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  • Writer's pictureLonda

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!

shrunken interfacing image

Puckers because interfacing has shrunk meaning it was NOT pre-shrunk

Pre-shrinking Interfacings

Sew-In Interfacings – I recommend pre-treating in the same manner in which the garment they become a part of will be washed. Most often, my stash yardage of these interfacings just gets tossed in with the appropriate color load of my regular clothes washing and drying. Press and label and store. If you happen to be considering a stitch-in tailoring interfacing like Hair Canvas, just a good steam would be appropriate. These garments will be dry cleaned anyway. Claire Shaeffer – a very respected authority in garment sewing says: “Generally, I like sew-ins better than fusibles.” 

Fusible Interfacings – It amazes me that many still don’t realize that these interfacings need to be pre-treated as well. The way the HTC educator, Adele Martinek put it in a class was that even though these interfacings “go to H _ _ _ and back” during their manufacture process, the fact that they are then stretched as they are wound onto bolts puts tension back into the yarns that needs a chance to relax before use. I highly recommend following this procedure with all Fusible Interfacings immediately after purchase and BEFORE they enter your sewing notions ‘stash”. Be neat with these instructions, realizing that if you hurry and get a wrinkled mess, you can’t ‘iron’ wrinkles out before cutting with fusibles! ☺

1. Run HOT water into a tub or large basin – make it as hot as possible from the tap. 

2. Loosely fold the interfacing and immerse into this basin of HOT water. Let it remain until the water is cooled off. 

(I’ve forgotten it overnight – and no problem!)

3. Roll interfacing in a towel (beach towel works well) to remove excess moisture, and lay it out to dry. I use my spare guest bedroom bed, or the dining or living room carpet. Beware of household pets clawing on them, however. Note, I said LAY – don’t hang. It is my opinion, that even for stable woven fabrics, the weight of water on the fibers if the interfacing is hung, could cause the fibers to stretch out again. Most often you will find cautions regarding hanging to dry only for knit interfacings. 

Many over the years have called in tears that they put their wet wad of Interfacing into the drier ….. not a good thing to do! Need I say more????

The only additional facts I can add to this topic of preshrinking are the following observations: 

  1. Since you don’t put fusible interfacing in the drier prior to using it in a garment – you must realize that if you do put the finished garment into the drier, you may still get residual shrinkage of the interfacing… = bubbles of the fabric.

  2. Even when an interfacing says preshrinking is not necessary I STILL PRE-SHRINK ANYWAY! Better to be safe than sorry! But I always say – when you sew, YOU are in the ‘Driver’s Seat’ – so YOU do what YOU want to!

  3. Read what Pam posts on her Blog regarding preshrinking of her commercial grade, WIDE interfacings:

“SEW-in or FUSIBLE, Our Interfacings DO NOT SHRINK  because we have the base-fabrics thoroughly steamed before our special resin is applied…so NONE of that annoying and tedious “interfacing-pre-soak/pre-treat nonsense” is needed at all (yay)!”

  1. I do NOT agree that technique of “steam shrinking” by holding the iron above a fusible and giving it a shot of steam to allow it to shrink before applying pressure to fuse it to the fabric is enough to adequately address the possibility of shrinkage. 

  2. Realize that other factors can cause bubbling; not just lack of preshrinking. These include application techniques, and subsequent washing/drying. Don’t blame it all on pre-shrinking. Read on…

Fabrics (including interfacings) can be either

  1. Woven

  2. Nonwoven

  3. Knit

Woven Interfacing is produced by weaving threads at right angles to one another. They don’t stretch in lengthwise (warp) or crosswise (weft) directions. On the bias, they would have stretch, or give and flexibility – which is actually desired in certain areas of garments. 

Pro-Woven Superior Sew-In from Pam Erny’s Fashion Sewing Supply is an example.

Let’s get textile term ‘sophisticated’ here: 

Warp – are the lengthwise threads on a loom – remember by thinking that the lengthwise threads are laid down first – and A comes first in the alphabet!

Weft – are the crosswise threads that are then woven across on a loom – the E comes after the A – get it? 

Nonwoven Interfacing is actually a felting process of fibers – they are ‘stuck’ together, not woven or knitted. Actually think of felt! 

I personally do not recommend Non-wovens as interfacing in garments. Perhaps in crafts and some home decorating sewing they have a place, but NOT in garment sewing. 

Non-Wovens are easily ripper and disintegrate – NOt a good thin!

How can a product that performs like what you see in the above image give stability to a garment over the long haul????  I was taught this by a college professor who had done some research on interfacing in both ready-to-wear and home-made garments and this was her conclusion – with which I heartedly agree.  

Resin Application

This used to be more of an issue in the earlier days of fusibles than I find it to be now, however I want you to realize the different techniques of resin application. I find I don’t like the very regular dot placement method of applying resin as from a roller – last diagram.

resin application methods

The ways the ‘glue’ or resin is applied to fusible interfacing.

Investing just $5 in the ENTIRE 29 page document of Interfacing De-Mystified might just be some of the best project-saving dollars you can invest to add to your sewing knowledge.  Click HERE. to order.  There is a ‘bug’ that seems to keep being hard to find on the part of the webmaster at my website for PDF purchases made with a credit or debit card – meaning that the PDF isn’t always automatically delivered to you.  Be assured, I will see your order and personally see that you get the document download.

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