Sweatshirt Fabric: What It Is and How It Is Built
Sweatshirt fabric is a heavier knitted cloth, usually cotton or a cotton-polyester blend, with a smooth face and a looped or brushed back. The two classic versions are French terry, with unbrushed loops inside, and fleece, with those loops brushed into a soft pile. Both are weft knits made on circular machines, and both are chosen for softness, stretch and warmth. Understanding the knit behind the sweatshirt fabric explains most of what you feel and see in the finished garment.
This guide moves from the basics of knit structure to a table of the main types, then to ratings, weights, fibre choices and the faults to look for. It complements our overview of fabric types, which also covers wovens.
Types of Knit Fabric: Weft Knit vs Warp Knit
Knits divide into two families. In a weft knit, one yarn forms a row of loops across the width of the fabric, and each loop hooks into the row below. Single jersey, rib, interlock, French terry and fleece are all weft knits. In a warp knit, many yarns run lengthways and loop together in a zigzag, which makes a more stable fabric that resists running. Tricot and mesh are warp knits, more common in sportswear, linings and lace.
For casualwear you will almost always be choosing among weft knits. They stretch more in width than in length, they are soft, and they can be knitted as a tube, which avoids a side seam. They can also unravel or run if cut or snagged, and they curl at the edges in some structures, so finishing and cutting need care.
Knit Fabric Types Explained
The table lists the weft knits a brand is most likely to meet. Each row describes the structure, how it feels and where it is normally used, so you can match a fabric to a garment part rather than only to a garment.
Main knit fabric types
| Knit type | Structure | Handfeel and look | Typical use |
|---|---|---|---|
| Single jersey | One needle bed; flat face, textured back | Light, soft, drapes; edges curl when cut | T-shirts, hood linings, light tops |
| Rib (1x1, 2x2) | Vertical ridges on both sides | Very stretchy, springs back | Cuffs, hems, collars, fitted tops |
| Interlock | Two 1x1 ribs knitted together | Smooth both sides, stable, no curl | Premium tees, polos, light sweatshirts |
| French terry | Looped back, unbrushed | Smooth face, textured back; breathable | Sweatshirts, hoodies, joggers |
| Fleece (brushed back) | French terry loops brushed into a pile | Soft, warm, bulky | Winter sweatshirts, hoodies, joggers |
| Waffle | Grid of raised and recessed cells | Textured, insulating, lightweight for its look | Thermal tops, loungewear |
| Piqué | Small raised texture on the face | Textured, breathable, hides marks | Polos, tennis-style shirts |
Simplified descriptions of common weft knits. Many of these structures are made in several fibres and weights.
Rib deserves a separate note. Even in a sweatshirt made from fleece, the cuffs, hem and neck are almost always rib, because its stretch and recovery hold the garment against the body. The rib needs to match the main fabric in colour, fibre and shrinkage.
How a Sweatshirt Fabric Is Built: Loops and Brushing
The structure of a fleece-backed sweatshirt fabric is easier to picture as layers. A face yarn forms the flat outside, a binding yarn locks the layers and a thicker, loosely twisted yarn sits underneath as loops. Brushing is what turns the loop yarn into pile, and it is the last big step before finishing.
How a brushed sweatshirt fabric is made
- 1Choose yarnsSelect face, binding and loop yarns, usually cotton or cotton-polyester.
- 2KnitA circular machine forms a tube of French terry with loops on the back.
- 3Relax and dyeThe fabric is relaxed, dyed and washed so it settles into its finished size.
- 4BrushWire-covered rollers lift the loops into a soft nap if the fabric is fleece.
- 5Finish and testSoftener, anti-pill treatment and compacting are applied, then weight and shrinkage are checked.
Simplified sequence. French terry skips the brushing step and keeps its looped back.
Because brushing weakens the yarn slightly, a fleece usually pills more readily than the same fabric left unbrushed. That trade of softness against pilling runs through every choice in this guide.
Indicative Ratings: Five Knits Compared
The matrix rates five of the knit types on properties that matter to wearers and to production. It is indicative: the construction, yarn and finish of an individual fabric can move any score. It is best used to shortlist options for a given garment.
Knit fabric types on a five-point scale
1 dot = low, 5 dots = high
| Single jersey | Rib | Interlock | French terry | Brushed fleece | |
|---|---|---|---|---|---|
| Stretch | ●●●●● | ●●●●● | ●●●●● | ●●●●● | ●●●●● |
| Warmth | ●●●●● | ●●●●● | ●●●●● | ●●●●● | ●●●●● |
| Drape | ●●●●● | ●●●●● | ●●●●● | ●●●●● | ●●●●● |
| Pilling resistance | ●●●●● | ●●●●● | ●●●●● | ●●●●● | ●●●●● |
| Flat edges and stability | ●●●●● | ●●●●● | ●●●●● | ●●●●● | ●●●●● |
Indicative ratings based on typical fabric/process characteristics, not laboratory results.
The pattern is clear: the warmest and softest knit is the one most prone to pilling, while the most stable knit, interlock, is thin and less warm. Sweatshirt fabric sits in the middle, which is why it works so well for everyday wear.
