Friday, May 30, 2008

Underlinings and Interlinings

Underlining / Interlining / Interfacing
Fusible / Sewn-In / Combination

Traditional tailoring is done with traditional materials and sewn-in interfacings. However, in light of today’s improved processes for creating quality fusibles, and in consideration of time and cost, even High end designers are using some fusibles in their Pret-a-Porter jackets and coats now.

What you choose now will, to a great degree, effect the final drape and shaping of your coat. For best results, you should sample Before you start mounting and fusing your fabrics.

Underlining – Body and Sleeves Only
supports the fashion fabric
Underlining is mounted to the fashion fabric prior to sewing, then both fabrics together are treated as one.
Use with Fabrics that need stability:
• Boucle
• Loosely woven tweeds
• Soft animal hair fiber fabrics such as Cashmere and Mohair
• Any fabric that feels fragile,
• And, May be needed for wool flannel if pattern has full heavy skirt (such as V8307 and V8346

Not necessary for most wool flannels that are coating weight, wool tweeds that are tightly woven, and Melton.

Fabrics for Underlinings
• Fine cotton batiste
• Cotton broadcloth or high quality muslin
• Silk broadcloth
• Cotton/silk batiste blend
• China silk
• Cotton flannel – as underlining/interlining (preshrink!)
- Fusible - textured weft insertion products such as Armo-weft, Angel-weft

Interlining – Body and Sleeves Only
Provides added warmth
Interlining is treated the same as underlining, except that it is a layer intended more to add warmth than stability.
If you’re using fabric that requires an underlining, use one that serves both as support and warmth such as cotton flannel, OR use a lining such as flannel back satin that serves the dual purpose. In any event, do not plan to underline, interline, and line.

Fabrics for interlining
• Cotton flannel
• Lambswool interlining – soft as a cloud, expensive and difficult to find
• Lightweight Thinsulate TM

Source list:
See links on sidebar for
Farmhouse Fabrics - batiste and broadcloth
Vogue Fabrics - cotton flannel in many colors
MacPhee - Thinsulate

leave your suggestions for sources in the comments, and I'll add links


Meg said...

Anybody besides me using bouclé? I don't want to hog the blog by asking questions that are only specific to me.

But Marji, just to be sure I understand this post, for bouclé I would NOT underline with fusible AND interline with cotton flannel? I'd pick one or the other? If that's correct, which would you advise I use, flannel or fusible? I have both.

Nancy K said...

Greenberg and Hammer has lambswool interlining. Delicious and expensive.

Kathleen Fasanella said...

Boy, don't want to get cross ways this early in the game but I've learned exactly the opposite (interlining and underling). It was posted to my blog and seemed to be the consensus, at least in RTW. Basically, it boils down to process vs product. Interlining is a product and underlining is a process.

excerpt (from
For manufacturers, interlining is a product, not a process. I was pleasantly surprised to see this definition on the web. Usually urban myth triumphs. The interlining (just like interfacing only a bit thicker) is attached to the shell and after it's been fused or interfaced, it is treated as one layer with the shell. There's no trick or debate to handling it. One caveat, the English (and others besotten with bespoke) will use interlining to mean interfacing (as Dos Fashionistas mentions too) so be wary of the provenance or the context of what you're reading.

Underlining is not the same thing as interlining; Alison correctly described:

Interlining goes between the lining and the fashion fabric, often flannel or quilting to add warmth. Underlining is cut and sewn as one with the fashion fabric, usually to add body.

Interlining is usually used to make something warmer (coats) or insulating (as in the case of drapery). Underlining is a process. Underlining can be any material, even a duplicate of the piece using the same goods. Usually tho, it's a solid colored backing that blends. It's used with diaphanous materials, see-through stuff. Underlining provides modesty and even structural integrity. Typically, underlining is basted or attached in some fashion to the shell piece. The sum is treated as one layer, unlike lining which is treated as it's own layer first, before being bagged to the shell.

