bias bound and Hong Kong seam finishes

13 seam finishes to make your garment insides sing

We’re diving deep into one of my favorite topics today: beautiful types of seam finishes.

Here’s the thing: at some point in your sewing journey, you’ll start wanting to make the insides of your projects as pretty as the outsides.

It shouldn’t be your first sewing goal, but eventually dreams of bias bound seams will invade your thoughts. Weird but true. Also inevitable is the day you’ll come across a fabric that won’t play nice with a serger.

The truth is that there is no one-size fits all seam finish for every fabric.

So I’ll walk you through 13 different types of seam finishes, why you would choose each one, when to use them and which fabrics they’ll work best for. We’ll start with the easy ones and build up from there. My goal is that by the end you’ll walk away brainstorming different options for your next project.

Pinterest image: "how to make 13 beautiful seam finishes" bias bound seams

What is a seam finish?

Before we get into the types of seam finishes, what is a seam finish anyhow?

A seam finish is what you do to the raw edge of the seam allowances after you sew a seam. Seam finishes can use tools like pinking shears, specialized machines like a serger to create a special seam finish or different techniques of sewing or adding extra fabric that wraps around a seam to finish the raw edges.

Why do you need to finish seam allowances?

You’ll notice that many commercial patterns offer no suggestions or even list in your steps finishing the seams. So why do you need to finish seams?

    •to keep fabric from unravelling: fabric like linen and jacquard are notorious for raveling. If linings aren’t used with these fabrics, seam finishes MUST be used.

    •for extra strength: seam finishes like flat fell seams add strength to sleeve seams on men’s shirts and hard wearing denim.

    •for a decorative look: many seam finishes are sewn just for the beauty of them. Think of them as an opportunity to add something extra on the inside of your garment.

Some fabrics like knits do not ravel and aren’t 100% necessary to have finished seams. Still, go try and find a t-shirt in a store that doesn’t have finished seams. You won’t find one.

The truth is that finished seams just look better on the inside of a garment. Is it extra time to finish your seams? Yes. Is it worth it? Also, yes.

4 Simple seam finishes

These are the seam finishes that won’t require much extra work on your part. They’re quick and won’t require any special machinery or techniques. Simple is simple, and these 4 types of seam finishes are just that.

Pinked seams

If you have grandmothers who sewed, you’ve probably seen this finish. All you do is either press a seam open or to one side.

pinking shears vs. pinking rotary blade

Next, with a pair of pinking shears, trim the seam seam allowance. The pinking shears will make a dead easy bulk free finish. Instead of pinking shears, you can also use a rotary cutter with a pinking blade. Here’s how the two fare against each other in rotary cutter vs. scissors.

When to use pinked seams

  • Lightweight wovens like cotton voile or batiste
  • Sheer fabrics that you don’t want to weigh down with thread
  • Things you won’t wash a lot: even though the pinking will cut down on the fraying in the seam allowances, they will still fray a little over time. Things that are hand washed or generally washed gently will do better with pinked seams.

Zigzag finish

A Zigzag seam finish is a great multipurpose seam finish. You only need your regular sewing machine for it, and it’ll work for a variety of fabrics.

To make a zigzag seam finish, first sew a seam with your regular seam allowance. From there, sew a line of zigzag stitches close to the stitching line. You can sew it closer to the edge if you don’t want to trim the seam allowance, or you can trim past the zigzag stitching.

seam finishes on serger and sewing machine
zigzag on the donuts

The zigzagging will cut down on fraying without adding too much bulk. It’s a simple way to do a machine finish.

When to use a zigzag finish

  • If you don’t have a serger
  • When you have a serger but don’t want to rethread it to match colors!

Double stitched seam

double stitched seam on scuba

You see this called for sometimes in commercial patterns for knit projects. While most knits will not ravel, this can be a neat way to clean up the seam allowances.

I particularly like this for ponte and scuba knits.

To sew a double stitched seam, first sew your seam.

Next, sew a row of stitching close to the first. You can use a straight stitch or a narrow zigzag.

Trim away the excess seam allowance past the second row of stitching.

When to use double stitched seams:

  • For knits: when you want a minimal finish without serging. This is great for ponte, double knits, and otherstable knits.

Turned and stitched seam finish

It doesn’t get much easier than this one. For a turned and stitched seam, sew the seam, then press it open.

turned and stitched seam

Turn the seam allowances under and press. Stitch close to the pressed edge. This will keep the edges of the seam allowances clean and fray free. It’s a good alternative to more time consuming bias bound seams.

When to use a turned and stitched seam finish

  • Unlined jackets: as an alternative to bias bound or Hong Kong finish seams
  • When you want a clean, no fuss finish on light or medium weight fabrics

Serging and overcast seam finishes

This next round of seam finishes requires some specialty stitching. They’re similar to each other, but one uses your regular sewing machine or hand stitches.

