What Interfacing Does (and Why You Need It)

What is interfacing, and why does everyone use it?

It's the hidden layer that makes your sewing look professional.

If you’ve ever sewn a collar, waistband, or tote bag and wondered why it feels structured — that’s interfacing.

Interfacing is a stabilizing material you add between layers of fabric to give body, shape, and support.
It’s the unsung hero of clean, crisp sewing.

There are two main types: fusible and sew-in.
Fusible interfacing has a heat-activated glue on one side.
You cut it to match your pattern piece, lay it glue-side down on the wrong side of your fabric, and press (not iron!) it in place.
The heat bonds it permanently.

Sew-in interfacing, on the other hand, doesn’t have glue.
You attach it by sewing it into your seams — great for fabrics that can’t handle heat, like silk or wool.

Choosing the right weight is key.
Lightweight interfacing works for collars or pockets on thin fabrics.
Medium or heavy interfacing gives bags or structured garments their stiffness.

And if you’ve ever had a floppy tote bag or a wrinkly collar, chances are you skipped interfacing.

So don’t.
Add that hidden layer, and suddenly your projects will look store-bought instead of handmade.

It’s one of those quiet details that separates “beginner” from “beautiful.”