How To Prewash Fabric For Sewing: Do This First

Last Updated on 6 months by Susan Mayrich

This article will teach you how to prewash fabric for sewing in three steps. We start by differentiating materials, then decide if you can hand wash or machine wash them. You’ll also know why prewashing is important before sewing. 

how to prewash fabric for sewing

Another practice that you can also do pre-sewing is checking your needles. You must replace broken needles or consider learning how to sharpen sewing needles once they get blunt. 


How Do You Wash Fabric Before Sewing?


Step 1. Determine the material

Determine if your fabric is synthetic or natural because natural fibers will shrink, and synthetic fibers are prone to color bleed, especially red fabrics. Then, check the label of the fabric for its washing instructions or test a small scrap yourself. Cut a 4 by 4-inch square of test fabric, and hand wash or machine wash it with white scrap fabric to check for color transfer. 

The 4 by 4-inch fabric can retain its measurement, meaning it has no shrinkage. On the other hand, it can turn into a 6 by 3.6-inch, which means there’s 10% shrinkage or 25% shrinkage if it got as small as 3 by 3 inches. Remember which fabrics shrink and wash them separately, similar to the materials that discolor the white scrap fabric. 


Step 2. Hand wash or machine wash

Cotton can be warm machine washed while polyester and rayon can be cool machine washed. Silk should be hand washed in warm water, while stretchy materials like Spandex and Lycra should be cold hand washed. And finally, linen can be hand washed or cold machine washed. 


Step 3. Dry the fabric

Please avoid using the dryer to dry the prewashed fabrics because it can over shrink them unless their label indicates that it’s safe to do so. The safest way to dry prewashed fabrics for sewing is to air dry them over the clothesline. Then, press the materials with water spray gently to remove the wrinkles.

Finally, trim off the fraying before cutting the fabric for sewing. Read what is grainline in sewing to further help you in cutting your fabrics for sewing.


What Is prewashing?

Prewashing the fabric means hand washing or machine washing the material before sewing. It is also sometimes synonymous with pre-shrinking the fabric since washing it will reveal if the material will shrink. It’s a step before sewing that you must do to ensure that the finished project will have your planned size or fit. 


Should I Wash Fabric Before Sewing? 


To preshrink

Natural fibers can shrink around 5 to 10%, which means the project’s final size can change if you didn’t wash the fabrics before sewing. This is especially crucial when sewing clothing and garments. But while some materials don’t shrink higher than 10%, prewashing them can still offer benefits such as addressing color bleeding and cleaning the fabric free from dirt and chemicals.  


Prevent staining

Synthetic fabrics, especially those that come in bold colors like red, are prone to bleeding. This means you risk staining or changing lighter-colored items when washed with them. Some might even look faded after the washing, so save yourself the trouble by pre-determining which fabrics bleed. 


To remove chemicals

Finally, prewashing will clean out the material before sewing. It might undergo various chemical and dye treatments or collect dirt throughout the process. While fabric chemicals are not dangerously harmful, some people have sensitive skin and can still react to them. 


Do You Use Detergent When Prewashing Fabric?

Machine washable fabrics should be safe to be washed with detergent. However, use a smaller amount to what you’ll typically use or test your fabric with the detergent for fading and other reactions. And as for materials that must be hand-washed, use a bit of mild soap while gently washing them. 


How To Wash Cotton Fabric Before Sewing

Cotton is prone to shrinkage, and it can be warm washed with a machine. You can also wash it by hand in cold water, then dry the fabric in the line to remove wrinkles. Other materials that are prone to shrinking are flannel and knitted fabrics, so use warm water when prewashing them. 


How Do You Keep Fabric From Fraying When Prewashing?

Serge the fabric edges before prewashing them to prevent the material from fraying excessively. To avoid fabric bunching, you can use a serger or sew with wide zigzag stitches or a 3-step zigzag. Reduce fraying with pinking shears or pre-fray the fabric yourself by pulling a ⅜-inch of the weft thread selvage to selvage. 

If you have no serger, read this tutorial on how to serge with a sewing machine


What Stitch Do I Use To Keep Fabric From Fraying?

Finishing the seams with the zigzag stitch can help prevent fraying. You can also make overcast stitches on the fabric’s raw edge to keep it from unraveling if you’re sewing by hand. And if you don’t want to sew, you can sandwich the edges with bias tape. 



Was this article helpful? To recap how to prewash fabric for sewing, you must test a square piece and determine if you can hand wash or machine wash the material. Remember to use mild soap as well and then air dry the washed fabrics afterward. 

As for the fraying, serge the edges or zigzag stitch them before sewing. We hope you learned a lot; leave us a question if you have any. 

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