How to Sew a Flat Felled Seam

A flat felled seam or run and fell seam is a sturdy seam used for apparel. Most notably in jeans and workout apparel.

To sew a flat felled seam, sew your fabric with wrong sides together and a seam allowance that is double the width of the finished seam.

Pin with wrong sides together

Sew

Cut one end of the seam allowance down to ¼ inch.

Cut

Press the seam to the side with the cut seam allowance.

Press

Fold the intact seam allowance in half so the raw edge is folded under and pin.

Fold the seam over

Press again.

Sew the folded seam down 1/8 of an inch from the fold.

Sew

And now your flat felled seam is complete.