The Complete Handbook of Interfacing

Chapter 1: Understanding Interfacing

Interfacing is the unsung workhorse of the textile industry. It is a layer of fabric, often unseen in the final product, that is applied to the wrong side of your main fabric to provide structure, stability, and shape. Unlike lining, which is a separate garment layer, or interlining, which is used for warmth, interfacing is a part of the garment itself, fused or sewn onto the shell fabric to control its behavior. Without it, a collared shirt would flop, a tailored jacket would lose its lapels, and a waistband would twist and roll. This chapter is about what interfacing actually is, how it physically works within a textile structure, and why the professional demands its precise and correct application.

Let's ground this in a concrete scenario. You are constructing a tailored wool blazer. The fashion fabric, a beautiful Italian wool suiting, has a wonderful drape and a soft hand, but it lacks the rigidity to hold the crisp, sharp shape of a lapel. If you cut the blazer from that fabric alone and put it on a dress form, the lapels will curl, the collar will wrinkle, and the front edges will stretch. This is where interfacing enters the workflow. You will cut a stiff, stable layer of interfacing, often a canvas made from a blend of wool, cotton, and horsehair, in the shape of those lapels and the front of the jacket. You will then secure this interfacing to the inside of the fashion fabric.