What is Interfacing in Sewing? (3 Cheat Sheets Included)

The difference between handmade and homemade can often be summed up in one word: interfacing.

What is interfacing used for in sewing? It’s a special fabric that adds structure to projects, from garments to handbags, and can give your make that professional finish that takes it to the next level. I’ve even used it as a little “cheat” to add a soft feel to the back of sequin fabric and help hold the finicky material in place while sewing it.

If you’ve been hearing about sewing interfacing, but are not exactly sure what it is or if you need it, here is an “Interfacing 101” article just for you. Read on for how to choose, purchase and use this fabulous material to its best ability.

What is Interfacing in Sewing?

Interfacing is an additional layer added to the unseen side of fabric (aka the “wrong side”) in high-wear areas (think shirt cuffs and waistbands) to add more support, structure and/or durability.

In short, interfacing helps these areas keep their shape. 

This material is used to:
– Make certain areas more rigid or stiff, like in a shirt cuff or collar
– Add durability to an area, like on a front placket (where buttons are sewn on a shirt)
– Provide sturdy structure to a project, like in a structured handbag or fabric box
– Provide shape over time and minimize stretching, as with knit garments

Interfacing comes in two different types; fusible and sew in. It also comes in different weaves (knit, woven, nonwoven, foam), weights (light, medium, heavy) and colors (usually white/cream and black).

As a rule of thumb, the intended use of the project determines the weight of the interfacing that should be used. For example, a cuff needs stiffer interfacing than a soft collar. The heavier the main fabric is, the heavier the interfacing should be.

You can find this material at fabric stores or online. It is sold on bolts and also as pre-set quantities by the package. For instance, I just purchased a 20” x 1 yd of SF1010 Shape-Flex interfacing for a small pouch. It was just the I needed and was quick to pick up (vs finding the right bolt, bringing it to the counter get cut, etc.).

Why Is Interfacing Important?

Interfacing holds the structure of your sewing project.

This helpful material is not only used to keep the structure of garments. It’s crucial for a professional look in handbags and purses. Interfacing is the difference between a sturdy tote bag that holds itself up without support, and a lifeless, limp tote bag that flops over immediately after putting down. In other words…

Interfacing is the key to making projects look impressively handmade vs. “charmingly” homemade.

If you are working on a project that requires interfacing, don’t skimp on this part to save time and money. The look of your project will suffer for it. Take a little time to understand the different types of interfacing and then jump in – you won’t regret it!

Categories of Interfacing

Interfacing has a few main categories to choose from. Peruse the options below and then we’ll go over how to choose between them.

What is Interfacing in Sewing: Fusible vs. Sew-in

The two main types of interfacing are fusible and sew-in.

Fusible interfacing has a side with a layer glue. When heat activated by an iron, it will literally fuse to your main fabric, immediately giving it more body and stiffness. It’s incredibly easy to use, stays in place and and works on most fabrics. It has easily become the go-to option for interfacing thanks to the convenience and ease of it.

Sew-in interfacing is exactly what it sounds like. You apply it by sewing it onto the garment.

What is Interfacing in Sewing: Weights

In general, interfacing is described as light, medium or heavy weight.

Light weight interfacing provides a little extra body for your fabric. It adds some structure but the fabric will still be flexible.

Medium interfacing is sill flexible but provides more body. One step up from the lightweight options.

Heavy interfacing typically stiffens your fabric considerably.

When choosing an interfacing, make sure to “match” the weights. For instance, when you are working with a light weight fabric, choose a light weight interfacing option. For heavy weight fabrics, choose a heavier interfacing.

What is Interfacing in Sewing: Weaves

Interfacing typically falls into three different kinds of weaves: knit, woven and nonwoven.

What is Knitted Sewing Interfacing?

Knitted interfacing is made of nylon tricot. Not surprisingly, knit interacting is great to use with knit fabrics because it also has the stretchy quality of the main fabric and will therefore preserve the stretch when adhered to your project material.

How to use knitted interfacing: When you lay out your pieces, make sure the stretch goes in the same direction as the main fabric you plan to use.

What is Non-woven Sewing Interfacing?

Nonwoven interfacing is made from fibers that are bonded together to form a fabric. It does not have a grain at all. Nonwoven interfacing has little shrinkage (if any) and it doesn’t ravel. It can be washed or dry cleaned which makes it especially convenient. Sounds good right?

Think of nonwoven interfacing as your all-purpose interfacing. Since it can be cut in any direction and laid out in any direction (no need to match up the direction of the stretch or the grain line), it is the most economical option. Use nonwoven interfacing on any woven fabric (except sheer materials like silks).

How to use nonwoven interfacing: Lay your pieces in any direction with your main fabric.

What is Woven Sewing Interfacing ?

Many interfacing are loosely woven fabrics with a layer of chemical additive or starch to add stiffness. Most are cotton or cotton-polyester blends.

