How to Finish Seam Allowances

Hey, you!

I believe with all my heart that a garment should be as pretty on the inside as it is on the outside.

And that means this…There are two steps to sewing with wovens:

  1. Sewing your seams; and
  2. Finishing your seam allowances.

In this article, you’ll learn why you need to finish your seams and a few basic ways to get the job done!

Let’s talk about the rules…

NOTE: If you’re ready to begin this journey and would like to buy my recommended tools and supplies, please click HERE!

Rules of Seam Finishes

Rule #1: You should finish your seams. That’s what professionals do.

Rule #2: You can use more than one seam finish in a garment.

Alright. Now that you know the rules, let’s talk about the benefits…

3 Benefits of Seam Finishes

There are three main reasons to finish your seams to…

  • keep fray happy fabrics from unraveling to nothing during construction or through the life of the garment;
  • add strength and durability to your seams; and
  • add beauty.

Okay, now that you know the why, let’s learn how to choose the right seam finish for the job…

Choosing a Seam Finish

The right seam finish depends on two things:

  • fabric weight; and
  • how fray happy your fabric is.

So if you’re ready, let’s finish our seams…

3 Basic Seam Finishes for Woven Fabrics

Stitched & Pinked

A hundred years ago, pinking seam allowances (SAs) was the seam finish of choice for the home sewer.

But today, even though we have so many more options, pinking your SAs on fabrics that are firmly woven and that is just a bit fray happy is still a great choice.

When you pink, those zigzag edges are cut on the bias. And the bias doesn’t fray!

There are two ways you can pink your SAs…

  • Sew your plain seam, and then just pink the SAs; or
  • Stitched and Pinked: first sew a line stitching ¼ inch from the raw edge, sew your plain seam. Pink both SAs at the same, and then press the seam open.

pinked seam finishes

Personally, I love the look of stitched & pinked! To me, it is just prettier! And it suggests that someone put an extra bit of love into the making of a garment!

Plus, it adds a bit more strength to the seam finish!

If you agree with me, here’s how you can stitch & pink like a master…

  1. Sew a stitching line ¼ inch from the raw edge of your seam allowances separately.
  2. Now, sew a plain seam. You’ll be pinking both SAs simultaneously.
  3. Next, place your garment on a flat surface and position your pinking shears so that the tip of the bottom blade in touching the cutting surface.
  4. Then, position the second sawtooth from the back of your pinking shears at the start of your seam allowances and to the right of the stitching line. And then, simply bring the blades together until they’ve almost closed.
  5. Now, open your shears and reposition them, lining up that same second back sawtooth with the last notch made.

how to use pinking shears

  1. Continue in this fashion along the entire length of the seam allowance.
  2. Once you reach the end, you can press the seam open.

Keep in mind that if the fabric is fray happy, pinking may only limit but not entirely stop the fraying!

Pro tip: If you’re pinking a delicate or lightweight fabric, you will need to place a scrap of stabilizer or a strip of tissue paper behind it before you begin.

Okay. Now that you know how to pink your seam allowances, it is time to get zigzaggy…

3-step (Multiple) Zigzag

While you could use a regular medium width zigzag stitch, I just love the 3-step zigzag stitch so much more.

Because it is so gosh darn attractive and easy to sew too.

And you know what…

I’ve rarely had issues with tunneling using the 3-step zigzag stitch.

If you’re pressing the seam allowances to one side, here’s how you do it…

3-step zigzag seam finish

  1. Sew a plain seam using the desired SA.
  2. Next, choose the 3-step zigzag stitch on your sewing machine. You can leave the setting as is. Or if you would like a more gently pointed zigzag, set the stitch length to 1.5mm and stitch width to 3.0mm.
  3. Then, align the raw edge of your SAs with the ¼ inch SA guide on the throat plate and 3-step zigzag along the entire length.  Do NOT backstitch!
  4. Next, with your embroidery scissors, trim as close to the zigzag stitching line as possible.
  5. Finally, press seam to one side towards the back of the garment.

Done!

