When you’re working with lightweight, sheer fabrics, there’s a sense of airiness and elegance to them. Which means they deserve an equally-as-elegant finished seam that hides all your raw fabric edges. Enter the French seam .
This particular finish gets a bad rap for being tough to execute, but it’s easier than you might think. The big thing to remember is that instead of sewing your right sides together (which you do in nearly every sewing project), your first seam is sewn wrong sides together. Once you have that slightly-backward process down though, it’s smooth sailing!
Whether you’re sewing together a breezy blouse or finishing an unlined jacket, here’s how to perfectly sew a French seam.
How to Sew a French Seam
What You Need
1. Determine Your Seam Allowance
Look at your pattern to determine the seam allowances it calls for. Subtract 2/8" (aka ¼") from that number. (So if yours is ⅝”, your number is ⅜”) This will be the seam allowance for your first seam.
Good to Know
If you don't want to do math, you can also line the left side of your presser foot up with the seam allowance that your pattern calls for. (On most machines, this will be ¼”.)
2. Pin and Sew Your Seam
Pin your fabric wrong sides together (yes, do it!) and place under your presser foot at the ⅜" seam allowance (or whatever number you calculated in step 1). Sew the entire seam.
3. Trim Seam Allowance
Trim the seam allowance down to ⅛".
If you’re working with lightweight fabrics that easily shift (hi, chiffon), pin a point on the seam to an ironing board or another pin-able surface. Go directly through the seam line, leaving the pin sticking up like a tack. Pull the whole seam taut. This will make it easier to trim close to your stitches; the closer you get, the more delicate your finished seam will be.
4. Press the Seam
Open the seam with the right side facing up, so the seam allowance is on top. Set the iron to the correct heat for your fabric type. Press to one side .
Turn your fabric over and press on the wrong side so the seam lays completely flat.
5. Prepare to Sew the Second Stitch Line
Fold the fabric on the seam, right sides together. Press the seam flat again with the stitching on the edge of the fold.
6. Pin the Second Seam
Pin the layers together on the stitching line if needed. As you become more experienced, you may find that you no longer need to do this and can skip this step.
7. Sew Second Seam
Insert the seam under the presser foot. Sew until your project’s seam allowance equals the number you calculated in step 1. Example: If you sewed at ⅜” and the seam allowance is ⅝” , that means you should sew this step at 2/8” or ¼”.
Good to Know
As you sew, the seam allowance of the first seam will become enclosed within the fold/seam allowance of the second seam.
8. Press Again
On the wrong side of the fabric, press the entire French seam to one side.
Turn your fabric over and press one more time on the right side.
Photos by Marni Weaver