101 Guide to Interfacing Fabric

In a word, interfacing is used for stabilizing. It’s an important part of many sewing projects, especially in garments. As the name interfacing (or interlining, as it’s sometimes called) implies, it usually goes between layers of fashion fabric, where it provides invisible support.

What is Interfacing Used For?

1. Body

Think of the cuffs of a button down shirt. They have some stiffness, right? That’s courtesy of interfacing. Most of the time you use interfacing it’s going to be for collars, cuffs, and waistbands. Even if using a naturally crisp or heavy material, you will need interfacing in structural areas so that they are less limp than the rest of your garment. It’s all about relative body.

Similarly, interfacing can add structure to bags, costumes, or any other architectural detail. Say you want a silk evening clutch. Made out of only cloth, it would be like a pocket. It would sag and distort when you put things in it. Interfacing is what gives a purse the ability to hold a shape.

2. Reinforcement

Interfacing is used to reinforce areas of fabric that are cut/punctured in some way, or that have weight pulling on it—any area in which fabric might be stressed. The interfacing will reinforce the fabric so that it won’t tear. You’ll sometimes find it in button plackets on shirts, and you will always find it behind embroidery or beading.

3. Stabilizing stretch 

Even stretch garments have structure, and knit interfacing (which is mildly stretchy) will reinforce areas that fabric might need help holding a shape (such as around a neckline). You can also use woven interfacing to completely eliminate stretch, when necessary. (For example, if putting a zipper in a knit fabric, you must reinforce the seam with interfacing. Or if making a bag, which must be rigid, you can interface stretch fabric to make it suitable.)

The Different Types of Interfacing

There are several levels to navigate in selecting the proper interfacing. There are a lot of options but don’t worry, choosing the right interfacing pretty common sense. The basic rule of thumb is, match your fabric.

 

In a nutshell, first you decide whether you want fusible or sew-in. The difference is just what it sounds like. One irons onto your fabric, the other doesn’t. In most cases, which one you choose is just a matter of personal preference.

Fusible Interfacing: A Convenient Solution for Structure and Stability

Fusible interfacing, renowned for its practicality and efficiency, is a staple for projects involving fabrics like cotton, linen, or polyester that can handle heat. This heat-activated interfacing introduces structure to fabrics swiftly with a hot iron, eradicating the need for stitching. It’s an asset for projects requiring robustness like structured garments, bags, or home decor. Care must be taken to pair it with fabrics that endure the heat of application. Chosen wisely, fusible interfacing can uplift your sewing project’s quality, imparting a professional finish.

Sew-In Interfacing: The Ideal Partner for Delicate Fabrics

When working with delicate or heat-sensitive fabrics such as silk, lace, velvet, or certain synthetics, sew-in interfacing is the way to go. Unlike its fusible counterpart, sew-in interfacing does not rely on heat for application, making it perfect for fabrics that cannot bear high temperatures. This type of interfacing is meticulously stitched into the fabric, allowing for precision and a greater degree of control during application. The process may require more time compared to fusible interfacing, but the end result – a beautifully structured yet naturally draped garment – is undeniably worth it. With sew-in interfacing, fabrics retain their original feel and drape, augmented with additional support and structure where needed. This type of interfacing truly shines when used in projects where fabric preservation and a soft, natural finish are essential.

Fusible vs Sew-In Interfacing:

Choosing between fusible and sew-in interfacing is about more than just the application process—it’s about recognizing the needs of your fabric and the project at hand. Fusible interfacing, with its heat-activated adhesive, provides a fast and firm bond, excellent for fabrics that can withstand the heat of an iron. Its ability to quickly add rigidity to a project makes it a go-to choice for many sewers. On the other hand, sew-in interfacing, which is carefully sewn onto the fabric, is perfect for delicate or heat-sensitive materials. While it may require a bit more time and effort in the application process, it preserves the fabric’s natural drape and feel while still providing the necessary support. Understanding the strengths and uses of each type of interfacing is crucial to achieving the best results in your sewing projects.

Next, do you want woven, non-woven, or knit? A 4-way knit fabric requires a 4-way knit fusible, if you want to maintain stretch. Otherwise, again, which you choose is basically a matter of preference. (Non-woven is ideal for things like appliqués, because you don’t need to mind a grain line. This allows you to turn a shape any direction on the fusible fabric in order to get the best fit, when cutting.)

Woven Interfacing: Seamlessly Complementing Your Fabric

Woven interfacing, with its well-defined grain lines mirroring regular woven fabric, offers a subtlety that makes it a perfect choice for projects requiring a natural look and feel. It effortlessly blends with your fabric, maintaining its inherent drape and texture while providing the necessary structure and support. The magic of woven interfacing is in its ability to work quietly in the background, enhancing the fabric’s natural characteristics without stealing the show. Ideal for tailored clothing and where a smooth, professional finish is desired, woven interfacing adds strength without compromising on the fabric’s natural charm. It’s an example of how strength and subtlety can harmoniously coexist in the world of sewing.

