Fabric Files: Rib Knit

This content was originally written for Indiesew and has been adapted for this blog. It was originally published on April 5th, 2018.

I’m excited to share today’s Fabric Files post because I’ve been obsessed with rib knit fabrics for several months now. For years I was worried about how well they would wash and wear. I didn't own any rib knit garments and the substrate just seemed sort of flimsy and weird to me. But after sewing one garment in a rayon rib knit and seeing how well it held up after tons of washing and weekly wearing, I was immediately sold on this substrate.

So, today I thought it appropriate that we bring you a comprehensive resource to refer to when sewing with rib knit fabrics.

Rib Knit Fabric vs. Ribbing (Tubular) Fabric

First things first, and this is important, rib knits and ribbing are two VERY different types of fabric. The rib knits I'm referring to are intended to be sewn into entire garments, not to be used solely for neckbands, cuffs, and waistbands (though they will work for those purposes, too). They’re typically rayon or cotton blends and are a suitable weight for a fitted tee or dress. 

But there’s also a substrate called ribbing (it’s a very tightly knitted rib knit) that is sold specifically for the purpose of being sewn into neckbands, cuffs, and waistbands. Ribbing is typically 100% cotton. Sometimes it’s sold in tubular form, so that you don’t have to sew a seam into your neckband. Ribbing of this nature is not typically suitable to sew an entire garment in because it’s quite stiff.

Tubular ribbing is pretty nifty if you sew a lot of tees or sweatshirts, but this post does not apply to ribbing. In the future, if we do decide to offer ribbing, we’ll publish a separate Fabric Files post on that topic.

Rib Knit Characteristics 

If you knit, then you likely know the technical construction of a rib knit. A rib knit is a fabric that features raised vertical “ribs” knitted at regular intervals by switching between a knit stitch and a purl stitch.

If a fabric is listed as a 2x2 rib knit, that means that two stitches were knitted and then two stitches were purled to achieve ribs that are the same width as the “valleys” between the ribs. Rib knits can also have a 1x1 pattern where one stitch is knitted and then one is purled. This will result in a tighter rib knit that might not be noticeable from a distance. You may also see a 3x2, a 3x3, or even a 4x1 rib knit. The first number just refers to the number of rows knitted and the second number refers to the number of rows purled. 

The ribs of traditional rib knits run parallel to the selvage and create a very stretchy fabric, often with good recovery. Fitted designs like the Kila Tank are ideal for rib knits because they will cling to the body without stretching out.

Rib knit fabrics are typically made of cotton or rayon fibers, or a blend thereof. I like mostly rayon blend rib knits because they have a beautiful liquid drape and a very soft hand. I also find that rayon rib knits have better recovery than 100% cotton rib knits.

How to Sew with Rib Knits 

If you’re new to sewing with knits, it might be a bit nerve-wracking to sew with this super stretchy fabric. But following the tips below will result in stunning garments with very little effort! The most important thing you want to avoid is stretching out the fabric as you sew.

Using a Sewing Machine 

Along with using a stretch stitch and a ballpoint needle, I highly recommend using a walking foot on your sewing machine when sewing with rib knit fabrics. A walking foot will help to evenly feed the fabric through the feed dogs, preventing it from stretching out as you sew.

You may also want to decrease the foot tension so the fabric feeds evenly through the machine with little effort.

Using a Serger

If you’re using a serger to sew your rib knit fabric (which is my preferred method), you’ll want to treat it as a bulky knit fabric when adjusting your settings. I recommend increasing the differential feed setting to avoid stretching out the fabric as you sew. You may also want to increase your stitch width a bit. Below are the settings I use to serge rib knit fabrics:

Below is a photo of rib knit serged on different settings. You’ll notice that increasing the differential feed keeps the seam from being stretched out.

Use Knit Hem Tape

When hemming your rib knit garments, I highly recommend using a double sided adhesive tape like Soft Stretch by Heat N Bond. This product not only allows you to press the hem into place before sewing, it also gives the hem a bit more heft. I find that both my sewing machine and cover stitch machine produce a much neater hem when I use this product.

How to Care for Rib Knit fabric

Rib knit fabrics can be prewashed on a warm cycle and dried on a medium tumble dry cycle. But after sewn up, it’s highly recommended that you do not dry your rib knit garments in the dryer. If your rib knit fabric has any rayon content at all, it will start to pill after one or two trips through the dryer.

To prevent this, wash your garments inside out and then dry them laid flat on a towel to prevent stretching of the fabric. This will keep your rib knit garments looking new for many years!

How to Buy Rib Knit Fabric 

Rib knit fabric is becoming more readily available in most online fabric retailers and in some brick and mortar stores. Even better, it’s an inexpensive substrate usually ranging from $11 to $15 per yard. Rib knits that weigh anywhere from 7 to 9 ounces per square yard tend to be totally opaque, not needing a lining.

Pay special attention to the fiber content when buying rib knit fabric. 100% cotton rib knits will be stiffer, have less movement, and stretch out more than blended rib knits. Rayon rib knit fabrics will have the most movement and drape. Any rib knit fabric that has spandex in it will have superior recovery.

Garments Best Suited for Rib Knits  

There’s one big factor that you should consider when sewing with rib knit fabrics: size. Because this kind of fabric is incredibly stretchy (without a lot of structure), you may need to size down one or even two sizes to get the desired fit. Sew a muslin in some cheap rib knit to test your sizing. 

This is especially important for patterns that are designed for knit fabrics like jersey, but not for rib knits. Sizing down is not necessary for patterns that are designed for stretchy rib knits.

The Kila Tank shown below is sewn in a poly/rayon/spandex blend rib knit.

I hope this post was helpful in understanding a bit more about rib knit fabric and how it relates to garment sewing! Happy sewing!