Interlining is a layer of textile placed between other layers of fabric (outer fabric and lining) for added strength, cushioning as well as insulation. Adding interlining can be termed as the hallmark of a high-quality garment. It can enhance the look of the outer fabric to a degree. Interlining gives structure, and depth to the garments, curtains, quilts etc to which it is applied.
It is usually used in garment making, in place of interfacing as usually interfacing is added to selective places only. Interlining can also be added to the whole garment or selective portions. Usually, collars, sleeves, lapels of jackets are given interlining for that padded effect.
When you use interlining with delicate fabrics like soft silk, you give them much-needed strength. If your fabric is soft and flowy but you want a more structured look or you want to make it mold to the body in a form-fitting style, you have no option but to give the fabric some strength and support with a suitable interlining. When linen is underlined it can reduce the characteristic wrinkles.
Interlining fabric – selection criteria
There are some criteria in selecting the best fabric for using as an interlining for your next sewing project
It should not add too much weight or bulk to the fabric
It should have the same care instruction as the outer fabric and lining
It should be cut on the same grainline as the outer fabric and lining
It is not be see-through. You do not want the interlining to be noticeable from the outside.
It should not overwhelm the outer fabric.
It should be insulating enough (if that is the desired effect) without being too thick and stiff.
Best interlining fabrics
When selecting your fabric you have to keep in mind that you will be joining the outer fabric, interlining and the lining and all of these can end up feeling too stiff than what you had in mind.
Decide the type of interlining you want based on the above criteria as well as on the effect you want and how you want to attach it to the fabric. There are flowy interlining as well as stiff interlining. There are interlining that can be attached with heat and also with sewing.
Tricot Knit interlining fabric
This is a special interlining fabric that is specifically used for interlining. It may have small dots on its surface which can be used to attach it to the fabric. You can also buy it without the adhesive dots. This is a very fluid interlining fabric that will not mar the drape of the outer fabric in any way.
This is a very inexpensive option and this material is available in different weights. The one disadvantage is that the material may disintegrate inside the fabric after several washings.
This is a knitted fabric made of acrylic or acrylic wool blend fibers
Polyester wadding is a very inexpensive and very lightweight layer used inside jackets and quilts. Read more about different types of batting/wadding here.
Cotton fabric is used when you want an interlining which is soft enough but stable enough. Commonly used cotton fabrics are cotton batiste and cotton voile – thin enough for good drape. Cotton canvas is used for structured fabrics. Cotton Domette is an inexpensive thick, fluffy and very insulating cotton fabric used inside garments as well as home furnishing as a lightweight and soft interlining.If you look inside some luxurious curtains you will find this fabric inside. Brushed cotton is another such stable, supple and soft cotton fabric.
This is a very fluffy and soft interlining material
Wool can also be used as a very efficient interlining layer. Wool canvas is usually used as interlining in luxury garments like premium quality men’s ties etc.
This is used when you want a stiff durable interlining. Hair canvas would not disintegrate even with repeated washing.
This is a very fluid and lightweight option as an interlining fabric.
This stiff, coarse openweave fabric is great for interlining if you want to give structure and shape to the garment. Usually used inside when making hats.
How to sew interlining
Interlining has to be planned even before the pattern is cut. You have to add enough ease in the garment you plan with interlining to accomodate the extra thickness.
When you cut fabric for the garment, interlining is cut the same as that of the lining and the outer fabric – with the same hem allowances and same seam allowances.
First, the outer fabric and the interlining are cut the same and kept together (interlining is kept on the wrong side of the fabric). Smooth the fabric on a flat surface. Baste along the edges – ie stitch long running stitches along the edges to ensure that they will stay put together. Use a contrasting colored thread to baste the stitch so that you can easily remove the stitches later.
These fabric layers are then treated as one in your sewing. When the lining is added, to the back, this layer will cover the interlining and protect the skin from being irritated.
Another method is to cut the interlining without any seam allowances. It is then hand sewed to the seam allowance of the lining – this sure is time-consuming but this ensures that you do not have too much bulk at the seams.
Some specialty interlining fabrics can be joined with heat application just like interfacing – they will have small adhesive dots.