Fusible Interfacing in Sewing by Sew DIY

Interfacing in Sewing: What Is It & When Do I Use It?

Today, we’re diving into the transformative world of “interfacing in sewing”. If you’ve ever marveled at the structure of a crisp collar or the smooth finish of a tailored garment, interfacing is the unsung hero behind the scenes. But, it can feel daunting.

Fusible vs. Sew-In?

Medium weight knit interfacing?

Non-woven interfacing vs woven interfacing?


There are enough articles and videos discussing the many types of interfacing to make your head spin.

By the end of this article, you should better understand the role interfacing plays in your projects, as well as which interfacing to use for each garment you make.

Let’s dig in!

Understanding Interfacing

Sew Anastasia on YouTube

Interfacing is a type of fabric that’s used to add rigidity, structure, and support to certain areas of a garment, such as collars, cuffs, and waistbands. Think of it as the skeleton that gives shape to your sewing project. There are primarily two types of interfacing fabric:

  • Fusible Interfacing: This type has a heat-activated adhesive on one side. When you apply heat with an iron, it bonds (or fuses) with the fabric. It’s a favorite among many because of its ease of use. However, it’s essential to choose the right weight to match your main fabric, or you risk altering the fabric’s drape.
  • Sew-in Interfacing: As the name suggests, this sew in interfacing is sewn onto the fabric. It’s ideal for fabrics that cannot withstand the heat of an iron (think satin or fur) or for very textured fabrics (like pleated or napped fabrics) where the adhesive might not bond uniformly.

While these are the two most common types of interfacing they aren’t the on ly types of interfacing there are. You may also find:

  • Woven Interfacing: This is a versatile type of interfacing made from woven fabric. It adds medium-weight support and is suitable for a wide range of fabrics and projects.
  • Non-Woven Interfacing: Non-woven interfacing is made from synthetic fibers and is often used for lightweight support. It doesn’t have a grain, making it easy to cut and use.
  • Knit Interfacing: Knit interfacing is designed for use with stretchy or knit fabrics. It provides stability while allowing the fabric to maintain its stretch.
  • Sheer or Lightweight Interfacing: This type of interfacing adds minimal structure and is often used in delicate fabrics like silk or chiffon to prevent stretching and provide stability.
  • Medium weight and Heavy weight Interfacing: These interfacing types are used when you need significant support and structure, such as in collars, cuffs, or bag linings.
  • Interfacing with Stretch: Some interfacing has stretch properties and is suitable for stretch fabrics or areas of a garment that need to maintain stretch, like waistbands on knit garments.
  • Fusible Web or Wonder Under: This is a lightweight, adhesive-backed web used for bonding two layers of fabric together. It’s commonly used in appliqué work.
  • Water-Soluble or Wash-Away Interfacing: This type of interfacing dissolves in water, leaving no trace. It’s used for stabilizing delicate fabrics during embroidery or lace-making.
  • Bias-Cut Interfacing: Bias-cut interfacing is cut on the bias (at a 45-degree angle to the fabric’s grain) and provides more flexibility and drape, making it suitable for curved areas like armholes.
  • Double-Sided Fusible Interfacing: This type has adhesive on both sides and is used for bonding two layers of fabric together, often in crafts or quilting.
  • Stabilizer: While not technically interfacing, stabilizers are used to prevent stretching or puckering during embroidery or when sewing on difficult fabrics.

Choosing the Right Interfacing

Choosing the right interfacing can feel SO overwhelming at times. For example, the weight of the interfacing I used for this Agua Bendita dupe is different than I used for this patchwork denim jacket.

Adding the Interfacing and Button Placket to my DIY Patchwork Denim Jacket

Here’s a breakdown to guide you:

  • By Fabric Type:
    • Woven Interfacing is best suited for woven fabric. It has a grain line, just like regular woven fabric, and it’s essential to match the interfacing’s grain to the fabric’s grain.
    • Knit Interfacing is designed for knit fabrics. It retains some stretch, ensuring that the fabric’s stretch properties aren’t compromised.
    • Non-Woven Interfacing is versatile and doesn’t have a grain line, making it suitable for any direction.
  • By Weight:
    • Lightweight Interfacing: Ideal for delicate fabrics like silk or lightweight cotton. It provides structure without adding bulk.
    • Medium Weight Interfacing: Perfect for regular woven fabric or medium weight knit fabrics. It offers more support than its lightweight counterpart.
    • Heavyweight Interfacing: Used for heavyweight fabric or when a stiff outcome is desired, like in belts or structured bags.
  • By Application:
    • Fusible: Requires an iron to bond with the fabric.
    • Sew-in: Needs to be sewn, ideal for fabrics that can’t handle heat.

How to Use Fusible Interfacing

Using fusible interfacing is a straightforward process, but precision is key. Here’s a step-by-step guide:

  1. Cut the Interfacing: Always cut the interfacing a bit lighter than your main fabric to ensure a smooth finish.
  2. Position the Fusible Side: The adhesive side should be against the wrong side of your fabric.
  3. Protect Your Fabric: Use a pressing cloth to prevent any adhesive residue from getting onto your iron.
  4. Press: With your ironing board at the ready, press the interfacing onto your fabric. Remember, lift and press, don’t slide the iron.

Interfacing Tips for Different Fabrics

Different fabrics have unique needs, and interfacing can help address those:

  • Stretch Fabrics: Always use a stretch interfacing to maintain the fabric’s elasticity. Remember, the goal is to add structure without compromising the fabric’s inherent properties.
  • Textured Fabrics: For very textured fabrics, sew-in interfacing is your best bet. The uneven surface might make it challenging for fusible interfacing to adhere uniformly.
  • Delicate Fabrics: Lightweight interfacing is a must. The last thing you want is to weigh down your delicate fabric with heavy interfacing.

