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How to: Seam finishes

Finishing a seam edge becomes essential to completing a garment. But how do you know which seam finish is best for the fabric or garment?

If you were to take a selection of garments from your wardrobe and turn them inside out, you would notice that all the seams have been finished in some way, most probably overlocked. Seam edges are finished for a number of reasons;

  • To provide a professional and neat finish,

  • To stop the raw edges from fraying,

  • Ensure that your garment will last wear and laundering, and;

  • To provide strength to the seams.

Therefore, finishing a seam edge becomes essential to completing a garment. But how do you know which seam finish is best for the fabric or garment? Here I will identify some of the most common seam finishes, when they are most appropriate, and how to achieve them.


A wrap-up of this how-to


Overlocked seams

The use of an overlocker (or serger) to finish a seam edge is probably the easiest, most common and professional method of finishing a seam edge.

An overlocker will often feature more than 1 needle, stitching multiple threads (usually 3 or 4) simultaneously, and trimming any excess fabric as you go. Overlocking is typically used for finishing the raw edges of seams together or separately as an open seam. However, this method can also be used to join the seams of stretch fabrics together. The specialised stitch created by the overlocker actually provides enough 'give' so that it can stretch with the fabric.

While overlocking is a neat and quick method of finishing any raw edges, there are a few things to be mindful of when using an overlocker.

  • Overlockers trim the edge of your fabric as you sew. Therefore, you need to be careful that you don't trim too much, or that your fabric becomes caught under the foot.

  • If you make a mistake, overlocking stitch can be time consuming to unpick.

  • Threading an overlocker from scratch is not fun, nor is getting the tension right. So I recommend getting to know your machine.

No overlocker?! No problem!

There are a number of different techniques you can use to help neatly finish the edges of your fabric, and stop them from fraying without the need for an overlocker. My only suggestion would be to test, test, test. Different fabrics have different properties and behave in different ways. Therefore, adjustments may need to be made to things like the stitch width and length, or the tension to suit your fabric.


Mock overlock stitch

Most domestic sewing machine these days will include a ‘mock overlock stitch’. My sewing machine has a few different variations, including seperate stitches appropriate for finishing stretch fabrics. It may be worth flicking through your machines instruction manual, or just having a play around!

The image above is just one of many types of mock overlocking my machine does.


Pinking shears

Pinking shears are essentially scissors that cut a zig-zag pattern into woven fabrics. The zig-zagging is what helps prevent the fabric from fraying. The use of pinking shears would be suitable as a seam finish for stable, tightly woven fabrics that aren’t prone to fraying, and that won’t be washed or worn a lot.

How to:
  1. Sew the seam with a seam allowance of at least 1cm.

  2. Press seams open.

  3. Cut close to the seam using the pinking shears.


Zig-zag stitch

While certainly not the most durable method for finishing seam edges, with the possibility of some fraying, zig-zag stitch is super simple and quick. The zig-zag stitch is also a common stitch option being available on most sewing machines. It is more suited to mid weight, more stable fabrics, as lighter weight fabrics may curl as the edge is pulled toward the bobbin.

How to:
  1. Sew the seam with a seam allowance of at least 1cm.

  2. Press seams open or together towards one side.

  3. Set your sewing machine to zig-zag stitch. Some machines will adjust settings accordingly, while others will require you to set this manually. For more heavier weight fabrics, opt for a larger stitch width and length setting, while for lighter weight fabrics, try a smaller setting.

  4. Sew around 5mm from the stitched seam allowance. Try to avoid sewing right on the raw edge as this may cause the fabric to curl.

  5. Trim close to the zig-zag stitch, removing excess fabric.


Turn under and stay-stitch

This method produces a relatively clean finish (possibility of some fraying) that is suitable for light to mid weight fabrics. This technique would not be suitable for sheer, or heavy weight fabrics that may produce bulk. It is also recommended that this technique be reserved for straight seams.

How to:
  1. Sew the seam with a seam allowance of 1.5cm.

  2. Press seams open.

  3. Turn under the raw edge of the seam allowance approximately 0.5cm.

  4. Press.

  5. Edge-stitch along the folded edges.


French seams

Despite being a little more time consuming, french seams are one of the nicest, and more durable edge finishes. The beauty of french seams is that the seam allowance is completely hidden. This technique is most suitable for light to mid weight fabrics, sheer or delicate fabrics, and those prone to fraying as the raw edges are entirely enclosed. It is recommended that this technique be reserved for straight seams, not working as well on curves.

How to:

You will essentially be sewing two seams for this method. Therefore, to determine the required seam allowance, simply divide your seam allowance by 2. For example, if your seam allowance is 1.5cm, you will be sewing 0.75cm for each seam.

  1. Sew wrong sides of fabric together creating your first seam.

  2. Trim away any excess fabric.

  3. Press to one side.

  4. Turn fabric so right sides are together.

  5. Pin, enclosing the raw edges.

  6. Stitch right sides together, creating your second seam.


Flat felled seams

This strong seam finish involves enclosing the raw edges inside the seam (similar to french), but it is pressed flat and stitched. Flat felled seams are visible from the right side of the garment, so can become a feature (e.g. stitching on jeans). This method is recommended for garments that are going to encounter a lot of wear and stress.

How to:
  1. Sew the seam with a seam allowance of at least 1.5cm.

  2. Press seams open.

  3. Trim one side of the seam allowance to 0.5cm. The side will depend on which side you want the extra row of stitching to be seen on the right side of the garment.

  4. Fold the remaining seam allowance in half, towards the seam.

  5. Press the folded seam over the trimmed seam allowance.

  6. Edge-stitch in place along the folded edge.


Bias bound seams

Bias bound seams provide a strong, and clean finish. Like french and flat felled seams, bound seams fully encase the raw edge within a binding. This method is great if you want to personalise your project, as you can use contrasting binding (just try to use a fabric with a similar composition). It is also great for curved seams.

Bias binding could easily warrant a post on its own. However, for the purpose of this I will simply focus on attaching a store brought double fold bias tape.

Method 1:
  1. Sew the seam with a seam allowance of at least 1cm.

  2. Cut bias tape slightly longer than seam.

  3. Press seams open or together towards one side.

  4. Align the edge of the bias tape with the wrong side of the seam allowance.

  5. Pin.

  6. Stitch in place along the fold of the bias tape.

  7. Fold the bias tape over so that it hugs the seam allowance.

  8. Press.

  9. Pin.

  10. Edge-stitch along the folded edge of the bias binding.

Method 2:
  1. Repeat steps 1-3 as above.

  2. Sandwich the seam allowance between the fold of the bias tape.

  3. Pin in place.

  4. Edge-stitch along the folded edge of the bias binding ensuring you catch the tape underneath.

Please get in touch or leave me a comment. I would love to know your thoughts on this tutorial. Are there any additional seam finishes you would like me to cover?

Thanks for reading!

Emma xx

This is a personal blog. Any views or opinions contained on this site are my own. I am not affiliated with any brands, products, or organisations mentioned, and do not receive any sponsorship, payment, or other compensation for any of the content on this site.

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