However, if you will be pressing your seams open, you’ll need to do this…

  1. Choose the 3-step zigzag stitch on your sewing machine. You can leave the setting as is. Or if you would like a more gently pointed zigzag, set the stitch length to 1.5mm and stitch width to 3.0mm.
  2. With the right side (RS) of your SA facing up, align the right edge of your presser foot with the raw edge of your SA.
  3. Without backstitching, stitch a line of 3-step zigzag along the entire length.
  4. Repeat on the adjoining SA.
  5. Next, align the fabric with right sides together and stitch a plain seam.
  6. Finally, with embroidery scissors, trim as close to the zigzag stitching line as possible.
  7. Finally, press seams open.

Done!

Make sure to zig and zag as close to the raw edge as you can. And then trim the seam allowances.

RELATED: Click HERE to learn how to change your stitch length and stitch width!

Now, for my absolute favorite seam finish…

French Seam

If you want to hear a grown woman squeal like a five-year girl, whose favorite daddy has returned from a week-long business trip, then just let me discover this seam finish in a ready-to-wear (RTW) dress.

Yes, I did just that when I saw my very first French seam in a Belk’s Department Store. I was so bowled over that I lost my senses and bought a totally inappropriate dress because of it.

Here’s the thing…

The French Seam is rarely seen in RTW because it is double the work. But let me tell you this: It is worth it!

And this seam is not only sublimely pretty but mighty strong too.

I have had great success using it to sew lightweight, medium-weight, and sheer fabrics.

Anyhoo, let me stop gushing and tell you how to sew this seam finish so that you can experience its loveliness for yourself.

Here’s how you sew the ever lovely French Seam using a 5/8 inch seam allowance:

the ever lovely french seam

  1. Next, with the wrong sides of your fabric together, stitch a plain seam using a ¼ inch SA.
  2. Then, with your embroidery scissors, trim the SAs to ⅛ inch.
  3. Gently, press the SA to one side.
  4. Now align your fabric with right sides together, press, and then stitch using a ¼ inch SA
  5. Finally, press seam to one side towards the back of the garment.

Okay. Admit it. This is one lovely seam!

If you try this seam finish and fall in love with it as much as I have, then you will have to come back to this article and share the love in the comments section.

WARNING: When using this seam finish, do NOT snip notches in the SAs to transfer pattern markings; it will weaken the seam! Instead, use a marking pen or pencil.

Pro tip: There is also the little sister to the French Seam called the Mock French Seam. I love this for finishing curved seams.

What About Finishing Seams on Knits?

So glad you asked.

Because of how knits are constructed, knits don’t fray and unravel. So technically, you don’t have to finish the seam allowances of knits.

However…

If you want to press your seam allowances to one side or if you want to contain those madding cut curly ends of jersey knits, you’ll need a seam finish.

And while on many computerized machines there are many options, double stitching lines are simple, pretty and functional.

Here’s how you double stitch it…

double stitched seam finish

  1. Sew your first stitching line using a 5/8 inch SA.
  2. Next, sew a second stitching line using a 3/8 inch SA. This will give you two lines of stitching that are about a ¼ inch apart.
  3. Now trim as close as you can to the second stitching line.
  4. Finally, lightly press seam to one side towards the back of the garment. And you’re finished!

Now, how easy was that?!

The End

You are now in the possession of awesome seam finishing techniques for wovens:

  • the Stitched and pinked;
  • the 3-step zigzag; and, my all-time favorite,
  • the French seam.

And while knits don’t fray and, therefore, don’t require seam finishes, you now know a couple reasons why you might just want to and how.

Okay. With such simple options for finishing seams, there is no reason why your garments can’t look as pretty on the inside as they do on the outside!

Why?!

Because you deserve it!

And remember…

Life is the ultimate red carpet event. Dress for it!

RELATED: Click HERE to learn all the basic sewing skills you need to begin sewing insanely pretty dresses!

RELATED: Click HERE to learn about the plain seam!

RELATED: Click HERE to learn more about the zigzag stitch!

RELATED: Click HERE if you’re ready to begin this journey and would like to buy my recommended tools and supplies!

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2 thoughts on “How to Finish Seam Allowances

  1. I hate to be repetitive, but you are the living embodiment of COMPREHENSIVE. And a good writer who is also funny.

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