Understanding Seams and Garment Construction
By The Velocity Wear Team
A seam is simply where two pieces of fabric are joined, but the stitch used decides how much that join can stretch, how flat it lies, and where the garment fails first. On knitwear you are mostly looking at overlock seams, coverstitched hems and taped shoulders. Details like these tell you more about how a garment will age than the fabric weight printed on the label.
Why Stitch Choice Is Not Cosmetic
Jersey stretches. A plain lockstitch, the kind that holds a shirt collar or a pair of trousers together, does not. Sew a stretchy fabric with a stitch that has no give and the thread snaps the first time somebody pulls the garment over their shoulders. That is why knitwear uses stitches built from loops rather than straight locked passes: they extend with the fabric and recover with it.
It is also why you occasionally see a line of tiny broken stitches along a cheap sweatshirt's armhole. Nothing tore. The seam simply had less stretch than the cloth around it.
The Stitches You Will Actually See
Five constructions cover most of what turns up on custom apparel. Turn a garment inside out and you can spot them all in ten seconds.
- Overlock: the looped stitch that joins and neatens a raw edge in one pass. Fast, stretchy, slightly bulky, and used for side seams, shoulders and armholes on the majority of tees and sweatshirts.
- Coverstitch: two or three parallel rows on the face with a covering loop underneath. This is the standard hem on sleeve cuffs and body hems, and it lies flat rather than curling.
- Flatlock: butts two edges together instead of overlapping them, so there is no ridge against the skin. Common on sportswear and base layers where a bulky seam would rub.
- Lockstitch: the plain, non-stretch stitch used on plackets, pockets and woven parts of a garment, and for attaching labels.
- Chainstitch: a looped single-thread stitch still found on some hems and on denim, recognisable because it can unravel in a run if the end is cut.
Tubular and Side-Seamed Bodies
A tubular body is knitted as a continuous tube, so there are no side seams at all. It saves a cutting and sewing operation, which is why tubular blanks tend to be cheaper. The fit is boxier and straighter, and because circular-knitted fabric has a natural twist, tubular garments are the ones most likely to show spiralling side lines after a few washes.
Side-seamed bodies are cut from flat panels and joined, which costs more but lets the pattern taper through the waist and control the drop from shoulder to hem. If you are ordering a retail-fit tee, or anything you want to look considered rather than generic, side-seamed is worth the difference. For a one-off event giveaway, tubular is genuinely fine and nobody will complain.
Taping, and the Part Everyone Skips
Look at the inside of the back neck. On a well-made garment there is a narrow strip of tape running along the shoulder seams and across the back of the neck. That tape carries the load of the garment hanging off the shoulders and stops the shoulder seam stretching into a droop. It also keeps the neckline from going oval.
Untaped shoulders are the quiet reason a cheap tee looks tired after a month while a dearer one still hangs straight. Small material cost, very visible difference.
“"Nobody buys a t-shirt because of the shoulder tape. Plenty of people stop wearing one because it did not have any."”
Hems: One Row or Two
Single-needle hems use one line of stitching and are cheaper. They are more prone to roping, that slight twisted wave along the hem edge, and they give the fabric less to hold onto. Double-needle hems, the coverstitched ones, hold the fold more securely and resist the curling that single jersey wants to do at every edge. On sleeve cuffs in particular, a double-needle hem is what stops the cuff flipping up after washing.
Where Construction Meets Decoration
Printing needs a flat surface. A screen printing platen sits inside the garment, and anything that is not flat, a side seam, a hem fold, a zip, a placket, will lift the screen away from the fabric and leave a gap in the ink. That gives you a print with a pale band running through it. The same applies to heat-pressed DTF and vinyl, where a seam under the transfer stops the press making even contact.
The practical rule is to keep artwork clear of seams and hems by a comfortable margin, and to say so on the brief. If you want an oversized chest print running close to the edges, raise it before artwork is approved. Embroidery has its own version of the problem: stitching too close to a seam or over a folded edge causes puckering that no amount of backing will fully rescue.
What to Check on a Sample
Before committing to a run, turn the sample inside out and read the construction. Are the shoulders taped? Is the body side-seamed or tubular? Are the hems double-needled? Is the neck rib attached cleanly and covered, or is there a raw overlocked edge sitting against the skin? Then wash it and look again at the side lines and the hem. That catches most of what people later describe as a quality problem.
Velocity Wear works from a 20-piece minimum per order with sizes mixed freely, so it is easy to include a spread of sizes and see how a construction behaves before you scale up. You can lay out and preview placement in the free Design Studio, and the instant price calculator shows how garment, method and quantity move the cost.