Types of Seams

A seam is a line where two pieces of fabric are joined by application of a series of stitches or stitch types with a defined geometry to one or several thicknesses of fabric material.

1. Seam dimensions

Seams have three dimensions: length, width, depth. Seam dimensions affect garment quality, performance, and cost.

• Seam length: is the total distance covered by a continuous series of stitches, such as side seam or shoulder seam.
• Seam width/ seam allowance: is measured from the cut edge of fabric to the main line of the stitches
• Seam depth: is the thickness or compressibility of a seam, both of which are major factors in appearance and comport of a garment. Seam depth is affected by fabric weight, fabrication, and selection of seam type.

2. Types of Seams 
According to American Society for Testing and Materials (ASTM) types of seams are;

1. Superimposed Seam
2. Lapped Seam
3. Bound Seam
4. Flat Seam
5. Edge Finishing
6. Ornamental Stitching

1) Superimposed seam
This is formed by joining two or more pieces of fabric, usually with seam allowance edges even and one piece superimposed over the second.


2) Lapped seam
This is formed by two or more pieces of fabric joined by overlapping at the needle. Fabric piece extend both left and right from the overlap area.


3) Bound seam
This seam requires a separate piece of fabric that encompasses the edge of one or more pieces of the garments. These seams are used to finish plain necklines of T-shirts and so on.

4) Flat seam
A flat seam is formed by having two pieces of fabric meet exactly (not overlapping) at their edges. A cover stitch is used to sew the two pieces of fabric together. They are commonly used for seams of sweatshirt, lingerie, and long underwear.


5) Edge finishing
This is the stitching that covers a cut edge or provides a finish for a single ply of fabric with a folded-edge configuration. This seam is used to prevent the edges of the fabric from rolling or curling.


6) Ornamental stitching
This is decorative stitching may be used on a single ply for decorative purpose. It can be done anywhere on a garment except the edge.