What is Slub Fabric?

September 12, 2022
Nicole Rollender
Reaching for cream t-shirt on rack

Have you ever had a piece of clothing, like a t-shirt, tank or sweatshirt, that looked slightly lumpy? That t-shirt was probably made from slub fabric, a popular choice for t-shirts because slub fabric is lightweight, airy and doesn’t hug the body. Most often, apparel manufacturers and designers use either 100% cotton or a cotton/polyester blend to make the nubby slub cotton you see in lots of t-shirts, tank tops, sweatshirts, sweatpants, pajamas and other loungewear. 

If you’ve been wondering about slub fabric—what it is, how it’s made, how to care for it and how to decorate it—you’re in the right place. We break down everything you need to know about slub.

What’s Slub Fabric?

A “slub” is a section in a piece of yarn that’s thicker than the rest of the yarn length. At first, we considered slubs to be “mistakes,” since they result in a fabric with an uneven texture. That’s why spinners either “unwove” the slub from the yarn, or discarded that piece. However, apparel makers started to see that the slubs actually created a unique look in the yarn and fabric, and decided to intentionally weave these bumps into their fabrications. 

We’ll drill down into what slub fabric is even further, how to care for it, how to decorate it and where to find some affordable garments made of slub fabric. (By the way, people say slub or slubbed fabric, so choose the term you like best!)

What’s Slub Knit Fabric Made Of

Manufacturers create slub fabric by knotting and twisting yarn in different places and then weaving the yarn together. Most commonly, 100% slub cotton, cotton and polyester blends, and triblends are used to make t-shirts and tank tops. However, you’ll see tweed, silk and even butcher linen used to make slub fabric, but it’s not often a top choice to manufacture wholesale blank apparel.
You’ve probably seen lots of t-shirts, tanks and sweatshirts that have a nubby, heathered texture. They’re made from a slub knit fabric, woven from a yarn that has an uneven texture. The thicker parts of the yarn are called slubs, which make an irregular and interesting texture in the fabric. Plus, the slubs take dye differently than the rest of the yarn, resulting in that one-of-a-kind heathered look on the finished fabric.  

Like slub fabric, cotton and cotton blends are the most popular for slub knits, since natural fibers spin more unevenly and have more “slubs” than human-made fibers. Machine spinning reduces slubs, even in natural fibers, but manufacturers can also create more evenly spaced or “intentional” slubs, which create that wonderful visual effect in the fabric. This slub or heathered look also results in one-of-a-kind, worn-and-loved t-shirts and sweatshirts, even when they’re produced in bulk. When you add a decoration to one of these already-unique garments, you’re increasing the perceived value of the piece.

Shop Slub T-Shirts

You’ll see lots of high-fashion designers, as well as ready-to-wear fashion at retail and in the wholesale space, using slub fabrics to create trend-setting apparel with a vintage appeal. With our affordable collection of t-shirts and sweatshirts made from slub fabric, you can add a lot of personality to your wardrobe or the pieces you decorate to sell. Here are some Threadsy styles we recommend, since they’re great for decorating and wearing everywhere. After all, your new slub garment is your blank canvas for your creativity and self-expression.

  1. Ladies' Racerback Cropped Tank
    Bella + Canvas
    Ladies' Racerback Cropped Tank
  2. Adult 6 oz. Short-Sleeve T-Shirt
    Adult 6 oz. Short-Sleeve T-Shirt
    15% off with code POLO15 at checkout!
  3. Youth Heavy Cotton™ T-Shirt
    Youth Heavy Cotton™ T-Shirt

What’s Slub Fabric Used For?

As you’ve learned, slubs in yarn and fabric used to be considered undesirable or a mistake. Now, its popularity has exploded, and we’re seeing these slub-fabric styles on the runway, at retail and in the wholesale blanks industry, for screen printing and decorating. You’ll see slub styles most often for seasonal warm wear (like t-shirts and tanks) and comfortable layering apparel (like sweatshirts and hoodies).