Common Mistakes and How to Avoid Them

Love this explainer video from Evelyn Wood

Interfacing, though transformative, can be tricky. Here are some pitfalls to avoid:

  • Mismatched Weight: Always match the weight of the interfacing to the fabric. Using heavyweight interfacing on a delicate fabric can ruin its drape.
  • Skipping the Test: Before applying interfacing to your main fabric, always test on a scrap piece. This step ensures compatibility and prevents potential disasters.
  • Ignoring the Grain: For woven interfacing, always match the grain of the interfacing to the fabric. This alignment ensures a smooth finish and prevents puckering.

Frequently Asked Questions

Do you have to use interfacing when sewing?

Interfacing is not always mandatory in sewing, but it serves a crucial purpose in enhancing the stability and structure of specific garment areas. Its use depends on factors like the fabric type and the desired outcome of the project. Lightweight or delicate fabrics often benefit from interfacing to add support, while heavier fabrics may not require it. Evaluate your project’s needs and fabric choice to determine whether interfacing is necessary

Does interfacing make fabric stiff?

Technically, yes. Interfacing can make fabric stiff, but the degree of stiffness depends on the type of interfacing used and the amount applied. Interfacing is designed to add structure and stability to fabric, so it may create a firmer or more rigid feel in the areas where it’s applied. However, you can choose from various types of interfacing, including lightweight interfacing, medium weight interfacing, and heavyweight interfacing, to achieve the desired level of stiffness or flexibility for your project.

What can you use instead of interfacing?

If you don’t have interfacing or prefer an alternative, several common substitutes can be used in sewing:

  1. Muslin or Lightweight Fabric: You can use a layer of muslin or a lightweight fabric as an interfacing substitute. Simply cut it to match the pattern piece that requires interfacing and baste it to the main fabric.
  2. Fusible Web or Adhesive: Fusible webbing, such as Heat ‘n Bond or Wonder Under, can temporarily add stiffness. Iron it onto the fabric following the manufacturer’s instructions.
  3. Organza or Tulle: These sheer fabrics can work as a lightweight stabilizer, especially for delicate fabrics or crafts.
  4. Pellon Fabric Stabilizer: Pellon offers various fabric stabilizers suitable for different projects, which can serve as interfacing alternatives.
  5. Double-Sided Tape: For temporary stiffening or adhesive properties, double-sided tape can be applied to the fabric’s wrong side.
  6. Extra Fabric Layers: Adding extra layers of the same fabric can provide additional support and structure in certain cases.

Remember that the effectiveness of these substitutes can vary depending on the project and fabric type. It’s a good practice to test a small area before committing to an alternative to ensure it meets your specific needs.

SewingIsCool has more examples of interfacing alternatives if you’d like to read more.

How do you use interfacing when sewing?

  1. Choose the right interfacing for your project and fabric.
  2. Cut the interfacing to match your fabric piece.
  3. If it’s fusible, iron it onto the fabric’s wrong side following the temperature instructions. If it’s sew-in, stitch it to your fabric.
  4. Once it’s attached, just continue sewing your project as usual. Interfacing helps things like collars and cuffs keep their shape and look more polished

What is bonded interfacing?

Bonded interfacing is a handy tool in your sewing arsenal. It’s got an adhesive side that activates with heat, typically from an iron. You can use it to give your collars, cuffs, and other fabric parts some extra stability and structure. It’s user-friendly, and once it’s ironed on, it’s there to stay even after washing. So, it’s a smart choice to make your sewing projects look polished and professional.

Can you use fusible interfacing on knits?

Yes, you can use fusible interfacing on knits, but it’s important to choose the right type of interfacing and follow some specific guidelines:

  1. Select Knit-Friendly Interfacing: Opt for a knit or stretch fusible interfacing specifically designed for use with knitted fabrics. These interfacing types are more flexible and compatible with the stretch of knit fabrics.
  2. Test on a Scrap: Before applying the interfacing to your main knit fabric, it’s advisable to test it on a scrap piece of the same knit material. This allows you to determine the appropriate heat setting and ironing time without risking damage to your project.
  3. Use a Pressing Cloth: To protect your knit fabric from direct heat and potential damage, place a pressing cloth or a piece of lightweight cotton fabric between the iron and the interfacing. This prevents the interfacing from sticking to the iron or distorting the knit fabric.
  4. Apply Gentle Heat and Pressure: When fusing the interfacing to the knit, use a low to medium heat setting on your iron, and apply gentle, even pressure. Avoid using high heat, which can cause the knit fabric to stretch or warp.
  5. Allow Time to Cool: After applying the interfacing, let the fabric cool completely before handling it. This helps the adhesive bond securely with the knit fabric.

Using the appropriate type of fusible interfacing designed for knits can add stability to your knit projects, reinforce areas like necklines or hems, and prevent stretching or distortion. Just remember to take precautions to ensure that the heat from the iron doesn’t damage the delicate knit fabric


Interfacing, though often overlooked, is the backbone of many sewing projects. It’s the difference between a saggy collar and a crisp one, a floppy bag and a structured one. As you embark on your sewing projects, remember to give interfacing the attention it deserves. It might seem like just another step in the sewing process, but it’s a game-changer.

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As always, thank you so much for reading, and happy sewing!

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