24 Jan 2023 • • by Heather Lou

How to Sew Double-Fold Bias Tape


For our first-ever pattern for Closet Core Crew, we've designed a beautiful quilted jacket called Parchment. Like most quilted jackets, Parchment is finished with double-fold bias tape along all the visible raw edges (and for some of the interiors seams as well, if you want to go whole hog!) We realized we've never done a blog post on the myriad ways to install this handy finish, which is nuts because we use it all the time. So... let's get into it!

What is Double-Fold Bias Tape?

Double-fold bias tape is essentially a long strip of fabric that's been cut on the bias (aka bias tape). It is then pressed by "double folding" the raw edges in to create a clean seam finish you can use to wrap your raw edges with (think of double fold bias like the book cover - the fabric you're wrapping it with is like the paper). Since it's cut on the bias, it has a bit of natural stretch built into it, making it easy to wrap around curves.

Double-fold bias tape can be made or purchased in many widths. The most common finished widths are 3/8" and 1/2". We suggest 3/8" tape for sewing most garments - it's narrow enough to finish necklines, seams, and arm openings, or for finishing the raw turned-up hem of a skirt. For quilts and quilted jackets, 1/2" tape is best since it's wide enough to sandwich thicker and bulkier fabrics, especially when you're dealing with quilt batting. While you can certainly use 3/8" wide tape to finish Parchment (especially if you're not dealing with a thick quilt sandwich), we visually like the look of a thicker tape since it gives the coat a bit more contrast.

The lovely thing about double-fold bias tape is that it looks great and protects your garments. Since you are completely wrapping your raw seam edges with it, you never need to worry about fraying. And if you don't have a serger (or want to make a gorgeous jacket inside AND out) DFBT can not only finish your seams, it can also give you the option to make a fully reversible garment. More on that in a minute!

How to Make Bias Tape

You can buy double-fold bias tape pre-made at Core Fabrics in lovely cotton poplin in both 3/8" and 1/2" widths here, but is also pretty simple to make and gives a lovely totally custom feel to your garment. It's also a great way to use up those odd 1/2 yard scraps of fabric you may have in your stash.

To start with, make sure you're using the right fabric. For the most stable tape, use thin fabric with a stable weave such as quilting cotton, poplin, or lawn. You can get fancy and make it out of viscose and silk too, just keep in mind slippery fabrics are a bit trickier to sew.

In order to make double fold bias tape, first you'll need to make simple flat bias tape. We have an easy tutorial here for how to make almost 9 yds. from 1/2 yd. of fabric! Once you have the bias tape cut, you can press it into the width you need with a handy bias tape maker. Keep your finished width in mind when cutting your bias tape - if you want 1/2" double-fold tape, you'll need to cut 2" wide bias tape to make it. For 3/8" wide tape, you'll need 1.5" bias tape to start.

How to Install Double-Fold Bias Tape

There are multiple ways to install double-fold bias tape depending on the final effect you're after (and how much time you have!) We have helpful tips that can turn a fiddly sew into a super smooth one, so now we'll show you three different methods to sew in double-fold bias tape and you can decide which one would work best for your application.

Sewing in One Pass

Though the quickest and most straightforward of the methods we're showing you here, this install takes a little more patience to set up. Rather than sewing the bias tape in a series of steps you are wrapping the tape around your raw edge and sewing it all in one go at your machine. This means while you have lots of control over how the finished, topstitched side looks, the other side will be a bit harder to predict. If you don't mind much what the wrong side of your project looks like you just need to ensure you've caught the underside in your stitching.

Wrap your bias tape carefully around your raw edge and pin it into place (wonder clips are also helpful here!) Some pre-made tapes have a slightly longer side. If that's the case, make sure that side is on the wrong side of your garment so you'll be sure to catch it when you topstitch it into place. Otherwise, stitch the tape in place about 1/8" away from the folded edge of the tape, frequently checking to make sure you're catching the other side of the tape in your stitching. If you miss a few spots don't fret - you can always go back with a hand sewing needle and slipstitch any bits that you may have missed.

