You got your pattern and it does not include seam allowance? What to do next? How to add seam allowance to a pattern? What tools to use when adding seam allowance?
If you already know what a seam allowance is and have chosen the one you want to add to your pattern - you came to the right place! Here are the tips, tricks and tools to make this task easier!
How to add seam allowance to a pattern?
A lot of the commercial sewing patterns sold these days have a seam allowance included. However, buying a sewing pattern without seam allowance added can be a great decision. You can decide the size of the seam allowance you want to add overall. You can also choose to add more hem allowance and or less around the curved edge of the armhole. Or maybe you just want a consistent seam allowance all over your garment panels.
Adding seam allowance is actually pretty easy. However, a lot of people don’t like doing this task because it requires a fair amount of precision and takes a little bit of time.
All you need to do is:
Place the pattern pieces on the paper or fabric with enough space between them.
Take your tailors chalk or pencil and a ruler (or your preferred guiding tool).
Trace (or make dots and later connect them) all around the pattern piece while measuring the distance.
There are also a couple of tricks to use when adding a seam allowance to shoulder seams, side seams, sleeve inseams and sleeve hems.
Adding seam allowance to shoulder seams, side seams, sleeve inseams and sleeve hems
To get a professional seam finish you might want to add a seam allowance for some sewing pattern parts using slightly different technique than the others. These parts include shoulder seams, side seams, sleeve inseams and sleeve hems. These are the techniques when adding seam allowance to these parts:
Adding seam allowance to shoulders seams
Draw a line parallel to a shoulder seam. Fold the paper that you're drawing on along the edge of the shoulder stitching line. Take the tracing wheel or awl. Using a tracing wheel mark a few cm on the top of the neckline edge and armhole edge. Unfold the paper and you will see the change direction of seam allowance for the corners.
Adding seam allowance to side seams
Draw a line parallel to a side seam. Fold the paper that you're drawing on along the edge of the side seam stitching line. Take the tracing wheel or awl. Using a tracing wheel mark a few cm on the bottom of the armhole edge and the side of the hem edge. Unfold the paper and you will see the change direction of seam allowance for the corners.
Adding seam allowance to sleeve hems
Draw a line parallel to a sleeve hem. Fold the paper that you're drawing on along the edge of the sleeve hem stitching line. Take the tracing wheel or awl. Using a tracing wheel mark a few cm on the bottom of the sleeve inseam edges. Unfold the paper and you will see the change direction of seam allowance for the corners.
Adding seam allowance to sleeve inseams
Draw a line parallel to a levee inseam. Fold the paper that you're drawing on along the edge of the sleeve inseam stitching line. Take the tracing wheel or awl. Using a tracing wheel mark a few cm on the bottom of the armhole edge. Repeat with another side. Unfold the paper and you will see the change direction of seam allowance for the corners.
This technique also can be used for other types of seams when you are unsure how to finish the corners. It helps the seam allowance to match the shaping of the garment part when it is sewn and turned right side out.
Important things to know when adding a seam allowance
Cut on fold
Do not add the seam allowance to the edge of the sewing pattern that needs to be cut on the fold.
Which seam allowance to add
Make sure you know which seam allowance to add where and take into account a material you work with. For example, curved seam requires smaller seam allowance than edges that are straight lines. And knit fabrics require smaller seam allowance then woven fabrics, because the raw edges knits do not fray so easily. Also if you are working with certain types of seams, like french seam or flat felled seam, or even a quilt seams - you might want to learn what is a standard seam allowance for these types of seams. And don’t forget one garment can have different seam allowances on different parts of it.
Adding seam allowance to curved edges and working with thick fabrics
You also might want to trim the seam allowance you have added if you are working with thick fabrics or curved panels. This step prevents a garment from having undesired bulky seams. Smaller seam allowances sometimes are needed for professional outcome.
What tools to use when adding seam allowance?
Because keeping accurate distance from the seam line / stitching line is quite tricky - people came up with all kinds of tools and tricks to make this task easier and more accurate. From a simple tape measure and tools used in pattern drafting, to DIY tools that help to add a consistent seam allowance - there are plenty of sewing tutorials and choices to make this precise task easier.
Here is the list of tools that are used when adding seam allowance:
A seam gauge or a sewing gauge is a short ruler with a slider. It is a similar tool to a caliper. Just like tape measures it usually has markings in inches and centimeters. This tool can be a useful guide when adding a seam allowance - you can mark points at a correct distance accurately and consistently. It is also handy when altering hems, measuring intervals between pleats, or even a button when you need to know the size of a buttonhole.
Pattern making ruler also called pattern master or pattern maker
Pattern drafting rulers come in multiple types and shapes. You can find a curved ruler, a French curve, transparent ruler and a ruler shaped like the letter L. You can have multiple of these rulers and find all of them useful not only in pattern making but also in everyday sewing. These rulers are extra help when adding seam allowance to tricky places on a pattern block like armhole, neckline, princess seam or a curved hem.
Double tracing wheel (adjustable)
This is a tool with two parallel spiked wheels that are attached to a handle. When tracing the pattern it leaves small marks on the layer beneath it. These are useful when you need to transfer seam allowance together with the stitching line. You can even use this tool directly on some fabrics without tracing paper. It is a great tool serving two purposes - helping you with seam allowance as well as straight seams.
DIY guide (strip of card paper or circle with a small hole in the middle)
This is the cheapest and most simple way to create your own seam allowance guide. Just take a strip of card paper the size of your preferred seam allowance and use it as a guide to keep the same distance around your pattern piece. Another way is to cut out a small circle that has a radius of your preferred seam allowance, make a small hole in the middle of it and use pencil to draw though that hole, while using the edge of the circle as a guide to go around the pattern piece. You can have a larger seam allowance by making a circle’s radius bigger and smaller seam allowance by making it smaller.
Pencils taped together
This is the second easiest and cheapest solution. Just tape two pencils together and you will be able to trace your pattern while adding a seam allowance at the same time. However, this method does not allow you to choose the exact distance from the edge of your pattern. Therefore, the size of your seam allowance will be random. This solution also works with two fabric markers taped together and drawing directly on the fabric, transferring stitch line and seam allowance at the same time.