Non-Woven Interfacing: The Versatile Choice for Any Project

Non-woven interfacing is a powerhouse in the realm of sewing projects due to its unique composition and versatility. Made by bonding fibers together, it lacks a directional grain line, meaning it can be cut in any direction without fear of fraying or unravelling. This feature makes it exceptionally user-friendly and adaptable to a variety of projects. Whether you’re working on a garment, accessory, or home décor item, non-woven interfacing effortlessly caters to your project’s needs. The absence of grain lines offers a level of flexibility that is both liberating and practical, making non-woven interfacing a reliable choice for sewers of all skill levels. With non-woven interfacing, you can focus on your creativity and craft without being bound by restrictions.

Knit Interfacing: The Perfect Balance of Stretch and Stability

When it comes to working with knit or stretchy fabrics, knit interfacing is the perfect companion. It boasts a unique ability to maintain a fabric’s inherent elasticity while adding necessary structure and support. Unlike traditional interfacings, knit interfacing moves with the fabric, allowing for the preservation of stretch and mobility in the final product. This is particularly important in garments like t-shirts, swimwear, or leggings, where flexibility is paramount. Despite its accommodating nature, knit interfacing also provides subtle firmness, preventing the fabric from losing its shape over time. It is this harmonious blend of flexibility and stability that makes knit interfacing a highly valued asset in the sewing world. With knit interfacing, you can create stretchy, durable projects without sacrificing comfort or quality.

How to Choose the Right Interfacing for Your Project

Choosing the correct interfacing for your sewing project can often seem like a daunting task, especially considering the plethora of options available. However, by keeping a few key factors in mind, you can navigate this process more easily and select the interfacing that best suits your needs.

The first consideration is your fabric’s weight.

This is crucial as lightweight fabrics generally require a lightweight interfacing to maintain their drape and flow. In contrast, heavier fabrics can handle a sturdier interfacing, which can provide the structure these materials need. Pairing a heavyweight interfacing with a delicate fabric could lead to undesirable stiffness, while a lightweight interfacing might not provide enough support for a robust fabric.

Next, consider the type of fabric you’re using.

Some materials, such as synthetic ones, may not tolerate the heat of a fusible interfacing and would fare better with a sew-in version. On the other hand, fabrics that can withstand high temperatures may benefit from the quick application and firm bond of fusible interfacing.

Evaluate Your Project’s Function

A bag or a collar that needs to hold its shape might require firmer interfacing, whereas a blouse or dress might benefit from a softer, more flexible interfacing to preserve the fabric’s movement.

Remember to Test First!

Lastly, always test your interfacing on a scrap of your project’s fabric. This allows you to see firsthand how the interfacing interacts with your fabric, ensuring that they work together harmoniously before committing to the final application.

Selecting the right interfacing is a thoughtful process that requires understanding your fabric, your project, and how these two elements intersect. With these considerations in mind, you’ll be better equipped to choose an interfacing that enhances the overall quality of your project.

Choosing the Appropriate Interfacing Weight

Choosing the appropriate weight of your interfacing fabric is an integral step in the sewing process. The interfacing’s weight can profoundly affect your final project’s look, feel, and functionality. So, how does one go about selecting the right weight?
The rule of thumb is that the weight of the interfacing should ideally match, or be slightly less than, the fabric you’re using.

This guideline helps maintain balance and preserves the fabric’s natural attributes without distorting its original form or adding unnecessary bulkiness.

For lightweight fabrics, choose lightweight interfacing.

These delicate fabrics need a supportive yet unobtrusive interfacing that won’t weigh them down or affect their soft drape. Light interfacing is perfect for materials like silk or chiffon and is ideal for creating flowing garments or delicate decor pieces.

Medium-weight Interfacing is the most versatile

Medium-weight interfacing is a versatile choice, compatible with a wide range of fabrics. It provides a balance of rigidity and flexibility, perfect for most common fabric types like cotton or linen. Medium interfacing works well with fabrics used in crafting shirts, dresses, or household items that need a little structure but still maintain a soft, natural feel.

Heavyweight interfacing pairs well with robust, heavy-duty fabrics.

Materials like denim, canvas, or upholstery fabric benefit from the sturdiness that heavy interfacing provides. It ensures these fabrics keep their form and provides a robust structure suitable for crafting bags, jackets, or upholstery items.

Understanding the weight of your fabric and the specific needs of your project is key to choosing the right interfacing. Making a thoughtful selection can significantly enhance your sewing project’s quality and longevity, leading to a professional-looking and durable end product.

Different Types of Interfacing in Action

Here are some kinds of interfacing in action, so that you can see the effect they have on fabric.

I’ve used the same lightweight cotton for each demo. On the left is un-interfaced fabric. On the right is the swatch with interfacing.

You can see how the drape of the cotton is unchanged with the lightest interfacings, has just slightly more body with the medium, and ranges from stiff to outright creaseable with the heavyweights. Below is an example (on a swatch of twill) of how tearaway works:

FAQs About Interfacing