Stabilizing a knit shoulder seam

HelenBlackwood Cardigan, Blackwood Sewalong, Sewing Tutorials11 Comments

How to stabilize a knit shoulder seam

Stabilizing a knit shoulder seam

Stabilizing the shoulder seams in your knit projects can make a big difference in the longevity of your handmade garments. Shoulder seams are prone to stretching and sagging as time goes on, and stabilizing them prevents this.

There are a few things you can use to stabilize a knit shoulder seam:

  • Clear elastic
  • Twill tape
  • Woven fabric cut on the bias
  • Interfacing (with some stretch works best)

This is the second sewing step in the Blackwood Cardigan Sewalong

Let’s get started!

I will be using clear elastic, and I have coloured it blue in photoshop so you can see it. It was pretty much invisible, so I had to do something!

Start by laying out your project so the shoulder seams match up. You can sew the shoulder seams together before putting in the stabilizing tape, or do it in one fell swoop like I am.

Stabilizing a knit shoulder seam

Pin the shoulders and tape together.  I like to place mine on the front of the garment so that when the seams are pressed back, the elastic doesn’t get in the way. You may choose to use a thinner elastic or something softer, in which case you can put it on the back so it doesn’t show or press against the skin.  This is completely up to you.

Stabilizing a knit shoulder seam

Stabilizing a knit shoulder seam

Sew using a small zig zag stitch (accentuated with black below). Sew right through the elastic. It may be hard for the machine to get through the elastic. Try switching to a regular needle (they are sharper, so they can cut through the plastic). If backstitching is difficult at the ends, try leaving longer tails and tying them off. It will all be enclosed once we add the sleeves and neck band.

Stabilizing a knit shoulder seam

I finish this with my serger, but this is totally optional.

Stabilizing a knit shoulder seam

Stabilizing a knit shoulder seam

Press the seam toward the back of the garment to finish. Use a pressing cloth or press from the front side in order to avoid putting the iron on the clear elastic.

Stabilizing a knit shoulder seam

What is your favorite method for stabilizing a shoulder seam?  I remember the first time I tried this I thought it would bother my skin or make my shoulder bulky, but it does not get in the way. You see this method in higher quality ready to wear as well.

Tomorrow, we will be inserting our sleeves! See you then!

About the author


Helen Wilkinson is the designer and founder of Helen's Closet Patterns. She also co-hosts the Love to Sew Podcast! Helen is obsessed with all things sewing and strives to share her passion and knowledge with the sewing community.

11 Comments on “How to stabilize a knit shoulder seam”

    1. That’s a great idea! I find it hard to sew/serge on the clear elastic and was wondering if I can just glue it first before sewing. I’ll try your method of using twill tape or the selvedge strip.

      1. I have heard that some machines do not like the clear elastic at all, so in this case an alternative stabilizer might be the ticket!

  1. That’s a great idea, my machine keeps tearing the elastic tape when I use my lightening bolt stitch needed for knits. Thanks for the tip

  2. I realise I’m 3 years late to the party but do you think these methods would also stop the fabric from stretching while it’s being sewed? I recently made a knit dress from a rib knit fabric and the armscyes and sleeve cuffs got horrendously warped and stretched during sewing. I’m wondering if this method would help stabilise the fabric during the sewing process or if I should try something else. :/

    1. Hi Parizad! This kind of warping you are describing is quite common when sewing rib knits. It can be due to too much presser foot pressure, so try to let up on that pressure if your machine has a dial for that. A walking foot is also immensely helpful when sewing knits. Knit stabilizing interfacing can help, too! Sewing in elastic like this is an option as well. I hope you have better luck next time you sew rib knits!

  3. Hi if you use woven fabric cut on bias for stabilizing do you have to worry it will fray over time with raw edges? Thanks!

    1. Great question! Yes it will fray over time on the raw edges, so choose a fabric that frays very little or fold the bias fabric in thirds to make a tape that you can use without any raw edges exposed.

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