Serger or overlock seam finish

This is the one seam finish that’s *almost* all-purpose. I say almost because there are some fabrics that do not do well with a serger. Sweater knits can get warped out of shape with a serger, and the stitching can be too bulky on some lighter weight fabrics. Thick, heavy fabrics often do better with other seam finishes, too. And don’t try to serge through sequins unless you really love breaking needles.

A serger (also called an overlocker) is a specialized sewing machine that stitches with 3-5 threads at a time to create a strong, clean looking stitch that encloses the raw edges of fabrics.

serged seam
serger seam on jersey

To serge with most fabrics, sew the seam, then run it through the serger. The serger will make a nice clean, professional looking finish on the edge. A knife on your serger will trim away any excess fabric as it’s running through the machine.

With knits, you can get away with using the serger to sew the seam and finish the edge at the same time. The serger stitch makes a seam with good recovery that’s perfect for knits.

With a couple setting changes, you can switch to a rolled hem which can be a good seam finish on fabrics like linen that fray easily.

When to use a serger

  • Speed: anytime you want a quick seam finish
  • Knits: makes a professional looking finish that’s suitable for almost all knits
  • To make extra narrow French seams: serger with a rolled hem for the first pass on a French seam + regular stitching can make an extra clean, teeny tiny French seam.

Overcast seam finish

An overcast seam finish is something you can use to finish seam allowances either by hand or by machine.

With your machine, you’ll have to switch feet. Machine overcast feet have a little guide to keep you stitching right on the edge of your seam allowance.

overcast seam finish

Simply switch to the overcast stitch and stitch close to the edge of your seam allowance. You can see how similar it looks to a serged edge.

You can also overcast a seam allowance by hand. Knot a single length of thread and work stitches that wrap around the edge along the length of a seam. This can be a nice minimal finish on delicate fabrics.

I also like to do a variant of a hand overcast finish on heavier fabrics. Press open the seam and work the overcast stitches. As you go along the seam, pick up 1 thread of the garment fabric every 1/2″ or so. This will anchor the seam allowance open and keep it flat. No stitches should be visible from the right side.

hand overcast seam

When to use an overcast seam finish

  • Something different: When you don’t want to serge or zigzag
  • Use hand overcast for a simple finish on delicate sheers or heavy fabrics like coating

Topstitched seam finishes

Sometimes you want your seam finish to be noticeable on the outside. These 2 finishes will get you there.

Basic topstitched seams

For a simple topstitched seam allowance, press open your seam allowance or press it to one side.

From the right side, stitch on either side of the seam. Take care to keep your stitching an even distance away from the seam. Because this is a visible seam finish, wonky, wandering stitching is going to be obvious.

You can use special feet like a blind hem foot to help you sew topstitched seams more accurately. Here’s how to topstitch and elevate all of your sewing now.

sweater fleece with topstitched seam
topstitched seam on heavy sweatshirt fleece

This is a great finish for heavy fabrics that you aren’t going to line. The stitching will keep the seam allowances flat and neat on the inside.

If you’re looking for a seam finish for wool, I would first try a topstitched seam finish. Wools can be thick and heavy, and a little topstitching can really help them stay flat and look sharp at the same time.

Exposed topstitched seams

This is a different kind of seam finish. It’s definitely has a specific look to it, but don’t knock it til you try it!

Sew your seams wrong sides together. Now all of your seams will be on the outside of your garment. From here, press the seams to one side and stitch through both layers.

exposed seam finish

The raw finish is nice on fabrics that won’t fray like knits. It’s something that you’ll see on ready-to-wear occasionally on more casual garments. It’s a fun finish. You can use a straight stitch or a zigzag depending on the kind look you’re going for. I once saw the coolest denim jacket with exposed seams that were zigzagged on the second pass.

Exposed topstitched seams are a decorative seam finish with a very casual and sporty vibe. Give them a try when you’re looking for something different.

Enclosed seam finishes

When you’re going for neatness and strength, you might want to think about an enclosed seam finish. Enclosed seam finishes all completely envelope the fabric of the seam so that it’s not visible from the right or wrong side.

In this category of types of seam finishes, you’ll find flat-felled seams which you’ll see on denim and men’s shirts as well as couture seam finishes like French seams and bias bound seams (almost identical to a Hong Kong seam finish).

Flat felled seams

You’ll see these on jeans and men’s shirts. Sew the seams wrong sides together. Next press the seam to one side. Trim the seam allowance on the under layer. Wrap the upper seam allowance around the trimmed edge and press again.

flat felled seam on twill

Stitch close to the pressed seam.