Typical Weights of Sweatshirt Fabric and Other Knits
Knit structure and weight go together. Single jersey is the lightest, interlock and rib sit in the middle, and terry and fleece run heaviest. For a full explanation of how GSM is measured and converted, read our fabric GSM guide.
Typical GSM ranges by knit type
Typical ranges, grams per square metre
Typical ranges. They vary by product, factory and finish, so confirm the weight of any specific fabric.
A sweatshirt fabric between about 260 and 340 GSM is common for mainstream garments, with heavier weights used for premium or winter pieces. Always check weight on the finished, washed fabric.
Fibre and Blend Choices for Sweatshirt Fabric
Cotton gives sweatshirt fabric its soft, absorbent feel, and most premium sweatshirts use a high cotton share. Adding polyester, commonly around a fifth of the yarn in cotton-rich blends, improves shape retention, cuts shrinkage and reduces wrinkling. Fully polyester sweatshirt fabric exists but feels different and is better suited to sportswear, which sits outside our core.
Yarn type matters too. Combed ring-spun cotton gives a smoother, stronger face and less surface fuzz than open-end cotton, while organic cotton adds a sourcing story and sometimes a price premium. We compare fibres in cotton vs polyester, and the right blend depends on the garment, price and how it will be washed.
Elastane is rarely used in the body of a sweatshirt, but a small amount in the rib trims helps cuffs and hems keep their shape through repeated wear. If your design relies on a snug cuff or a fitted hem, ask the factory how much elastane the rib contains and how it recovers after washing. A rib with too little recovery bags out within weeks and makes an otherwise good garment look worn.
Finishes That Change Sweatshirt Fabric
Two fabrics with the same knit, fibre and weight can behave differently because of finishing. Compacting passes the fabric through a machine that pushes the loops closer together, which reduces later shrinkage. Enzyme or silicone washes soften the handfeel, and a garment wash after sewing gives the lived-in look many casual brands want. Each of these finishes changes the final size, so patterns should be cut with the expected change in mind.
Brushing and shearing alter the surface, and anti-pill treatment and softeners are applied last. If a sample feels excellent but the bulk feels harsher, the finishing route is the first thing to compare. Ask the factory to name each finish on the specification, so the same route is used for bulk as for the approved sample.
Write the knit structure, fibre blend, yarn type, finished GSM and finishing route on a single page, and attach the swatch. That page is what the bulk fabric will be checked against, and it protects both you and the factory if the bulk looks different.
Choosing Knit Fabric by Garment
Rather than choosing a knit in isolation, start from the garment and its parts. A hoodie might use brushed fleece for the body, rib for the cuffs and hem, and single jersey for the hood lining. The table shows typical pairings.
Typical knit fabric choices by garment
| Garment | Main knit fabric | Trims and linings | What to check |
|---|---|---|---|
| Hoodie | Brushed fleece or French terry | Rib cuffs and hem; jersey or self-fabric hood lining | Weight, pilling, hood shape, rib recovery |
| Sweatshirt | French terry or fleece | Rib neck, cuffs and hem | Shrinkage, neck stability, shade match of rib |
| Joggers | French terry or fleece | Rib cuffs; elastic waistband | Cuff recovery, abrasion, shrinkage |
| T-shirt | Single jersey | Rib collar | Yarn quality, edge curl, side-seam twist |
| Polo | Piqué or jersey | Knitted collar and cuffs | Texture, collar colour match |
| Loungewear set | Waffle, French terry or jersey | Rib trims | Softness after washing, matching top and bottom |
Common starting points only. The right choice depends on design, price and market.
For hoodies in particular, our hoodie fabric guide explains how French terry and fleece compare in the finished garment.
Common Knit Fabric Faults and What to Ask
Knits are forgiving to wear but can show faults that woven fabrics do not. Most are avoidable if you ask the right questions at sampling. The table lists the faults that cause the most disappointment, their usual cause and what to check.
Knit faults, causes and checks
| Fault | Usual cause | What to ask or test |
|---|---|---|
| Pilling | Short or loose fibres on the surface, especially in fleece | Martindale pilling test; named anti-pill finish |
| Shrinkage | Relaxation of the knit in the first washes | Shrinkage in length and width on your colour |
| Side-seam twist (spirality) | Yarn twist or poor relaxation of the knit | Wash a sample and check seams stay straight |
| Edge curl | Natural behaviour of single jersey | Cutting method and how the factory handles it |
| Shade variation | Different dye lots or rolls | Roll-to-roll shade control; one lot per order |
| Rib bagging | Rib without enough elastane or recovery | Stretch and recovery of the rib after wash |
General guidance. Test results depend on the exact fabric and test method.
Compare a washed sample against the approved sample as well as a new one. Many knit faults only appear after several washes. Our garment testing guide lists what to request.
How Ruhrose Approaches Sweatshirt Fabric
Ruhrose develops sweatshirts, hoodies, joggers and jersey garments for UK buyers, with production in Bangladesh. We agree the sweatshirt fabric, weight, blend and rib trims with you against a reference garment, then sample before bulk and compare the bulk to the approved sample. Flat-knit sweaters and technical performance knits are outside our core. For fabric questions on tees and polos, see what jersey buyers should check.