When you’re following pattern instructions, you may encounter a step that says, “Understitch the facing.” Here’s why this process is important and how to do it effectively.

Facings finish many garment edges at necklines, armholes, waistlines, and other openings. A properly installed facing doesn’t show on the garment’s exterior. To ensure the facing stays inside the garment, understitch it.

Threads’ seamstress Norma Bucko demonstrates her favorite method for understitching along a curved edge, such as a neckline. Her technique focuses on keeping the fabric layers—the garment, facing, and both seam allowances—in a particular configuration as you sew, to secure the desired edge shape.

Prepare the allowances

After joining the facing to the garment, trim the seam allowances to a scant 1/4 inch. You can trim both to the same width. Then clip them every 1/2 inch or so, all the way to, but not through, the seamline. Stagger the clips on the facing allowance and garment allowance. Don’t press the seam just yet.

Understitch the facing

Place the facing portion right side up under the presser foot, keeping the work flat. The facing should extend to the right of the presser foot, and the garment to the left. Be sure the seam allowances are beneath the facing, not the garment.

Straight-stitch 1/8 inch from the seamline on the facing. The key is to keep the facing flat at all times, even if the garment bunches up at the left. This allows the clipped seam allowances to spread as needed to create the curved shape. Avoid stretching or distorting the seam shape as you stitch. This stitching secures the clipped allowances in the desired curved shape.

When the seam is pressed, the facing rolls easily and completely to the wrong side  and holds its shape.

Insiders can…