How to prewash fabric. When you definitely need to do it and when you don’t.

Do you know the consequences of not knowing how to prewash fabric before sewing your garments? 

Two words. Total disaster. 

Not a lot of people know this. 

But most fabrics should be always pre-washed or you can end up with a lot of misfortunes with your finished sewing project.

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Here is one example. 

Have you ever bought a piece of garment that fitted you perfectly in the store? But then… 

You washed it and try it on again and now is like 2 sizes smaller?

Well, this has happened to me more than I would like to recognize. 

One time it even happened that I bought a linen beautiful dress with a polyester lining. 

After only one use I washed it and, do you know what happened?

The outside of the dress shrank by a lot, while the lining stayed intact. 

Needless to say, I never used that pretty dress again.

But why did this happen? 

Well… 

Usually big cheap factories, greedy as they are, skip the pre-washing of their fabrics when they make their clothes. 

In my experience with the fast fashion industry, this happens for two reasons. 

The first one being that if they were to properly wash their fabrics before sewing, they will lose a considerable huge amount of fabric due to their shrinking. 

And the second reason is, of course, to save up one step of the supply chain and save lots of cents.

But here is the thing my dear friend. We are nothing like those factories. 

We actually care and put love to everything we sew. 

That is why this topic is so important for you to learn.

Because we don’t want any of our carefully sewn projects going to waste just because we skip such an important step. 

So, do you want to learn everything there is to know about how to prewash your fabrics? 

Let’s dive in!

Don’t forget to read this too: Basting Stitch. What it is and when to use it.

How to prewash fabric. 

Although not all fabrics need to be washed before sewing, if you are unsure, just wash it first. 

As a basic rule, you should always prewash your fabrics with the same process you would wash the final garment or sewing project you are going to use them for. 

This is because of all the chemicals and dyes that factories use when making fabrics. 

We do this to get rid of those things if needed. 

If needed, you say? 

Oh! Here is where the magic question comes.

Should you prewash fabric before sewing?

Yes and no. 

Not all fabrics need to be washed before sewing. 

For example, with the fabrics that are mostly made up of polyester such as swimming Lycra, there is a little to zero chance of anything bad happening. 

But if you were sewing anything with even a small percentage of natural fibers, then you should know how to prewash fabric.

These fabrics tend to shrink a lot or fade. 

By the way, that’s why I always buy extra yardage when I get cotton fabrics.

Do you use soap when pre-washing fabric? 

Absolutely! 

You should use everything you will use when you wash the final product. 

If you are going to put that dress into your regular cycle in the washing machine with soap and fabric softener. 

Then you should prewash the fabric with the same soap, fabric softener, and even the same cycle you usually use.

How do I know how to prewash each fabric? 

You should always take into consideration the special needs of the fabric you are going to use and how each one of them is supposed to be washed.

If you are a super responsable with your washing tags in clothes, use that to base your prewashing on.

But, if you are like me and just do the basic separation of colors and delicates then there is a little more simple.

So, this is the rule.

You have to give the same treatment of washing to the fabric as you are going to give to the final product that you are going to sew. 

This means that if you are going to put the clothes in the washing machine with cold water, then you must do the same with the fabric. 

If you are going to put it in a hot cycle in the washing machine and then put it in the dryer, then the fabric should go through the same thing. 

If you’re going to wash it by hand with a special, delicate soap… 

Well, I think you got what I am saying here.

You will love this Free Sewing Pattern: Gubbins No-show socks Pattern and tutorial.

What happens if you don’t prewash fabrics. 

As mentioned in the previous paragraphs, factories put many chemicals and dyes when making their fabrics. 

They do this to make their product look at their best on display. 

But the problem arises when you sew a pretty little red cotton dress without washing the fabric first.

Next thing you know, you are taking out of the washing machine a faded pink-is dress two sizes smaller and a lot of stained clothes. 

Releasing excess dyes and shrinking are just two of the consequences that not pre-washing your fabrics before sewing can have. 

We also have to take into account all harmful chemicals and dirt through which the fabric passes. 

This from the moment it starts to be manufactured until it reaches our hands. 

This is especially important if you have sensitive skin or allergies. 

Also if you are making anything for young kids or babies.

This will totally help: What is a Serger Machine? All you need to know.

How about cotton fabric? Do I need to wash cotton fabric before sewing? 

Yes, yes a million times yes. 

All fabrics that have natural fibers in them should always be pre-washed. 

I am talking about anything that has cotton, silk, linen… 

Because of their nature, fabrics put extra special “stuff” in these fabrics. 

For example, on fabrics like cotton and linen they use starch in, to make them stiffer. 

And when that starch is washed away the fabric will want to recover their natural form. 

AKA they will shrink to their natural size.

That’s why it is also a good tip that whenever you are going to make a project with natural fibers you buy a little bit extra. 

Just in case. 

I don’t want you to be lying your pattern on, just to find out it no longer fits in the fabric.

Finally,

How to prewash fabric without fraying?

Keeping fabric from fraying when you prewash it is very simple. 

You can use several techniques. 

One of them is making an overlock stitch with your serger machine. 

Which is my preferred method because of its efficiency.

You can also make a zigzag stitch along the width of the edge. 

In both of these cases, you can either unstitch the seams or simply cut away that part. 

The other thing you could do is use fabric glue or a fraying stopper on the edges of the fabric. Which is great if you are feeling lazy.

This will help the fraying at a good level and you will lose the least of it if you are cutting that part away.

I hope this information helps you to save all your future projects!

And if you have any further questions about how to prewash fabric, please drop them in the comments below and I’ll do my best to answer them all.

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