How to Sew a Flat-Felled Seam
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How to Sew a Flat-Felled Seam
A flat-felled seam is a sturdy, clean finish that encloses all raw edges on both sides of the fabric — you’ll recognize it from the side seams of jeans and workwear. It’s durable, neat, and gives garments a polished, professional look both inside and out.
Step-by-Step Guide
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A
Sew the first seam
Place the two fabric pieces wrong sides together and sew with a 2 cm (¾″) seam allowance. Sewing with the wrong sides together ensures both seam allowances sit on the outside, where they can be easily worked with.
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B
Trim one seam allowance
Trim one side of the seam allowance to about half its width using scissors or a rotary cutter. This reduces the bulk so that the folded seam lies flat against the fabric.
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C
Fold, press, and tuck under
Fold the untrimmed seam allowance in half toward the trimmed edge, press well with the iron, then fold again over the trimmed seam allowance to enclose it completely. Press firmly at each fold so everything stays crisp and in place.
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D
Pin and topstitch
Pin the folded edge so it doesn’t shift while sewing, then topstitch close along the folded edge. This final stitch secures the seam and gives a clean, finished look on both sides of the fabric.
Pro Tip
Press thoroughly at every step — a well-pressed flat-felled seam is much easier to topstitch precisely and lies completely flat against the garment. For an extra-professional look when topstitching, use a slightly longer stitch length, which gives the seam that classic workwear style.
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