Interfacing De-Mystified
Interfacing in a garment is like the bones of a garment. Including stabilizing seams as a type of ‘Interfacing’, I will go out on a limb here and state that EVERY well-made garment will have some type of interfacing or stabilizer. What I’m publishing here are ‘snippets’ of the document I wrote which was originally written in 2011 for a class I offered on Pattern Review by the same name. The ENTIRE 29 page document is available at my website as a PDF Product and can be found HERE.
Interfacing comes in 2 varieties: Sew-ins (Stitch-ables) and Fusibles.
What IS Interfacing? Why do we use it?
Interfacing is defined as a 3rd layer of fabric that lays between the facing and outer layer of a garment. Interfacing provides firmness, shape, or ‘body’ to a fabric, and strength and stability to edges. It is meant to add these qualities without adding bulk. Interfacing may also serve to conceal inner construction from showing through to the outside of a garment.
To clarify the difference of similar words:
Interlining is applied to the wrong side of fashion fabric or lining for the purpose of insulating – as in a coat.
Underlining is a separate layer cut with the same pattern pieces, and applied to the wrong side of each piece – then handled as one during the construction process. Underlining serves as a backing for sheer or lightweight fabrics, as a support for unstable fabrics, and even create beautiful seams. Underlining can change the drape of a fabric, and even render it almost wrinkle-resistant. Since we sometimes now use interfacing as an Underlining – this will be covered in this class as well, as it relates to the topic.
Think of a body: Interfacing is the “bones”. It is what gives a garment some structure and endurance. Too often, to march to the “Sew it Tonight…Wear it Tomorrow” drummer… interfacing is completely left out of patterns – even the very best patterns by top designers. In my opinion, this is a mistake. Just because a pattern does not call for interfacing is no reason to omit it. I am responsible for the end product that I am creating – and only I know the specific fabric I am using. Don’t let any pattern dictate your interfacing choices – learn all you can, ask for opinions, test and keep those test samples, and do what YOU feel is correct for your specific situation.
Regarding KNIT GARMENTS – this is an entirely different situation, and though interfacing is often still important, I’ve found that in the relaxed styles of 2015 – that aside from stabilizing shoulder seams and hems, and an occasional jacket collar or facing when more conventional sewing techniques are used, that we see less interfacing in Knits.
Knowledge of interfacing is not only useful as you sew – but as you ‘consume’ ready to wear garments (RTW). I just yesterday opened a Gift Certificate from Lands’ End for a shirt that I returned to them because the collar looked like this:
No amount of pressing or pressing technique could get this collar to look good. The interfacing has shrunk and now there is excess upper collar that can only wrinkle – forever!

Puckers because interfacing