Two garments can use the same fabric and look identical in photos, yet feel completely different to wear. Construction is often the reason. The seams and stitches you choose affect comfort, stretch, durability and how premium a garment feels.
Key takeaways
- Knit garments need stretch stitches such as overlock, coverstitch and flatlock; wovens use lockstitch and flat-felled seams.
- Taped necks, twin-needle hems and bar tacks are small details that signal quality.
- Call out key seams in your tech pack and check them on a washed sample before bulk.
Common seam and stitch types
| Type | What it is | Typical use |
|---|---|---|
| Overlock (serged) | Joins and finishes edges in one pass, stretches with knits | T-shirts, hoodies, knitwear |
| Coverstitch | Parallel stitches on top, looped underneath, stretchy hem | Tee hems, sleeve hems, activewear |
| Flatlock | Flat seam with no bulky ridge | Activewear, base layers |
| Lockstitch (single needle) | Straight, neat stitch for woven fabrics | Shirts, topstitching |
| Flat-felled | Raw edges enclosed and double stitched | Jeans, workwear, shirts |
| French seam | Raw edges enclosed inside the seam | Lightweight and sheer fabrics |
| Bound seam | Edges wrapped in binding tape | Jackets, unlined outerwear |
Seams for knits vs wovens
Knit fabrics used for t-shirts, hoodies and leggings stretch, so they need stitches that stretch too: overlock, coverstitch and flatlock. Woven fabrics used for shirts, pants and jeans do not stretch much, so lockstitch and flat-felled seams are common.
Details that signal quality
- Taped necklines on tees and hoodies for comfort and shape.
- Twin-needle hems for a clean, durable finish.
- Bar tacks at stress points like pockets and belt loops.
- Consistent stitch density, often noted as stitches per inch.
- Flat seams in activewear to prevent chafing.
How to specify construction
In your tech pack, add callouts on the flat sketch for key seams (side seams, shoulders, necklines, hems) with seam type, stitch type and any finishing. If you are unsure, reference a garment you like and ask your manufacturer to match its construction.
Check construction on your sample
Look at seams inside and out, stretch them gently, and wash the sample. Check for puckering, skipped stitches and uneven hems. Our sampling guide has a full checklist.
This is part of our cut and sew series. Start with what is cut and sew manufacturing, then read our trims guide.
More in our Cut & Sew guides
Frequently asked questions
What is the most common seam in t-shirts?
T-shirts are typically joined with overlock (serged) seams and hemmed with a coverstitch, which stretches with knit fabric.
What is a flatlock seam used for?
Flatlock seams lie flat against the skin, which reduces chafing. They are popular in activewear and performance garments.
Which seams are strongest?
Flat-felled seams, common on jeans and workwear, are among the most durable because the raw edges are enclosed and stitched twice.
Do I need to specify seams in my tech pack?
Yes for important details. Specify seam and stitch types for key areas such as side seams, hems and necklines, and note stitches per inch where it matters.
Making an original garment?
Our cut and sew team can recommend construction for your fabric and use. Quote within 24 hours, from 50 pieces per design.
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