How to Sew Flat Felled Seams

You usually see flat-felled seams on jeans, totes, backpacks and tents because of their durability. There are several steps involved to secure and encase the seam, and some machines may not be able to handle the thickness of certain fabrics. Once you learn to sew the flat-felled seam on a straight seam, you can use the technique for sleeve placement and other curved seams.

Difficulty: Moderately Easy

Instructions

Things You'll Need:

• Sewing machine
• Heavy duty needle
• Straight pins
• Thread
• Iron

1. Join two pieces of fabric with the wrong sides together. Pin them in place and sew a 5/8-inch seam, or whatever seam allowance your pattern calls for. Remove the pins as you come to them and backstitch at the beginning and end of each seam.

2. Open the seam, press and trim one side of the seam allowance down to 1/4-inch. Don't trim on the other side. If your pattern calls for a smaller seam allowance, trim this down to 1/8 inch. The seam construction is the same despite the size of your seam allowance.

3. Lay the larger seam allowance to the side covering the smaller one and press into place. You're working from the right side of the fabric, which is the opposite way you normally sew a seam.

4. Wrap the wider seam allowance over the edge of the smaller one, until the edge almost meets the original seam line.

5. Continue folding and encasing the cut edge, laying the finished seam over and pinning it in place. If done correctly, you've encased the entire length with the folded edge wrapped neatly over the trimmed side of the seam.

6. Press the seam thoroughly. Use a pressing cloth if necessary.

7. Topstitch 1/8 inch from the edge of the fold, removing the pins as you come to them. Use your pressure foot as a guide to sew a straight stitch, keeping it an even distance from the original seam stitching line and continuing down the length of the seam.

Tips & Warnings

• Use a heavy-duty sewing machine needle when sewing a flat felled seam on heavy fabrics, such as denim, to prevent needle breakage or possible damage to your machine.
• Practice making a flat felled seam on a scrap piece of material until you've perfected the technique. If you don't get it exactly right, you can rip it out and try again without damaging your project.
• When pressing your seams open, use a setting that's appropriate for your fabric to prevent damage.