Sewing Basics - Plain and French Seams

Joining fabric together with seams is a vital part of sewing (of course!) The finishing of your seams and the type of seam you use will make all the difference to your finished garment or sewing project.

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Seams are vital not just to the way your sewing looks but also the durability and quality of your finish.

Raw edges can look messy and be uncomfortable against skin, so learning how to sew seams is an important first step when it comes to dressmaking.

In this post we will take a look at the two most common types of seams that can be stitched on a home sewing machine.

As your sewing expertise progresses you will realise that there are lots and lots of different types of seams, however it's best to master the most common seam types first.

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Choosing which type of seam to use

Fabric Type

You need to carefully consider your fabric before deciding on a seam to use.  Look at the weave of the fabric, is it tight or loose?  Also you need to get an appreciation for what will happen to the raw edge of the fabric when you cut it, will it unravel, go all curly or roll up?

Use and Care of the Garment or Sewing Project

You need to think about the stresses and strains that will be placed on the seams and this largely depends on what you are working on.  Anything where the wearer will be moving a great deal needs a strong seam, also anything that will take weight such as a bag needs careful consideration.

Where is the seam?

Will it be visible, against the skin or is it hidden? Does the seam curve or is it straight?

All these factors above will determine which seam you choose to use. As you become a more experienced dressmaker you will soon be able to eye up a piece of fabric from 10 yards, knowing exactly how it will respond to cutting and which is the best seam to use.  You may even start thinking about investing in an overlocker to get a really professional finish to your dressmaking!  We'll post more on overlockers and how to serge seams soon.

Here are the two most common seams - The Plain seam and the French seam.

Plain Seam

Diagram of a Plain Seam

The plain seam is the most basic of all seams and as it is essentially one line of stitching it is very commonly used.  It also forms the basis for many seam types.

How to sew a plain seam: You simply place the fabric, right side together, and stitch a straight line with your sewing machine or by hand and leaving the desired seam allowance.  If the pattern or sewing tutorial does not state a seam allowance you should use the standard 5/8 of an inch.

For knitted fabrics, or fabrics with stretch you can use a zig zag stitch for more give.

This Plain seam (image from Oliver + S) has been finished with pinking shears - this stops the fabric from unravelling and looks pretty too - you could also stitch the seam allowance to ensure the fabric does not unravel - see over on the Oliver + S blog, ideas for professionally finishing a plain seam.

How you finish your seam allowance after sewing and pressing a plain seam can make a huge difference to the look and durability of your seam.  You should always press your seams neatly if nothing else!

Ways to finish a Plain Seam

• You can serge the seam allowance using an overlocker, either serging the seam allowances together or seperately so they lie flat.
• Neaten and protect the raw edges with zig zag stitching - this mimics the effect of an overlocker but doesn't look quite as professional.
• Folding them in and stitching to protect the raw edge (essentially hemming each side of the seam allowance) - looks great but can be fiddly on certain fabrics.
• Trimming them with pinking shears.  A really simple finish, but not as durable.
• Binding the seam allowances with bias tape.

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French Seam

Diagram of a French Seam

A French Seam neatly tidies away raw edges and creates a beautiful finish to the inside of your sewing projects.  If you don't have an overlocker (they're quite pricey!) then a French seam can be a good alternative to achieve a more professional finish with your dressmaking.  French seams are great for light fabrics - don't try to use a French seam on anything too heavy as the layers of fabric will be too thick and your seams will bulge and be difficult to stitch.

How to sew a French seam: Sew together the wrong sides of the fabric first.  You then trim the seam allowance and press the seam flat.  Next, place the right sides together with the plain seam you have stitched inside on the fold.  You then sew the fabric together with the desired seam allowance, leaving the raw edges neatly enclosed within the seam.  Finally, just press the seam to one side.

French seams are not tricky and they look very professional.  If sewing a french seam on a curve you may need to clip the enclosed seam allowance (take out little snips) to improve the finish.

If you're thinking "Whaaat? Fold the what where with which side of the fabric?" Fear not, take a look at this great French Seam tutorial from Make It Love It.  We hunted for great tutorials and found the images on this one are really crystal clear, it shows you exactly how to sew up a prefect French Seam step by step with a nice contrasting thread so it's easy to see!

Consider where the French seam is going to be on the garment or sewing project, for example on a tightly fitting skirt a pressed plain seam may lie flatter and therefore be a better choice.

More Seams

There are many more seams and variations of seam types depending on the finish of raw edges. Find our quick guide here.

Beginner's Guide to Sewing

This pattern is part of our Learn to Sew series! Join us with a new tutorial each week to build your sewing skills and discover the magic of making your own clothes.

Find the full series here