A flat seam, particularly the flat felled seam, is a durable and neat method of joining two pieces of fabric where the raw edges are fully enclosed, resulting in a smooth, flat finish on both sides. It's commonly used in garments like jeans, shirts, and workwear where strength and a tidy appearance are important.
Here's how to sew a flat felled seam:
Understanding the Flat Felled Seam
Unlike a standard seam sewn with right sides together and pressed open, a flat felled seam is often started with wrong sides together. The process involves folding the seam allowances and stitching them down flat against the fabric.
This method creates robust folds that encapsulate the raw edges, preventing fraying. As highlighted in sewing tutorials, achieving a perfectly consistent fold can sometimes lead to one side of the seam appearing potentially less strong or neat during the intermediate steps or if not fully secured, compared to the finished, securely stitched seam. In manufacturing, specialized attachments on machines are used to feed the fabric edges into the correct position, ensuring consistent folding and efficiency.
Step-by-Step Guide to Sewing a Flat Felled Seam
Follow these steps to create a professional flat felled seam:
- Prepare Fabric: Place the two fabric pieces with wrong sides together.
- Sew Initial Seam: Sew a straight seam using your desired seam allowance (e.g., 5/8 inch or 1.5 cm).
- Trim One Seam Allowance: On one side of the seam, carefully trim the seam allowance down by about half (e.g., to 1/4 inch or 0.75 cm). It's important to trim only one side.
- Fold the Wider Seam Allowance: Take the wider seam allowance (the untrimmed one) and fold its raw edge inwards towards the seam line, enclosing the trimmed seam allowance. Press this fold neatly.
- Fold Seam Down: Fold the entire seam allowance (which now has the raw edge enclosed by the wider allowance) flat against the main fabric piece. The seam will lie to one side. Press this fold firmly.
- Stitch the Folded Edge: Stitch close to the folded edge, securing the seam allowance flat against the fabric. Aim for an even distance from the fold along the entire seam. This stitch is visible on the right side of the fabric and is a characteristic feature of the flat felled seam.
- (Optional) Second Stitch Line: For extra strength or a classic look (like on jeans), you can sew a second line of stitching parallel to the first one, further away from the fold.
Why Use a Flat Felled Seam?
- Durability: It's one of the strongest seam types, perfect for garments under stress.
- Neat Finish: All raw edges are enclosed, preventing fraying on both the inside and outside.
- Comfort: The seam lies flat against the body, reducing bulk and potential irritation.
- Appearance: Creates a clean, professional look.
When to Use It
- Jeans and denim garments
- Shirts and blouses (especially yokes and side seams)
- Pajamas and loungewear
- Workwear and outdoor gear
- Items where a reversible finish is desired
By following these steps, you can create a robust and attractive flat felled seam, ensuring your projects are both durable and professionally finished.
