There are many different types of seams that you can use to complete your projects. You'll find several listed below with an illustration of the seam construction, a detailed explanation and also a cross section, where appropriate.

The cross section is very important because it shows you the depth of the completed seam. You should use different seam treatments according to the final appearance you desire. The overall depth of the seam will tell you if the seam is going to be bulky or not. There are many places on garments where you want to keep the seam as flat as possible. Use these depth illustrations to get an idea of how the finished seam will look.

The measurements given for different seam allowances and trimming are as suggestions only. Feel free to change these as your project dictates.

You should try all of these seams with some scrap fabric to get a good feel for their construction and application. 

Standard Plain Seam

Place the right sides of the fabric together. Sew a straight stitch along the seam line. You can press the seam open or to one side. Notice how much bulkier the seam becomes when it is pressed to the side?

French Seam

This is suitable for lingerie, blouses and sheer garments. With the wrong sides together, sew a standard seam with a 1/2”  / 12mm seam allowance (#1). Trim the edge to 1/8”  / 3mm from stitching. Press the seam open. Then fold with right sides together, stitch a new seam encasing the seam allowances (#2). Press all to one side. This is a bit of a bulky seam, but it should only be used on lightweight fabric. It is all enclosed and provides a nice finish.

Flat Felled Seam

This is used where a flat finish is needed, such as shirts and shorts. This is a tough seam, very commonly found on jeans and other heavy fabrics. Create the seam with wrong sides together (#1). Trim one edge close to stitching line and press long side over trimmed side. Turn under the other raw edge about 1/8” / 3mm. Lay this edge over the other, press and stitch close to the edge fold (#2).

Felled Hem Seam / French Fell Seam

This is created the same way as the Flat Fell Seam above. However, the final stitching (#2) is done by hand with a small stitch.

Lapped or Tuck Seam

Use this to join two pieces of the garment with the stitching on the outside. The seam allowance is caught in the seam. Turn one edge over on the seam allowance, press and baste. Place this piece over the other seam edge to the stitching line. Stitch on the right side. The seam is lapped if the stitching line is close to the fold. The seam is tucked, if the stitching line is farther away from the fold intentionally for a more tailored finish.

Edge Stitched Seam

This seam creates two rows of top stitching, one to either side of the seam line. With right sides together, stitch on the seam line. Press the seam open and then stitch again to either side of the seam catching the seam allowance in the back.
Welt Seam

This seam has different seam allowances on each piece, one is 1/4”  / 6mm and the other is 1/2”  / 12mm. You’ll want to finish the longer seam edge first (overlock stitch is best). With right sides together, stitch on seam line (#1). Press the seam to the side so the longer, finished edge goes over the shorter one. Turn to the right side and topstitch catching the longer seam allowance on the back (#2).

Slot Seam

This seam is used primarily for decoration. You can put another color or type of material in the slot. Fold the seam edges under forming “tucks” and baste. Optionally, you can stitch each one, instead of just basting. Lay another strip of fabric under the two pieces with the edges meeting the seam allowances of each piece. Stitch on the right side as far from the folded edges as you like. The farther away the stitching is, the larger the “tucks” will be.

Piped or Corded Seam

This is a decorative seam often found in upholstery work on cushions and seat covers. The piping fabric should be cut on the bias, if it will be used on a curved area. Otherwise, you can cut it on the straight grain. Fold the strips in half, wrong sides together, encasing a cord. Use a zipper foot and sew a seam very close to the cord. Sandwich the piping between the right sides of the fabric with seam allowances even. Use the same zipper foot to sew together. Piping does not have to contain a cord. You can also sew piping to only one edge of the fabric, such as a neckline.

Fagoted Seam

For those of you in the US this word may seem offensive. The origin of the word fagot referred to a bundle of sticks. It was used to describe this stitch most likely because the threads are “bundled” during construction. It has nothing to do with the slang usage today.

This seam is used for decoration and can provide a beautiful detail to your project. Draw parallel lines on a piece of paper to indicate the width of the fagoting. Turn under the raw edge of each piece half the width of the fagoting. For example, if you want your width between to be 1” / 25mm, turn in each edge 1/2” / 12mm.

Baste these folded-in edges to the paper on the lines you’ve drawn. Fagot stitch the two edges together and then remove the paper. To get your stitches even, you may choose to make equal marks on the paper to indicate where to stitch.

Bar or Ladder Fagoting

Use embroidery thread or buttonhole twist. Bring needle out on one edge, take a stitch directly opposite on the other edge. Wind needle around thread three or four times and bring back to starting point. Slide the needle through the fold for the next stitch.

Crisscross Fagoting

Work from left to right bringing the needle from underneath on the lower edge. Work diagonally and take a stitch under the upper fold. As you work the stitch back and forth, the needle passes each time under the thread of the preceding stitch.

Self Fagoting

Use edge stitched tubing (same or contrasting fabric) or narrow grosgrain ribbon. Cut the tubing or ribbon in pieces longer than the width of the fagoting. Lay them out under the folded edges in even spacing and baste or pin. Sew down close to the fold on each edge of fabric.