Sewing in Two Passes

We almost always prefer to sew DFBT in two passes since it gives you more control. In the first pass of stitching, open the tape and align the raw edge of the tape with the raw edge of the garment. Pin or clip in place and stitch along the first fold to secure the tape in place. Now wrap the bias around the raw edge in a "quilt sandwich" and pin or clip in place from the other side. If your tape isn't laying flat, you may need to trim the seam allowance down so it wraps cleanly around. Once the tape is evenly wrapped around the seam, topstitch the bias in place 1/8" away from the folded edge to secure.

This advice is important: before you install your bias tape, think about the final application and what side will be most visible. The second pass of stitching when it is topstitched in place is the best-looking side - as a result, you want to make sure the most visible side of the garment is the one that gets that second pass of stitching. For example, if you're sewing a quilted jacket, you'll do your first pass on the wrong side of the jacket and then wrap the tape around the right side before topstitching it. This ensures you have a beautiful, even line of topstitching where it matters most. We often see instructions to start your bias tape on the right side of the fabric, but then you can't what you're doing while you topstitch it from the wrong side, which results in uneven stitching where it is most visible.

With all that said, whether it is the "right" or "wrong" side of the fabric merely depends on what side is MOST VISIBLE. In the jacket example above, the "right" side of the fabric will be most visible. However, if you are finishing a seam on the inside of your jacket and then pressing it open, the "wrong" side of the jacket will actually be the most visible since it is now pressed open. This becomes critical only when you're making a fully reversible jacket and need to make sure every visible seam looks its best!

If any of this feels confusing, always start by test-sewing a swatch first! If you're finishing your interior seams separately and pressing them open, sew two test swatches and then stitch them together so you can see what we mean by the most visible side!

Two-Pass Method by Hand

With this method, we are still sewing the bias tape in two passes, but the second pass of stitching is done entirely by hand. This means there is no visible topstitching which gives a gorgeous, couture-level finish. It also gives you the most precision and is the ideal technique if you're working with slippery fabrics like silk or viscose, or bulky fabrics wool.

With this method, you always want to start by installing the bias tape on the right side of your fabric. Just like above, open the tape and align the raw edges of the tape with the seam, right sides together. Stitch along the first fold to secure. Now wrap the bias around the raw edge in a "quilt sandwich" and pin or clip in place from wrong side. If your tape isn't laying flat, you may need to trim the seam allowance down so it wraps cleanly around. Once the tape is evenly wrapped around the seam, thread a hand sewing needle with a single thread and slip-stitch the bias in place along the entire edge, trying to make your stitches as invisible as possible.

Mitering Corners with Bias Tape

When it comes to turning corners with double-fold bias tape, it can be a bit tricky to get a super crisp corner. Here we'll show you how to get those sharp angles.

Open your tape and align the raw edges of the tape to the seam. Pin in place. At the corner where you need to turn, mark 1/2" from the edge (or 3/8" if you're using 3/8" wide tape) with a marking tool. Sew the bias tape in place with your first pass of stitching, stop at this mark, and backstitch to secure.

Fold the binding up at 45 degrees at the end of your stitching. The edge of the bias tape should align with the edge of the fabric.

Now fold the bias tape down again so the folded edge is aligned with the top edge of the fabric. The long edge of the bias should align with the remaining free edge of the fabric. Use pins to secure everything in place.

Sew your next pass of stitching starting at the folded edge, stitching along the folded edge of the tape. If you have another corner, repeat the previous step.

To finish, wrap the double-fold bias tape around the seam and to the other side. Press in each corner at 45 degrees and finish as desired by hand or machine.

How to Start and Finish

If you need to sew your bias in one continuous loop. this is how you do it so it looks so fresh and so clean. When you begin sewing the bias in place, leave the first 1/2" of bias free. As you return to where you started, fold the beginning edge of the tape in at a 45 degree angle.

Now extend the remaining bit of bias over this fold, extending past by at least 1/2". Sew in place to secure.

To finish, fold the bias to the other side and then finish in place by hand or machine.

Video Tutorial

If you're a more visual learner, we filmed this helpful video showing you each method step by step!

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How to Sew Double-Fold Bias Tape // Closet Core Patterns

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