felled seam
A seam made by placing one edge inside a folded edge of fabric, then stitching the fold down. The fold encases the raw edges, which protects them from fraying, and may be secured with a topstitch or a whipstitch.
felled seam: raw edges buried inside a fold, then stitched
A felled seam is a seam construction in which one fabric edge is folded over and wrapped around the other edge, then stitched in place. The result is a seam with no visible raw edges on either side of the garment. This is achieved by laying one seam allowance flat against the garment body, folding the opposite seam allowance over it, and then stitching through all layers to secure the fold. The final appearance is a visible line of stitching on one face of the fabric, with a clean fold on the reverse.
Felled seams are common in workwear, sailcloth, and denim because they resist fraying and tolerate repeated washing and mechanical stress. The construction typically uses seam allowances between 3/8 and 5/8 inch wide. First, the two fabric pieces are sewn together with a regular seam, then one allowance is trimmed to half width. The untrimmed allowance is folded to encase the trimmed edge, pressed flat, and then stitched again, usually 1/8 to 3/16 inch from the fold. Some mills use a single operation felling machine that folds and stitches in one pass, while others perform the work in two distinct stages.
Variants and applications
The double felled seam, used in jeans and heavy cotton goods, involves folding the seam allowance twice: once to encase the raw edges, then again to create a neat packet on the inside of the garment. Single felled seams are faster and used where only one face needs protection, such as on the inside of waistbands or linings. Flat felled seams, common in shirt construction, create a symmetrical appearance where the fold is visible from both sides and the garment body lies very flat. The technique is also sometimes called a run and fell or fell seam.
Tension and thread choice matter significantly. The stitching that secures the fold must be tight enough to prevent the fold from lifting or rolling during wear or washing, but not so tight that it causes puckering. Lightweight fabrics may use 60-weight or 70-weight thread, while heavy denims use 40-weight or heavier. If the fold is stitched too far from the edge, wrinkles can form underneath. If stitched too close, the thread may cut into the fabric edge and cause the seam to fail.
The name felled comes from the past tense of fell, an old textile term meaning to fold or overlay. In traditional tailoring, felling by hand was precision work, and the seam remains a marker of quality construction. Modern felling machines can produce 3,000 to 5,000 seams per hour, but they still require careful fabric feeding and tension adjustment. Felled seams add cost and time compared to simple flat-fell or serged seams, so they are specified only where durability and appearance justify the investment.