Different Types of Knit Fabrics

Knit fabrics breathe, stretch, and move—making them a favorite for garments that live on the body. But not all knits behave the same. I once cut a sleeve out of a sweater knit, only to realize too late it had 70% crosswise stretch—resulting in a wavy, misshapen seam. That mistake taught me to respect the structure beneath the drape.

Understanding the subtle differences between knit types isn’t just about choosing the right fabric—it’s about anticipating how it will react under the presser foot, over the serger, and after the first wash.

Understanding Knit Fabric Structure

Knit fabrics are constructed by interlocking loops of yarn, unlike wovens that use a perpendicular warp and weft. This looped structure gives knits their signature stretch and recovery. But the type of loop formation—how the yarn is fed, looped, and connected—determines everything from stability to drape.

How Knit Stitches Affect Performance

The two foundational stitches in knits are the jersey (or plain knit) and the purl. Jersey forms a smooth face with a slightly textured back—common in T-shirts. Purl stitches create a bumpy, reversible texture, often seen in sweater cuffs or textured knits. But in practice, most commercial knits are variations or combinations of these base structures.

I once mistook a double-knit pique for a stable interlock. It looked thick and firm on the bolt, but when I sewed a dress with a narrow hem, the edge curled aggressively. The issue? Pique has a looser stitch tension beneath a textured surface. It needed a twin needle and a bit of stay tape to stabilize the fold.

The Role of Yarn and Fiber Content

Fiber choice changes how a knit behaves, even if the stitch structure is identical. A cotton jersey will drape softly but may lose shape after washing. A polyester-spandex blend with the same construction will rebound sharply and resist sagging.

At Pura Fabric, we’ve found that blends with 4–5% spandex offer the sweet spot for activewear—enough stretch for movement, enough recovery to hold silhouette. But beware: too much spandex in a lightweight fabric can cause stitching to pop under tension if the needle or stitch type isn’t matched correctly.

Common Types of Knit Fabrics

Each knit type brings its own rhythm to the sewing process. Some glide under the foot, others grip. Some press beautifully, others fight back. Knowing their personalities saves time, fabric, and frustration.

Jersey Knit

Single jersey is the most common knit—smooth on one side, ribbed on the back. It’s fluid, breathable, and ideal for T-shirts and casual dresses. But its asymmetry causes a quirk: it tends to curl at the edges, especially in cotton.

When cutting jersey, always pre-wash and dry it the way you’ll care for the finished garment. I learned this the hard way when a client’s dress shrank unevenly after laundering—because I’d cut it from unwashed fabric. Now, I pin my grainline meticulously and use a walking foot to prevent shifting during sewing.

Interlock Knit

Interlock is like two layers of jersey knitted together. It’s stable, doesn’t curl, and has moderate stretch. Because it’s balanced on both sides, it’s excellent for structured tops or children’s clothing that needs to hold up to washing.

I use interlock when I need a clean, professional hem without facing. But it can be deceptively thick for a twin needle—check your machine’s throat space first. On one project, my twin needle jammed halfway through a sleeve seam because the interlock was denser than expected. Switching to a serged finish saved the garment.

Rib Knit

Rib knits feature alternating raised and recessed rows—usually 1×1 or 2×2. They have excellent crosswise stretch and recovery, which is why they’re used for cuffs, neckbands, and waistbands.

The key to working with rib knits is matching their recovery. When attaching a ribbed neckline to a jersey bodice, I always slightly shorten the ribbing—about 85% of the neck opening. Then I ease it on with a stretch stitch. If you pull too tight, the fabric puckers; too loose, and the neck sags. It’s a tactile balance, learned through practice.

Ponte di Roma

Ponte is a double-knit fabric with a firm hand and subtle horizontal texture. It holds shapes beautifully—ideal for jackets, skirts, and tailored dresses. But its thickness can fool you: it’s stable, but still has 20–30% stretch.

Sewing ponte requires sharp needles—size 80/12 microtex—and a longer stitch length (3.0–3.5 mm) to accommodate movement. I once used a standard universal needle and a short stitch, only to find skipped stitches and puckering. Switching to a stretch needle and adjusting tension made all the difference.

Sweater Knits

Sweater knits vary widely—from fine gauge French terry to bulky bouclé. French terry has loops on one side, making it cozy and moisture-wicking. Bouclé, with its nubby, textured surface, is beautiful but tricky: the fibers catch on presser feet and needles.

