Seam Finishes: French Seams

Simone Rocha, AW11, London.

When sheer fabrics are used the seam finish needs to be carefully considered since it can be seen from the outside of the garment. One of the most common ways of finishing seams for sheer and very fine fabrics is by using french seams.

French seams are basically like sewing a normal seam twice, and the seam allowance ends up encased inside a fold.

The steps below outline the instructions for sewing a French Seam:

Take two pieces of fabric where the seam allowance has been marked with a very small cut into the edge of the fabric.
Place the two pieces of fabric with wrong sides together and so that the edges and small seam allowance notches match up. It is important to note that where you would sew the fabric with wrong sides together for a normal seam – you must sew the seam with wrong sides together for a french seam.
Sew the pieces together from the notch and parallel to the edge of the fabric. The distance of your stitch from the edge of the fabric will depend on the seam allowance that you have allowed. Typically I have seen french seams done allowing for 1.2cm of seam allowance, in this case you will first sew about 5-6mm from the edge.
Then you will unfold both pieces of the fabric.
When you place the fabric flat you will have the right side up and the seam allowance facing out towards the right side of the fabric.
It may be necessary to trim down a little of the seam allowance and especially to trim away any frayed edges. This step will make more sense once you have sewn this type of seam before and you will get a feel for what needs to be trimmed.
Then fold both pieces of fabric back around the seam allowance.
Then you will have the seam allowance folded between the two sides. For most fabrics you may find it easiest to press the seam at this stage to help with the next step.
Then sew another line of stitching parallel to the edge through both layers of fabric and to one side of the seam allowance, encasing the seam allowance between the two layers.
When finished it should look like a normal seam from the outside and a folded seam on the inside. There should be no seam allowance or fraying showing through the seam on the outside of the garment.

Although it is hard to tell for sure whether or not french seams were used on the images below from Simone Rocha, they would typically be used on such fine mesh fabrics and fabrics such as silks, organzas, chiffons and other fine fabrics which fray easily.