rows of stitching to form a continuous channel. A drawstring, elastic or drawband is threaded through this channel to regulate width or close the garment.
Two basic construction variants exist: The simplest is the double hem casing, in which the fabric is folded twice and secured with an inner topstitch (forming the channel top) plus an edge topstitch (forming the channel bottom). The second variant is an applied casing: a separate fabric strip (2–3 cm channel height) is placed on the outer fabric and stitched around all edges. In hoods the casing sits along the front opening, in sweatpants at the waist, in backpacks at the top closure. A cleanly positioned eyelet cut or metal grommet at the exit is essential — this point defines the pull direction and must be reinforced so the fabric does not tear.
- Construction: two parallel stitch lines about 15–30 mm apart
- Applications: hoods, trouser waists, cuffs, backpack closures
- Accessories: drawstring/elastic + cord stopper + eyelets (plastic/metal)
- Load: exit eyelet must be reinforced with interfacing or rivet
Properties
| Construction | Two parallel stitch lines, 15–30 mm apart |
|---|---|
| Variants | Double hem or applied strip casing |
| Application | Hoods, trouser waists, cuffs, backpacks |
| Critical point | Reinforce exit eyelet with interfacing or rivet |
Related product categories
Sources & references
2- Sewing Glossary: Casing seams sewguide.com https://sewguide.com/
- Colette Sewing: Casing tutorial blog.colettehq.com https://blog.colettehq.com/
