How to Sew a Flat Felled Seam

A flat-felled seam is a type of encased seam every fashion sewer needs to know! Thanks to two parallel rows of stitching, this is a very strong seam that looks beautifully finished on both sides. Because of this strength and finish, you can find these seams everywhere! One of the main places you'll find them are in jeans along the inner side of both legs. You'll also find these in shirts (especially men's shirts), blouses, some outerwear, and in outdoor fabric products like tents. So let's find out one method of sewing them: 

As mentioned, this seam looks finished on both sides, so how this seam looks on your project will first be determined by which way you put your fabrics together. If you want to be able to see both lines of stitching as shown in the opening photo, you'll want to put the wrong sides of your fabric together. However, if you only want to see the seam (without any stitching) and a parallel line of stitching running beside it as shown in the last photo, you'll want to put the right sides of your fabric together. 

Step 1: After putting your fabrics together (pinning if necessary) in your chosen direction, sew a 5/8" (1.5 cm) seam allowance. Press along the whole seam! Pressing now will help set the stitching in place and make your seam stronger and easier to work with! 

Step 2: Trim one of the seam allowances to between 1/8" (3 mm) and 1/4" (6 mm), making sure not to cut or nick the other seam allowance. The side you trim will be the side you press the seam toward later and the side that will get the second row of stitching.

Step 3: Using an iron (with steam if necessary), press the seam open. If you're using a thicker fabric or one that's difficult to press, you may want to reverse this and the previous step. I just prefer this order because it seems easier to get a smooth, clean cut.

Step 4: Fold the larger, untrimmed seam allowance so it just meets the seam and press.

Step 5: Fold the seam allowance again over the seam so it covers the trimmed seam allowance and press.

Step 6:  Edgestitch 1/8" (3mm) on the fold. Give the entire seam a good, final steam press and you're done!

To get this look, put wrong sides together in the beginning. 

To get this look, put right sides together in the beginning.

Now like I mentioned in the beginning of this tutorial, this is only ONE method for sewing flat-felled seams - there are other methods. You can even get a special felling foot for your machine. But this method does not require any special feet or tools other than a sewing machine and a good iron.

The biggest tricks to getting a great looking flat-felled seam lies in the pressing and sewing well-formed, very straight stitches. If you take the time to press well in the places specified, you can easily get a beautiful seam that's going to leave people asking, "Where did you buy that!?"

Don't forget to like and share this tutorial and leave your comments in the comment section below!

Happy sewing,
Brian Hinson