When to use flat felled seams

  • Men’s shirts: on the sleeve seams for extra strength
  • Denim: a classic finish for denim for keeping it strong and keeping it from fraying

French seam

This is a great enclosed seam finish for lightweight fabrics like silk and delicate cottons.

Because of the use of French seams on fine fabrics, they often get classified as a couture seam finish. That being said, that doesn’t mean they’re hard to sew. Let’s break it down.

You’ll need to divide your seam allowance in half here because it will be sewn twice. So if you’re sewing with a traditional 5/8″ seam allowance, the sew the first pass at 3/8″, and 1/4″ after trimming.

Sew the seam wrong sides together with a 3/8″ seam allowance. Press the seam to one side. Trim the seam allowance down to 1/8″.

rolled hem French seam step 1 and 2
French seam on silk, sewn first with a serger

After trimming, press the seam again to one side. Fold the fabric wrong sides together and press lightly on the seam. Stitch again with a 1/4″ seam allowance.

When to use French seams

  • Lightweight fabrics: silks, cotton lawn, batiste, voile
  • Sheer fabrics: makes a pretty finish that can be seen on both sides

Twill tape seam finish

It seems funny to think of twill tape as a seam finish, but it’s one you’ll see a lot on neck seams.

It’s because twill tape does a great job keeping neck edges from warping out of shape. That the tape keeps irritating seams away from your neck is bonus.

neckline on fleece top

To use twill tape to finish a neck seam, sew the seam as normal. Press the seam towards the neck. From there, lay the tape over the seam. Stitch through all layers close to the edge of the tape. This is a great finish for neck seams on hoodies.

Wrapped seam finishes

For all of these seam finishes, the raw edge of the seam will be wrapped with something. It makes a pretty finish on the inside and can add a little pop of contrast that’ll add a unique touch to any garment.

Bias bound seams/ Hong Kong finish

These are really similar finishes. For both finishes, sew the seams and press them open.

For a bias bound seam, next sew a piece of double folded bias around the edge of the seam.

bias bound and Hong Kong seam finishes
Bias bound seam left, Hong Kong finish right

To finish it off, stitch close to the top folded edge, making sure to catch the second layer beneath.

For a Hong Kong finish, cut a 1-1.5″ strip of bias from a lightweight fabric. Stitch the bias 1/4″ from the raw edge. Next wrap the bias around the edge to the wrong side of the seam. Stitch in the ditch from the right side to catch the underlayer of bias. You can trim away the excess bias.

You can see how similar they look. The Hong Kong finish is slightly less bulky since there’s one less layer of fabric.

When to use bias bound seams or Hong Kong finish

Because bias bound seams/Hong Kong seam finish require a lot of extra sewing and materials and have an extremely decorative look in the end, this type of seam finish gets called a couture seam finish. It’s a sign of great craftsmanship to open up a coat with this type of seam finish.

  • Unlined jackets and coats: adds a beautiful contrast on the inside of a jacket. Perfect for heavy fabrics or fabrics that fray when you look at them like brocade.
  • You can use packaged tape for bias bound seams. Hong Kong finishes work best with bias cut from lightweight silks and cottons.

Foldover elastic

Foldover elastic can work much like a bias bound seam. It’s a nice way to finish soft shell fleeces which can have irritating edges to them.

Sew the seam as normal, then press it open. Wrap the elastic around the raw edge of the seam along the fold. Stitch close to the fold with a straight stitch or a 3 step zigzag.

fleece seam allowance finishes

As a variation of this, sew a seam, then cover it with foldover elastic, stitching on either side to anchor the elastic down.

Use foldover elastic for seam finishes on heavy activewear knits like polar fleece and softshell.

I’ve used this type of seam finish on a soft shell jacket. Soft shell has rough edges that can be irritating on hands, but the soft foldover elastic covers over everything and works well with the soft shell’s knit backing.

As a bonus, you’ll have pretty decorative elastic on the inside of your garment!

How to choose the best seam finish

If you want to pick the best seam finish for a fabric, I have two quick thoughts.

  1. Test!: You will never go astray if you do a little sample test. If you want to try out a couple different seam finishes, a quick sample will help you see what a finish will be like on the finished product. Plus, you’ll save yourself headaches later!
  2. Check a reference: If you’re not sure about a fabric, check a reference book. One of my favorite books, Fabric Savvy by Sandra Betzina has some excellent advice on seam finishes for nearly every fabric.
sheer seam finish on yellow embroidered organza
self-bound seam on sheer organza: Hong Kong was too visible and French seams were too heavy with the embroidery. Testing was the only way to find the best choice!

So there are 13 different ways you can finish a seam. Whether you go simple or something a little fussier, in the end there’s a lot of different choices to explore. Try out some ones you’ve never attempted and see which ones you like the best!

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