How to Understitch Facing

Understitching is a sewing must as a clean finishing method when a facing or lining is used when sewing a garment.  To get a professional finish on your garments, don't skip the understitch facing.

What is understitch facing?

Understitch facing is a line of stitching sewn close to the edge of a facing or lining to keep it from rolling toward the outside. It is sewn inside of the piece of clothing in order to keep the fabrics flat and aligned once the garment is finished.

Understitch sewing is especially useful when sewing necklines.  It keeps the facing or lining firmly on the inside of the garment without any stitches showing on the front.

Learn more about how to understitch facing by watching our video or keep reading this post.

What is the difference between topstitch and understitch?

Understitching is a useful and functional stitch to stop facings from rolling forward and peeking out at seams.  It is not meant to show on the right side of the fabric.

Topstitching, however, can be both a decorative and a functional stitch.

Topstitching is meant to show on the right side of the fabric and is often used to add a clean and decorative look.  It is functional when it is used, for example, to secure a pocket in place while also decoratively highlighting the style lines of the pocket with an outline. 

Do you need to understitch?

When there is an edge in sewing that has a facing or lining attached, understitching is necessary.

At the seam line where the raw edge of the garment is sewn to the facing or lining's edge, an understitch will need to be sewn in order to keep the seam stable and laying flat.

Understitching is used on:

• necklines
• armholes
• front openings
• waistbands
• pockets
• sleeve and pant cuffs
• skirt/dress slits and vents with lining

Understitching plays a vital role in sewing a clean, professional-looking garment.

WHAT YOU NEED to Understitch facing

• Fabric with a raw edge
• Facing or lining fabric
• Threaded sewing machine
• Scissors
• Iron
• Ironing board

INSTRUCTIONS for understitch sewing

STEP 1: stitch the two pieces of fabric together

Line up the edges of the fabric and the facing with the right sides together. Pin the fabrics together if necessary.

Take them to the sewing machine and run a line of stitches following the pattern's directions for the seam allowance.

The finished seam is shown below.

step 2: Press the seam allowance before understitch sewing

Once the fabrics are sewn together, take them to the ironing board.  Iron the seam allowance toward the facing.

Turn the piece of fabric over and iron the front side to make sure it is even and nicely pressed.

step 3: Understitch on the facing 

If the seam is curved, it will be necessary to clip the seam allowance along the curve. If it is a straight seam, no clipping is needed.

Take the pressed fabric to the sewing machine.  For this tutorial, a contrasting thread is used.  Actual understitch sewing would be done in matching thread.

With the right side up, sew a second line of stitching 1/8" to 1/4" away from the original seam on the facing fabric.

This stitch will sew the seam allowance to the facing fabric.  The finished seam is shown below.

step 4: Press the understitched fabric

Take the garment piece to the ironing board and make a final press.

With the right side of the fabric up, fold the facing under the fabric at the original seam line.

Iron on top of the garment fabric with the facing folded underneath.

Turn it over and give the garment fabric a final press. The facing will now be sewn and pressed to stay aligned.

The photo below shows the wrong side of the ironed and understitched facing.

other finishing techniques

Basic lapped seam

Double stitch seam finish

Turn and stitch seam

Pinked seam