When sewing French terry, I skip the iron and use a clapper to flatten seams. Heat can flatten the loops and ruin the texture. For bouclé, a tissue paper trick works wonders: place a sheet under the fabric to prevent snagging, then tear it away after sewing.

Spandex and Performance Knits

These include moisture-wicking athletic knits, swimwear lycra, and compression fabrics. They’re engineered for movement, so they demand precision in cutting and stitching.

Use a ballpoint needle and a narrow zigzag or lightning stitch. Straight stitches often break when the fabric stretches. For swimwear, I always pre-stretch the fabric slightly as I sew—just enough to prevent seam rippling later. At Pura Fabric, we carry performance knits with UV protection and chlorine resistance, designed for durability without sacrificing softness.

Mesh Knits

Mesh is lightweight, open-knit fabric often used for layering, linings, or sporty details. It’s sheer and slippery, so it can shift during cutting.

Pin, don’t weight, when laying out mesh. I once used fabric weights on a polyester mesh, only to find it stretched out of shape when I lifted them. Now, I pin every 4 inches and cut with small scissors for control. For seams, a three-thread overlock gives strength without bulk.

Specialized Knit Variants

Some knits defy simple categorization—engineered for specific effects or uses. These require extra attention to detail.

Thermal Knit

Thermal fabric has a brushed interior that traps warmth. It’s soft and cozy, perfect for loungewear or children’s pajamas. But the brushed surface can shed lint and clog your machine.

Clean your machine before starting, and use a fresh needle. I also reduce presser foot pressure slightly to avoid crushing the nap. When hemming, a coverstitch machine gives a professional, stretchable finish—though a twin needle works in a pinch.

Scuba Knit

Scuba is a thick, spongy polyester knit with a slight sheen. It holds dramatic shapes—think flared skirts or structured tops. But it doesn’t breathe, so it’s best for statement pieces, not everyday wear.

Because scuba doesn’t fray, you can leave raw edges on some designs. But if you’re sewing seams, use a 3.5 mm stitch and test tension on scraps. I’ve seen seams pucker when the upper tension was too tight, compressing the fabric’s loft.

Double Knit

Double knits are two layers interlocked, often made from wool or polyester blends. They’re stable, warm, and great for winter garments. Unlike single knits, they don’t curl and can mimic woven tailoring.

Despite their stability, they still stretch—usually along the bias. When cutting a double-knit coat, I align the pattern pieces with the grain and avoid bias cuts unless intentional. A size 80/12 needle and silk finish thread help prevent snagging on the smooth surface.

Handling and Sewing Tips for Knits

Working with knits isn’t just about technique—it’s about touch. You learn to feel the stretch, anticipate the recovery, and adjust as you go.

Choosing the Right Needle

Never use a universal needle on knits. Ballpoint or stretch needles have a rounded tip that slips between fibers instead of piercing them. I keep a needle gauge on my machine—swapping to a 75/11 ballpoint for lightweight jerseys and 90/14 for ponte or scuba.

Stitch Selection and Machine Settings

Knits need stitches that stretch. A narrow zigzag (1.0 mm wide, 2.5 mm long) works for most seams. For hems, a twin needle creates a professional double row with a zigzag underside.

If your machine has a lightning stitch (a curved straight stitch), use it—it stretches better than a standard straight stitch. I use it for side seams on activewear, where durability matters.

Cutting and Stabilizing Knits

Always pre-wash and dry knits, especially cotton blends. They can shrink up to 10%, distorting your final fit. When cutting, use sharp scissors or a rotary cutter—dull blades drag and stretch the edges.

For stretchy fabrics like rib knits or spandex blends, I sometimes spray a light starch alternative on the wrong side before cutting. It adds temporary stability without residue.

Preventing Common Sewing Issues

Wavy seams? Likely due to stretching the fabric as you sew. Let the feed dogs move the fabric—don’t pull. If the seam still waves, try a walking foot to equalize top and bottom fabric movement.

Puckered hems often result from tension mismatch. Test your twin needle setup on a scrap, adjusting upper tension until the bobbin thread doesn’t pull through. A bit of tissue paper under the foot can prevent feed dog drag on delicate knits.

Final Thought

Knit fabrics reward attention to detail. The way they stretch, recover, and drape changes with fiber, stitch, and even how you handle them on the cutting table. At Pura Fabric, we’ve seen how the right knit transforms a good garment into one that feels alive on the body. Choose with care, sew with intention, and let the fabric guide your hand.