As such, I have interlined, underlined and lined all in the same garment :). I don't usually tho. I don't interline and underline the same piece, just one or the other.

Mary OK said...

I am planning a trenchcoat in wool gabardine. I thought I would underline it to add weight. How big a test sample do you recommend?

KayY said...

I am planning to add a chamois piece in the upper back of my winter coat to block the wind. It'll go between the coating and the lining/interlining sandwich. I learned the same terms as Marji - guess they are for the amateurs :)

Marji said...

Ok, Kathleen has it upside down of the way I (and KayY) learned it...linguistically anyway.
For the record, Kenneth King doesn't distinguish at all - uses the terms interlining and underlining interchangeably.

Can we aree that if your fabric needs support you need a layer, either sewn in or fused, that will be mounted to the fashion fabric, and then treated as one with the fashion fabric?

I learned tailoring in the late 1970's from an Eastern European woman who was trained in traditional tailoring in the old country. I still use the language she taught me for the layers.
The language that I'm using is supported in the texts that I've been reading that are meant for the home sewer.
I have the utmost respect for Kathleen, and she does work in the industry. So Kathleen, thank you for sharing the industry language.
So why do you suppose that the differences are there in the language?

Suit Yourself Couture said...

I looked through some of my reference books on this subject out of curiosity:

Reader's Digest Complete Guide to Sewing, page 84, "Underlining gives support...", Interlining provides warmth.".

Couture Sewing Techniques by Claire B Shaeffer, page 212, Backing: Layer of support...called the underlining in home sewing.".

Couture The Art of Fine Sewing by Palmer/Pletsch, page 143, "Underline Large Pouf Sleeves".

Bridal Couture by Susan Khalje, page 57, "The fashion fabric and the underling are joined...treated as a single layer of fabric.".

Singer Tailoring, page 111, "Because the extra layer lies between the lining and the garment, it is called an interlining.",
page 20 "...underling. It lies directly under the garment fabric...".

I usually use silk organza for my underlining. Those new to tailoring will find that you will develop your own style.

Nneka said...

Of the underlinings listed (and including silk organza) does anyone have any thoughts on which are less or more "intrusive" on the original drape of the fashion fabric?

Lisette M said...

G-Street Fabrics, Rockville, MD has cotton flannel.

Kathleen Fasanella said...

Re: existance of language differences.

Why do some people call the evening meal "supper" and some call it "dinner"? It was the varying language differences that inspired the two part series on confusing terminology. There can be differences btwn how home sewers use terms and how we do but that doesn't explain why language practices differ even among people in RTW (and home sewing for that matter).

And how coincidental you learned from an eastern european woman. So did I! Well, he was a man but still from eastern europe, third generation in the tailoring business. His family's factory made suits, sportcoats and coats. Who knows what words they used there, most certainly not english words for underlining or interlining :).

Jenny said...

Am I correct in assuming that whether to interline or not is purely personal preference? I was planning to use thinsulate with my wool flannel to make a winter-worthy coat. Is wool flannel already thick enough without? I guess it's hard to say without feeling it... I think I'll go with the thinsulate.

Thank you again for taking time to answer my amateur questions!

MarilynB said...

Since I have never used thinsulate before, I have a few questions about about it. Is it as thin and soft as flannel, or does it add body? How much warmer is thinsulate compared to flannel? Thanks for any advice.

Nancy K said...

I have used both thinsulate and flannel to interline a coat and I prefer the flannel for drape and ease of use. It also takes up less room especially useful in the sleeves. But that's not to say that you can't use flannel in the sleeves and thinsulate in the body. I live on Long Island, and my latest underlined coat is almost too warm except in the coldest weather, and lately it hasn't been to cold here! If you live in a colder climate, my feeling is that wool flannel isn't warm enough. If you live in a really cold climate, adding a wind shield would help make your coat warmer too. I have never made one, so perhaps someone who has will chime in with instructions and fabrics to use.
I am not interlining my jacket this time, as I want a jacket that is better for the majority of weather here and because it is basically a car coat.