The most popular slub knit items are t-shirts and tanks, which have a heathered or marled finish. The slubs add interest, dimension and tactility to the fabric. For comfy layering pieces, you’ll also see slub knit fabrics used for sweatshirts, sweatpants, pajamas and even t-shirt casual dresses.

Some apparel manufacturers do use silk to make slub fabrics, most often in formal wear. For example, high-sheen Shantung silk is a slub fabric that holds its shape. This “formal slub” can add interest to a gown or suit.

Caring for Slub Knit Fabric

If you’re new to buying slub knit fabric garments, it’s important to know how to wash and take good care of your slubbed fabric products.

How to Wash Your Slub Knit Fabric T-Shirt

Generally, for a regular slub knit cotton t-shirt, you’ll want to wash it with a delicate detergent in lukewarm or cold water on a gentle cycle. Washing your garments with care will help them stay vibrant longer.

How to Dry Your Slub Garment

It’s important to know that your slub knit fabric garment can shrink in the dryer, if it’s made from 100% cotton. Any 100% cotton garment that’s not preshrunk will often shrink if you dry it on high heat. If your slub fabric is blended with polyester or another human-made fiber, it’s less likely to shrink. That’s why we recommend that you always check the fabric label carefully to learn the right temperature to dry your new t-shirt or sweatshirt.

Some experts say the best (and safest from shrinking) way to dry your slub knit garment is to air dry it, so the fabric lasts longer and holds its stretch. However, you don’t need to dry slub garments wet from the washer. You can put your slub t-shirts in a quick tumble-dry session on low heat in your dryer, and then hang them to air dry while they’re slightly damp.

Pro Tip: If you tumble dry slub knit fabric frequently, it might stretch out or degrade faster and rip. The good news? If you accidently shrink a slub garment, you can wet it and then stretch it back to its original size and shape. 

How to Iron Your Slub Knit Fabric

Since slub knit fabric doesn’t wrinkle easily, you probably won’t need to iron it too often. Plus, ironing this delicate fabric could flatten and ruin the slubbed texture. If you do need to iron a slub t-shirt, use a press cloth and an iron on low heat. To keep your garment unwrinkled, fold and store it in a dresser or plastic bin.

Can You Screen Print On Slub Fabric?

If you’re a screen printer, you can absolutely decorate garments made of slub fabric, including 100% cotton, cotton/polyester blends and triblends. You can use both plastisol and water-based inks to screen print on slub fabrics. Some experts recommend mixing a soft-hand additive into your plastisol inks to maintain a lightweight, soft-hand feel on the t-shirt. 

To skillfully work with (and not against) the slub fabric, screen print designs with thinner lines vs. large inked elements. The simpler the design, the better. Aim for thinner fonts and elements that you outline, rather than fill in with ink. That way, you’ll allow for the unique fabric texture to enhance and add dimension to your screen-printed design. Plus, you’ll retain the airiness and unique feel of the shirt.

Pro Tip: You can work with a tonal effect by using a screen-printing ink that’s a shade darker or lighter than the fabric color. You’ll get a subtle, yet cool vintage look and feel.

You can also use heat transfer vinyl or dye-sublimation to decorate your slub knit t-shirts. Sublimation will result in a vintage or retro look, since you’d normally dye-sub on a 100% polyester garment. For example, you can sublimate a slub triblend, which has polyester in its blend.

The Skinny on Slub 

The reason why so many people love slub is because you can wear this soft, airy, comfortable fabric all year round. Get t-shirts and tanks in slub knit fabrics for the warmer months. Then, layer your slub sweatshirt, sweatpants or lounge shorts over your favorite slub shirts for maximum comfort in the colder seasons. Plus, when you decorate your slub t-shirts, you’ll create a unique, vintage look on an already one-of-a-kind shirt. 

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