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There are a number of different types of seams that have been developed over the years to do different jobs. While many have largely been superseded by the development of machine stitches that finish as you sew them, and by the development of the overlocker (or ‘serger’ in some parts of the world), it is useful to know some of the basic seams types and finishes. A lack of expensive machinery need not prevent you sewing the garments you want. Also, some of the older methods have never been bettered. Here I am concentrating on machine sewn seams using a standard straight stitch machine.

When you have chosen your fabric and pattern, you need to think about the most suitable way to sew the garment together. This will depend partly on the type of fabric, partly on the use the garment will get, and partly on the finish you want.

There are a few terms that you will need to know so that you can understand what the different parts of the seam are:

  • CUTTING LINE: the line on which the garment is cut out
  • STITCHING LINE/SEAM LINE: the line on which the seam is sewn
  • SEAM ALLOWANCE: the area of fabric between the stitching line and the cutting line. This is usually 5/8″ or 1.5cm. Some patterns allow more in some areas, and some allow less. Always check before making up a pattern.

Kate’s magic tip: a standard dressmaker’s tape measure is the standard seam allowance wide. Use it as a handy reference.

The following diagrams show some of the basic seams, and explain where they might be used.

Flat Seam

To sew this seam, place the fabric right sides together, and sew 5/8″/1.5cm from the cut edge, using a straight stitch. Press the seam allowance open.

This is the basic seam used as a basis for many of the others, and still the best option for a wide range of garments and fabric types. It is very good on fabrics that are fine but do not fray. It is also the standard seam for sewing any garment that is to be lined. For some seam finishes to use with the flat seam, look at the Seam Finishes page on my website.

French Seam

To sew this seam, start with the fabric wrong sides together. Sew the seam very close to the edge; about ¼”/ 4mm from the cut edge. Trim off any thready or uneven bits, and press closed. Turn the fabric right sides together and press again. Sew the seam again, this time about 3/8″/5mm from the edge, enclosing the cut edge, again using a straight stitch. Press to one side. This seam is useful on light fabrics, which can fray. It is also useful on semi-sheer fabrics. It can be used on blouses and shirts, and on some underwear.

Felled Seam

To sew this seam, place the fabric right sides together. Sew 5/8″/1.5cm from the cut edge. Press open, and trim one seam allowance to 1/3 of its original width. Press the full seam allowance in half, folding the cut edge towards the stitching. Fold over the narrower seam allowance, hiding the cut edges. Sew 1/8″/2mm from the fold. This seam is usually sewn with the fold towards the back of the garment.

For decorative seams, sew in exactly the same way but starting with the fabric wrong sides together. You can do the final line of stitching in a decorative thread. On very thick fabric you may need to cut a wider seam allowance: do a test seam first, before cutting out the garment.

This is a very strong seam, frequently used up the sides of jeans and trousers. It can also be used for its decorative effects on coats and jackets. On light fabrics, it gives a neat, flat finish and in the past was popular for making shirts, nightwear, underwear, and children’s clothes. Because all edges are enclosed, and it is very strong, it will withstand the frequent washing these clothes need.

All these seams can be sewn on a basic sewing machine.

© 2010 Kate Dicey & Bamber Sewing Machines