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What Is a Seam?
A seam is a method of binding two or more pieces of fabric together, usually using thread to form stitches. However, glue and other forms of adhesive can also be used. Seams can be stitched by hand or sewn by machine.
Seams can either be open or closed.
- An open seam is one where the seam allowance, the piece of fabric between the edge of the material and the stitches, is visible.
- A closed seam incorporates the seam allowance within the seam finish, making it invisible.
How Are Seams Used in Garments?
Seams are an essential element to every garment and fabric accessory, as they join the material together to create the item.
- Seams are used for hems and to finish necklines and edges.
- Seams add shape through elements like darts, which are used to shape hips, waists, and bustlines.
- Seams are used to gather fabric and create pleats. Learn more about pleats in our comprehensive guide to pleat types here.
- Different types of seams can be used to create a different look for a garment and to finish and hide the fabric edges for aesthetic and practical purposes.
What Type of Seam Should You Use?
The type of seam you choose depends on the type of fabric you’re using and the final look of an item that you want to achieve.
- Some seams, such as French seams, are better for lighter weight fabrics.
- Bulkier enclosed seams, like the flat felled seam, are better for tougher fabrics like denim.
- Be sure to pick the right stitch length as well—the longer a stitch, the more likely the material is to pucker, which stitches that are too short can create undesired plaits.
7 Different Types of Seams
There are several different types of seams, each with its own characteristics.
- Plain seam. A plain seam is the simplest type of seam and can be used on almost any item. A plain seam is defined as any seam that attaches two pieces of fabric together with the wrong sides facing. The wrong side is the side of the fabric that doesn’t face outward when the garment or item is completed. The stitch length or type of stitch doesn’t matter, as long as it is one stitch line and it attaches two pieces of fabric.
- Double-stitched seam. This type of seam is just like a plain seam except there are two lines of stitching attaching the fabric for extra strength.
- French seam. A French seam should only be used on delicate, lightweight fabric, like chiffon or organza, as the seam uses a lot of material and can get bulky with heavier fabrics. Since the edges of the fabric do not show with this technique, a French seam is also great for garments where you want to hide the seams, like an unlined jacket.
- Bound seam. A bound seam looks like a French seam on the right side of the fabric. There are no visible stitches on the right side of the fabric, and on the opposite side, the fabric edges are neatly enclosed.
- Flat-felled seam. A flat-felled seam is an extremely strong closed seam that is often used for items like jeans. It covers the fabric’s raw edges well and keeps the seam flat. Like the french seam, it is a double-stitched, closed seam.
- Welt seam. A welt seam is also frequently used for jeans, as it is very strong, but it is less bulky than the flat-felled seam because it is not enclosed and the raw edge of the fabric is visible.
- Lapped seam. A lapped seam is typically used with fabrics that don’t fray, such as leather and fleece. For a lapped seam, the right side of the fabric faces up and the pieces overlap, instead of right or wrong sides together.
4 Seam Finishing Techniques
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In open seams, where the seam allowance is exposed, the raw edges need to be finished to prevent fraying. Here are ways to finish your open seams.
- Pinking shears. Pinking shears are serrated scissors that create a zigzag edge. Trimming a seam allowance with pinking shears can prevent fraying.
- Bias tape. Bias tape is a narrow strip of fabric that can be folded over an exposed seam to secure and hide the edges. This is often used for unlined garments and bags, and for the edge of quilts.
- Serger. A serger is a special type of sewing machine that cuts the raw edges of the seam and creates overlocked stitches around the edge as it is sewn. This is a very professional way to finish a seam, and serged seams are found on most store-bought clothing.
- Zigzag stitch. Zigzag stitching along the raw edge of the seam will secure the edges and prevent fraying.
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