A French seam is an option for finishing seams, generally used when sewing garments.
It is a good choice when sewing light weight, sheer or translucent fabrics, such as chiffons, when you can see the seams from the right side of the garment.
You sew this type of seam twice, thus making a very clean finish to the seam on the inside of the garment or your project. This method makes the seam very durable, since the double seams protect the raw edges inside layers of fabric.
French Seam Tutorial
Learn how to sew a French seam with this step-by-step sewing tutorial with photos showing you how to finish your seams with this technique. I've used bright colored fabrics with red thread so that it is easy for you to follow the steps.
Use the French seam technique for sheer fabrics, or when a seam might show while you are wearing the garment, like the inside of an unlined jacket. When you take your jacket off, it will look as nice on the inside as on the outside for a professional finish.
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Here is our step-by-step process:
Materials
- Pieces cut out for your garment
- Thread
Tools
- Sewing machine
- Iron
- Pressing surface
- Rotary cutter, mat and quilter's ruler OR fabric scissors, euler and marking pen
Instructions
- Cut out your pattern according to the pattern directions. Note the seam allowance with your pattern. This tutorial uses the measurements for a pattern with a 1/2-inch seam allowance, but will also provide for 5/8-inch seam allowance.
For the first seam, start by sewing the seam that you want the French seam finish with a 1/4-inch seam allowance, with the WRONG sides of the fabric together with the raw fabric edges lining up.
- Next step, trim this seam to 1/8-inch. I prefer to use a rotary cutter with ruler and mat. If your seam has a slight curve, a ruler won't work. Then I would use a small ruler to mark 1/8-inch and scissors to then trim the seam allowance.
- Press the seam allowance open. I like to press the seam open before I press it into a fold, as it gives a cleaner finished fold to your seam line.
- Then, with the RIGHT sides of the fabric together, press along the seam line creating a fold. Here is my pressed seam. I used two colors of fabric so it would be easier for you to see how this is a nice sharp pressed edge.
- Go to your sewing machine and sew 1/4-inch seam along the edge of the fold. If your pattern called for 5/8-inch seam allowance, sew a 3/8-inch seam. I used my quilters quarter inch presser foot.
- Press the seam flat on the inside. Here is the finished French seam on the inside. This gives a nice clean finish to the inside of your garment.
- And, the outside of the finished seam.
Notes
French seams are best for straight lines or very slightly curved lines, like side seams, back seams, under arm seams. It is not suitable for seams with strong curves like insetting a sleeve into a bodice.
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What are French seams?
Sewn twice, French seams enclose the raw edges inside the fabric.
Start by sewing with the fabrics WRONG sides together, trimming and then sewing the seam again with the RIGHT sides together.
This creates a seam finish that is very durable, and looks great! No raw edges are visible or subject to fraying!
Are French seams difficult?
No! This seam finish is perfect for beginners!
You need to sew the seam twice, but the finished seam is as beautiful on the inside as it is on the outside. Even beginner sewists can have great looking French seams!
What are French seams used for?
French seams are most effective on straight seams, like side seams, center back or underarm. Don’t use it on highly curved seams like insetting a sleeve.
The technique is popular with sheer fabrics, especially if you can see the seam line when wearing the garment. French seams are not suitable, however, for heavy weight fabrics like a thick wool.
Looking for a great finish for curved seams or heavy weight fabrics? Try the Hong Kong Finish!
What are the advantages of a French seam?
- The finished edges of your seams look as good on the inside as they do on the outside of your garment
- Your fabric is less likely to ravel and fray. This finish is perfect for light to medium weight and loosely woven fabrics, and linens (that ravel easily).
- Durable seam with the raw edges enclosed in the seam. Perfect for clothes with high wear.
What are the disadvantages of a French seam?
- The final seam doesn’t lay flat and can move to either side of the seam line. It does help to give it a good press, and make sure when you are attaching this seam to other pieces in the garment that you have both ends of the seam folding the same direction.
- This seam finish does not work well with curved seams, so use a different seam finish for those applications.
- Thick fabrics do not work well with a French seam because they become too bulky.
What is the finished width of a French seam?
The inside finished width is 1/4-inch. Start with a 1/2-inch or 5/8-inch seam allowance for the first pass. With the trimming and double seam, the final seam allowance is 1/4-inch.
What types of fabrics work best with a French seam?
The French seam is perfect for delicate fabrics and lightweight fabrics. If you have a medium-weight fabric, test this method of a seam finish on a scrap of the fabric you are using to see how it lies. You might be happier with a flat-felled seam. This method is not suitable for heavier fabrics, as there would be too much bulk.
Here is how Chardel used French seams when making a four-layer wedding gown for her daughter.
Three generations collaborated on my daughter’s 4-Layer Wedding Gown. She was the designer, we took my mother on a fabric shopping expedition in Portland, and I was the stitcher.
My daughter works in local theater, so she had access to Seattle Opera’s annual costume sale. She found some treasures! She scored big time with dresses that had China silk skirts (which became the lining) as well as a large piece of lightly flowered rayon yardage. The flowers look hand painted, and the rayon drapes beautifully.
She wanted a lace overlay, and we found one we liked very much, but it didn’t quite “watercolor” the floral enough. A layer of silk chiffon between the print and the lace gave the dress just the hint of color that the bride wanted.
We started with a tissue fitting a la Pati Palmer, and that was a great start! Muslin #1 was by no means the last, but it told us the style changes we wanted to make: raise the neckline slightly and add enough “swish factor” to the fullness of the skirt to make the dress more dance-able.
A second muslin incorporated the “swish”.
The dogs (one is under the skirt) approve the muslin. In the photo below, I am working up the courage to cut the “real” fabric.
The silk chiffon was a bear to work with because it had a mind of its own and tended to be cranky. I saw a tip on Pinterest that recommended laying chiffon on a sheet before cutting. The brilliant tip prevented the silk from slip-sliding on the cutting table! I used a little painter’s tape along the edges, too, to keep everything stable while pinning.
Starting the French seam wrong sides together on the main floral fabric.
Silk chiffon French seam. This stuff was much easier to sew than it was to cut!
The lace had a little give, so it was quite forgiving during stitching. It was a happy surprise.
Good omen: what was left on the thread spool at the end of a seam.
The 4 skirt layers are sewn and allowed to hang so the bias could find its natural resting place before marking the hem.
Time for heart palpitations. Invisible zipper, check. Thank you Bernina #35 foot. Making the 4 French seamed layers float freely below the zipper? That’s when I felt like I had won the lottery!
Here’s the front of the dress. Look at the shelves. Can you tell I’m a quilter?
Drum roll, please. The final hem!
The bride with her flower girls on the Big Day!
See our article on how to finish seams that highlights a flat felled seam, Hong Kong seam, finishing a seam with bias binding, a welt seam that is also known as a mock flat felled seam, and finishing a raw edge with a zig-zag stitch.
