Sewing Interfacing: What You Need To Know

You may have heard the world “interfacing” floating around in certain sewing circles and found yourself confused by what it means. The dictionary defines “interface” as “a surface regarded as the common boundary of two bodies, spaces, or phases,” but that’s not what seamstresses are referring to when they use this word. In the sewing world, interfacing is a woven or non-woven textile that is used to stiffen and add structure to certain areas of garments. It is fused or sewn to the wrong side of the fabric in places such as collars, cuffs, and underneath buttoned areas.

Interfacing is invaluable to a garment and provides invisible support to fragile areas. There isn’t much known about the history of interfacing. Fusible interfacings became available for home sewers in the late 1960s, but other types of interfacing were being used well before then. This can be seen when looking at garments from the 1930s and 1940s, with their flexible collars and large, stiff bows. Usually, interfacing instructions weren’t included in the designs, but rather something that seamstresses simply knew to do for support in garments they deemed necessary. 

In any case, interfacing is an extremely useful tool that will help you make your garments look crisp, clean, and professional. In this article, we’ll go over when and why to use interfacing, the types of interfacing, as well as how to apply them. 

Why Should I Use Interfacing?

There are a variety of reasons one might decide to put interfacing in their garment. The main reason is that it provides shape and structure to garments. This will help you sculpt a cleaner silhouette and make the garment look more professional. Interfacing can also provide body to flimsier fabrics, making them look fuller, and giving them movement. 

Interfacing is used for support and durability to certain areas of the garment, like stress points or other places that are prone to tearing. Interfacing is commonly used to stabilize buttons and support buttonholes.

Interfacing can also come in handy for supporting certain design elements, such as embroidery or embellishment. If you have a heavily embroidered area that weighs down the fabric of the garment, adding interfacing is a great way to add some extra support. 

Types Of Interfacing 

Once you’ve determined which parts of your garment require extra support and why, you can begin the process of selecting and applying the correct interfacing. There are about six main types of interfacing, all of which are characterized by the method of application and the structure. 

Sew-in Interfacings 

Just like the name suggests, sew-in interfacings have to be sewn in, either by hand or by machine. There are endless types of sew-in interfacing, and the material can be woven or non-woven. Sew-in interfacings can be lightweight, like tulles and nets, or heavy, like muslin or flannel, depending on the look you want to achieve. Sew-in interfacings can give the garment a freer, more flexible look, as opposed to fusible interfacings.

Fusible Interfacings 

Fusible interfacings come with dried glue or resin on one or both sides that is activated with heat, moisture, or pressure. Fusible interfacings stick to the garment on their own without needing to be sewn in place. Fusible interfacings aren’t a good choice for fabrics that are sensitive to heat or pressure, like leathers, furs, vinyl, or velvets.

Just like sew-in interfacings, fusible interfacings are available in a variety of materials and can be woven or non-woven. You’ll select the material for your fusible interfacing based on the material of your garment and your desired level of support. Fusible interfacings are easier to apply than sew-in but can sometimes leave the garment stiff. 

Double-sided Fusible Interfacings 

Just like traditional fusible interfacings, double-sided fusible interfacings come with a glue or resin attached. However, as the name suggests, the glue is on both sides, so the interfacing can attach to the fabric on both its front and back. This is great for providing support in between fabric layers on your garment.

Woven Interfacings

Woven interfacings are made like traditional fabric by weaving yarn together at right angles. They will have a cross-grain, a lengthwise grain, and a bias. Like all woven fabrics, they have stretch along the bias line, so it’s important to cut along the grainline for sturdy interfacing. 

Non-Woven Interfacings

Non-woven interfacings are made with fibers that are bonded together with either heat or chemicals. They have no visible cross-grain, lengthwise grain, or bias, so they can be cut in any direction. Non-woven interfacings work well for small areas or ones that require the interfacing to be cut into a complex shape, as there is no risk of unraveling. 

Knit Interfacings 

Knit interfacings have a bit more stretch to them than other types of interfacings, and they work well when used on knit garments. Knit interfacings are made in a few different ways. Different types of knit interfacings can be stretchier in either the length, the width, or the bias. 

How To Apply Interfacing 

Once you’ve determined the type of interfacing you need, you can prepare to apply it. Interfacing will be applied before you sew the fabric pieces of your garment together. Before application, we recommend pre-washing both your interfacing and your fabric to ensure that they don’t shrink at different rates. This can cause wrinkling on the outside of your garment.

Next, we advise that you test a small piece of your interfacing on a scrap of the fabric your garment is made of. Interfacing can feel different when it’s applied or fused to fabric. Make sure it has the correct level of stiffness that your garment requires. Once you’ve determined you have the correct type of interfacing, you’re ready to apply.

Applying Sew-in Interfacings

To apply sew-in interfacing, you’ll need your interfacing, your fabric, scissors, pins, and a sewing machine. 

To begin, cut out your interfacing to shape. You’ll want it to be large enough to provide support, but not so large that it pokes out from the wrong side of your garment and is visible from the outside.

Now, pin your interfacing to the wrong side of your garment. There shouldn’t be a right side or a wrong side to sew-in interfacing, so you won’t have to worry about that. Apply straight pins around the perimeter of the interfacing.

Once at your sewing machine, select the basting stitch, so you’re using a straight stitch at the longest stitch length possible. Now, baste around the perimeter of the interfacing, making sure to stay within your garment’s seam allowance, which is usually about ⅝ of an inch. 

Once you’ve assembled your garment, if your basting stitches are visible, you can remove them, as the interfacing will now be held in place by the regular stitching in your piece. 

Applying Fusible Interfacings

To apply fusible interfacings, you’ll need your fusible interfacing, your fabric, an iron, scissors, and pins. You’ll also need either an ironing board or a wool pressing mat to protect your table. 

To begin, cut your fusible interfacing to the size of your fabric piece. Ensure that the shiny side of the interfacing is against the wrong side of the fabric. Pin it in place, but pin it an inch or two away from the edge. Now, you’re going to trim the edges of your fusible interfacing, eliminating any parts that overlap with your seam allowances. This reduces the bulk and makes the fabric pieces easier to sew after the interfacing is applied. If you’re using lightweight interfacing, it’s not necessary to trim off the excess.

Now, place the interfacing and the fabric down on your pressing surface, and remove the pins. Place a spare piece of cloth down over the interfacing to prevent it from sticking to the iron. Ensuring your iron is set to the instructed temperature, begin pressing the interfacing on. Press the iron down firmly, then lift, then press again. Avoid gliding the iron across the surface, as this can cause the interfacing to shift on the surface of the fabric.

Once you’ve pressed the entire surface, remove the cloth and allow the interfacing to cool completely before you sew with your reinforced fabric piece. 

Conclusion 

Learning to use interfacing properly is so important for providing stability, support, and durability to garments. There are many different types of interfacing, each of which is best suited to different projects. Once you’ve mastered the art of interfacing application, you can apply it to any garment that needs a little extra support.

If you’re passionate about all things sewing, come join the Love Sew community by visiting us online. We offer helpful tutorials, tips, tricks, and sewing gadgets that will turn any seamstress from a novice to a master in no time at all.

 

Sources:

Interface | Definition of Interface at Dictionary.com

Interfacing: Invaluable and Invisible | uen.org

INTERFACINGS for Sewing | Palmer Pletsch Sewing Workshops, Patterns and Books