How to use woven interfacing: Woven interfacing has a lengthwise and crosswise grain and must be cut in the same direction as your fabric. Lay out your pieces along the same grainline  as your main fabric. If your fabric is cut on the grainline going lengthwise, make sure to cut the interfacing along the lengthwise grainline too.

Shopping for Sewing Interfacing (Without Getting Overwhelmed)

The first time I went to a local store to buy interfacing I was immediate overwhelmed and intimidated. The aisle was lined with countless options on bolts that all seemed to look the same.

I found a rack of pre-packaged interfacing options which made it really easy to simply find the one suggested in my pattern. I grabbed a couple and went straight to the cashier – completely bypassing the need to choose a bolt and wait on line to have it cut (and engage with a salesperson which would inevitably lead to me revealing how confused I was).

Luckily, the next project I started required another trip to the interfacing aisle and gave me the push I needed to figure things out!

How to Choose the Right Interfacing

Since interfacing shapes and supports your makes, whether it’s a collar of a shirt or an entire handbag, choosing the right one is an important step in sewing your project. 

Here are some tips to help you.

1. If you are using a pattern, choose the option that is listed.
2. No pattern? No problem. First choose between fusible or sew-in.

Fusibles have an adhesive side (sometimes on both sides!)  that is activated by your iron. Note, handheld steamers will not work for fusibles. Sew-in interfacing works exactly as it sounds. You sew it into your project. 

Fusibles save a lot of time as they are easy to work with and are compatible with most materials. They add a crisp quality to fabrics as compared to the sew-in option.

Fusibles are meant to be permanent so if you don’t want it there for good, consider using a sew-in option.

For the easiest, economical option, if you can choose a fusible, go for it. At least when starting out. It keeps things simple.

3) Choose woven, nonwoven, knit (or foam) depending on the project and fabric you are using the interfacing for.

4) Choose light, medium or heavy weight based on the weight of your main fabric. Remember, if you are working with light weight fabric, choose a light weight interfacing option. Heavy weight fabric gets heavier interfacing.

How to Buy Interfacing

Once you know what kind of interfacing you want to use, it’s time to go get it!

Online stores and local shops often offer interfacing by the package or by the bolt. If your choice of interfacing is available pre-packaged in the quanity you need – you are in luck! Simply find the aisle or rack with the pre-packaged options, make your selection and head out! Many projects call for Pellon SF101 (also called Shape Flex). So, you can usually find it in prepackaged bags a the store along with other popular interfacing options.

If you prefer to purchase off of a bolt, you can usually find what you are looking for by skimming the color codes (see below) on the labels of bolts. The label will have the name of the interfacing, the number ID, a description of the product, the fabric materials (cotton or whatnot) and care instructions.

If you are purchasing by the yard, inside the bolt you’ll find tissue paper with the name of your interfacing along with care instructions for it.

Hang on to the tissue and clip it to any left over interfacing material you may have. This will make it easier to identify later on.

Interfacing Color Codes

Many interfacing for sewing brands use color codes to make it easy to find what you are looking for. Here is cheat sheet of two popular brands for your quick reference

Popular Interfacing Brands Cheat Sheet

Most interfacing companies provide similar options but they have different names from brand to brand. Here is a quick reference you can use if you need an alternative based on availability.

Interfacing FAQs

What are Fusible Webs and Adhesives?

Fusible Webs refer to a product that is made of a fiber that melts when heated. When it is sandwiched (and melted) between two pieces of fabric, it will fuse the two fabrics together.

Adhesives cover a range of products that stick on to a fabric one way or another. They can be used to close seams, to mend holes, to add a finish to or fuse things together.

My current favorite example of an Adhesive is Pellon’s Vinyl Fuse. Iron-on vinyl adds a clear, protective layer to fabrics. Most interfacing is fused to the wrong side of the fabric. However, this product is fused to the right side so it provides a cosmetic embellishment in addition to extra support. It gives your fabric the look of vinyl and adds a water repellent and UV rated upgrade.

What is fusible interfacing for sewing?

Fusible interfacing is a fabric layer that is added to sewing projects to provide structure, stiffness or support and has a side with a layer of glue. When it is heat activated by an iron, it will fuse to your fabric, immediately giving it more body and sturdiness.

It’s easy to use, stays in place and and works on most fabrics. It has easily become the go-to option for interfacing thanks to the convenience and ease of it.

The Finishing Touch

I hope this answers your questions about what is interfacing for sewing and why it’s a game changer for your projects.

Of all the helpful tools in your sewing kit, interfacing should be a favorite. It takes your projects to the next level with that professional finish. If you are new to using interfacing for sewing, give a fusible interfacing option a try and check out the difference it makes for your next project. We’re confident you won’t be disappointed.

Happy sewing!