Flat seam: Step By Step Tutorial

Flat seam

Flat seam, also known as jeans or loaded, is one of the most used and effective in clothing. It is resistant, polished and with many applications, ready to enter through the big door in the technical display.

If you are wearing jeans, with a quick look at the inner seam of the legs you will have the photograph of this seam live and direct. It is the ideal seam for much-used garments with areas exposed to the stress of the movement of our little bodies.

In today’s post we are going to see the steps necessary to make a flat seam in two versions:

  • The traditional and reversible.
  • The fast and non-reversible.

As you will see, there is something for all tastes and occasions!

Traditional flat seam

STEP 1 sew

  • Face the two fabrics on the right and secure with pins.
  • Sew with a straight stitch 1 – 1.5 cm from the edge.

The decision of the distance to sew from the edge is completely personal. Depending on whether it is larger or smaller, the result will be a flat seam more or less.

Each type of fabric, depending on its thickness and the garment to which it is applied, needs a different width of the flat seam.

As always, before starting to sew on the final garment, it is important to do some tests on small scraps.

Sew a straight stitch 1 cm from the edge of the fabric

STEP 2 cut the margin

  • Cut one of the seam allowances in half.

It is important to choose decisively the margin that we are going to cut since it will determine the side towards which the seam will “load”.

For this reason, it is very useful to have a sample of seams to remember, when we are sewing a garment, the mechanism of the seam.

Cut one of the two seam allowances in half

This will leave our seam allowance cut next to the one we have left untouched.

One of the seam allowances cut in half

STEP 3 Prepare with the iron

  • Iron the seam flat to set the stitching.
  • Open the seam and iron the seam allowances to the side of the widest allowance (not cut).
Iron seam allowances to one side
  • Wrap the edge of the narrowest margin with the widest margin.
Cover the narrowest seam allowance with the widest
  • Iron the fold to fix it.
Iron the folded seam allowance aside

STEP 4 sewing

  • For the reverse of the work, sew with a straight stitch to the edge of the fold.

When we master the technique, we can also sew it on the right side of the fabric to avoid changing thread colors on the machine. But, even with years of experience, we run the risk of leaving some part without sewing well.

Sew with straight stitching flat seam

This is the final look of our traditional polished reversible flat seam. On the right side, it has only one visible stitching, but on the reverse side, it has two.

Sometimes we can see two stitches on the right and this is because a second seam has been made so that it has double security, and incidentally it is more decorative.

Flat or Texan stitching

Flat seam quick version

This version is very useful in making shirts for boyfriends and husbands since it saves us significant time and the final effect is the same.

Once we have sewn the two sheets of fabric with straight stitching, the next step is:

  • Overcast the seam allowances together.

At this point, we are free to choose the finish that suits us best: zigzag, overlock finish, zigzag scissors …

Overcast seam allowances together
  • Iron the seam flat to set the stitching.
  • Push the seam allowances to the side we want to “load” the seam and iron.
Iron overcast seam allowances aside
  • Sew with a straight stitch on the right side of the fabric along the edge of the seam allowance.

If we are not sure, we can do it perfectly on the reverse, although the seams made on the right are always visually cleaner and more perfect.

Sew flat seam in its quick version

In this case, the quick flatlock seam has a topstitch on the right and two topstitches and the overcasting line on the reverse.

There are projects that require it!

Flat or Texan sewing quick version

Practicing relaxed and calm sewing is not incompatible with choosing, on the necessary occasions, versions of lighter or faster techniques.

I encourage you to storm the wardrobe and look for types of seams, little by little we are seeing them all!

If you see a new one or one that catches your attention, we hope to hear it!

Say goodbye,


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