Sewing interfacing is one of those topics that's easy to overlook, whether you're new to sewing or have years of experience. And yet it can have a major impact on the outcome of a project.
Interfacing is the support that helps fabric hold its shape, adds structure where needed, and gives projects a professional finish.
Here, we discuss what interfacing is, why you shouldn't skip it, the different types of interfacing, and how to choose the right one.
What is interfacing and why is it important?
Interfacing is a textile layer that is used to add structure, stability, and body to fabric. Done well, you don't even notice it while wearing a garment. It's there doing work behind the scenes to add structure, body, and strength where needed. Skip it, and garments tend to stretch, distort, wear out quickly, and just won't have the look you expect.
Interfacing is generally used to stabilise specific areas of a garment like facings, collars, waistbands, or button plackets. It's used just in the places that need extra support.
Think of a light linen top with a faced neckline. Linen can have a fair amount of stretch on the bias, so over time a neckline that isn't reinforced might lose its shape and stretch out. A lightweight interfacing applied to the facing pieces before sewing will stabilise the fabric, keeping the neckline smooth, and helping it to hold its intended shape.
Now, consider a wool coat with a button band. Every time the coat is buttoned and unbuttoned, the band takes stress and strain. Without interfacing, the band and buttonholes can stretch and distort. Interfacing reinforces the button strip so that the buttonholes remain neat and stable, and the front of the coat retains its structure.
Other places you may see interfacing include bags and hats, and at Twig + Tale, we use interfacing in some pretty innovative ways, such as our soft-structured Wings Collection and Nature Baskets.
Fusible vs. sew-in interfacing
Fusible interfacing has a heat-activated adhesive on one side so that it can be adhered to fabric. The adhesive side often appears shinier and has little dots of glue. Once fused to fabric with a hot iron, the two layers should, theoretically, be bonded together permanently. When everything works properly, it is easy and fast to apply.
There are some pitfalls to fusible interfacing, however. Sometimes it does not stick properly and can peel and bubble. Sometimes the adhesive can feel a bit stiff. Different brands of interfacing may have different instructions for pressing. There are some fabrics that just aren't suitable for use with fusible interfacing, such as fabrics with lots of texture, sheer fabric, or fabric that could be damaged by high heat or pressing.
Tips: If your interfacing comes with instructions (often a piece of tissue paper that is folded in with the interfacing on the bolt), keep them for reference! Always use a press cloth when applying fusible interfacing (to avoid gunking up your iron), and always test on a scrap of fabric first.
Sew-in interfacing is stitched into a garment rather than fused. It can be basted to the fabric first or layered directly with the fabric and sewn right into the seam allowances during construction (treating two layers as one), so that it will sit between the fabric layers and add structure without any adhesive. It's a great choice for couture sewing techniques, and because there's no glue involved, sew-in interfacing tends to move and drape more naturally. It can be used with any type of fabric, so is the natural choice for fabrics that don't work with fusible interfacing.
The main drawback of sew-in interfacing is that it tends to be more time consuming to use, and care must be taken to ensure it doesn't shift around when sewing, since it's a separate layer.
Our take on fusible vs. sew-in? It really depends on your project, fabric choice, and personal preference. In most cases, either can work. Occasionally, you'll find an application that specifies fusible or sew-in (like when sewing Wings). But for most garment sewing, it's really up to you. Chances are, you'll want to keep both on hand for different applications.
Tip: different brands of interfacing can vary widely in quality, so if you find one that you like, stock up!
Types of interfacing
The following types of interfacing - non-woven, woven, and knit - are available in fusible and non-fusible options, and in a variety of weights.
Non-woven interfacing
Non-woven interfacing is made from synthetic fibres that are bonded together through heat, pressure, or chemicals, similar to the structure of craft felt. As a result, it doesn't have a grain, so it can be cut any which way. It has a rather papery feel and is very easy to cut. It's also readily available and inexpensive.
We tend to use non-woven interfacing primarily in projects that won't be washed often - projects where we want a heavier, stiffer interfacing. At T+T, we use non-woven interfacing for Wings, Nature Baskets, and hats.
However, it's not generally a great choice for garment sewing. It often feels quite stiff (even the lighter weights) and repeated washing and wearing can cause it to break down, separate, or bubble. As the interfacing breaks down, it is no longer able to provide the intended structure, and the garment will suffer.
Non-woven interfacing definitely has its place in our sewing rooms, but we tend to avoid it for garments.
Woven interfacing
Woven interfacing is made of synthetic or natural materials like cotton, and can be identified by its construction with woven warp and weft threads, like fabric. It has a grainline, and like fabric, the pattern pieces must be cut on the correct grainline for a garment to hang properly.
In most cases, woven interfacing is a much better option for garment sewing than non-woven. It tends to have a more natural drape and, when grainlines are matched, it works in harmony with the fabric. It tends to be more durable that non-woven - the woven structure holds up better to repeated laundering. It can also feel better when worn, breathing more like fabric.
The grain requirement is the most significant added consideration - you can't simply cut woven interfacing in any direction the way you can with non-woven, which means you need to be more deliberate when laying out your pieces. It also tends to be more expensive than non-woven.
Woven interfacing is generally the best choice for garment sewing applications that need structure that can hold up to wear and washing.
Knit interfacing
Knit interfacing is made from looped, interlocked fibers that allow it to stretch. It is most often used with stretch fabrics, adding stability, body, and stretch recovery, while allowing the fabric to do what it is supposed to do.
Knit interfacing provides less firm structure than woven interfacing, which is a reasonable trade-off in stretch garment construction but makes it a poor choice anywhere you need a crisp, stable result. It can also be slightly trickier to handle during application since the stretch means it needs to be kept relaxed and flat.
Twig + Tale patterns are primarily designed for non-stretch, woven fabrics, so the application of knit interfacing is limited. However, knit interfacing is still a better option that non-woven for anyone who is sewing a garment and finds themselves without woven interfacing on hand.
How to choose the right interfacing for your project
Match the weight - the interfacing should match the weight of the fabric. A lightweight fabric should use a lightweight interfacing. A thick, heavy fabric should use a heavier interfacing. There is some nuance to this, depending on the result you're looking for, however generally speaking, the interfacing should be the same weight, or slightly lighter, than the fabric.
Match the colour - interfacing usually comes in white and charcoal/black, so choose the closest match for your fabric so that the interfacing doesn't shine through. Test it out by layering the fabric over the interfacing in good light, just to make sure the combination works.
Match the interfacing type to the fabric structure - generally speaking, woven interfacing works best for woven fabric and knit interfacing works for knit fabric. This ensures the interfacing moves in a way that is compatible with the fabric.
Test the combination - cut a small sample of the interfacing and fabric and, if applicable, fuse them together. Then check the drape, stability, and hand. Does it feel right for your project? Will it be comfortable to wear?
Alternatives to interfacing
For those who prefer to work with natural fibres, fabrics like cotton lawn, calico/muslin, and poplin have been used as interfacing for centuries. They offer some appealing advantages over manufactured interfacing - they're breathable, washable, and can give a more natural drape and hand to a finished garment. If you'd like to learn more, we have another article that discusses the topic here: How to Use Fabric as Interfacing - Natural Fibre Alternatives.
There are a surprising number of considerations when choosing interfacing, and we hope that this guide helps you to feel more confident for your next project. If you have any questions about choosing interfacing, please feel free to join us in the Twig + Tale Treehouse Community or the Twig + Tale Chat Facebook group, where we're always happy to offer support.
