What is Seam Allowance?
Seam allowance is the area between the raw edge of the fabric and the stitching/seam line. In other words, seam allowance is a space from the edge of the garment panel to the seam itself.
If you are a beginner sewer choosing the right interfacing can be a bit tricky at first. There are many types of interfacing and not all of them can be used for the same sewing project. When interfacing is chosen incorrectly it can determine not only the visual outcome of the garment but its durability as well. But don't worry too much! You can use this guide to help you navigate through the complex variety of interfacing.
So let's start from the beginning!
The first question before learning everything there is to learn about interfacing you need to ask is - what is interfacing?
Interfacing is a type of textile that is used to reinforce, stiffen, strengthen, or prevent a garment from losing shape. It is used on the wrong side of the fabric or in between two pieces of fabric, thus making it an invisible component of the garment.
Interfacing comes in different types of material, weights, thicknesses, and colors. It is usually sold by the meter like regular fabrics in a fabric store. Most commonly comes in white, grey, or black color. Different types of interfacing also require different types of application methods. Some of the interfacings require to be sewed in, some of them have a heat-activated adhesive side and require to be ironed onto the wrong side of the fabric.
Interfacing has many uses. Whether you are making tailored jackets or a handbag - interfacing can be an irreplaceable part of the project. Let's look at the most common uses.
When sewing it is most commonly used to reinforce and give shape to collars, lapels, plackets, and cuffs. It makes a collar, lapel, or cuff stiffer, more constructive, and helps to hold the shape of these garment parts. It can be applied to stiffen the fabric which is very thin or lightweight, as well as strengthen it where the buttons or buttonholes require to be added.
For example, if you have a shirt made of linen fabric when adding interfacing to its cuffs you prevent buttonholes from being torn from multiple times of use. Overall, if your garment needs to have ‘’more shape’’ or needs more strength for durability - you need interfacing.
Interfacing helps to support and keep the shape of the purse. Without it, most bags would lose shape way much faster than they do. And although most bags are made from heavyweight, sturdy materials, interfacing is silent support that helps them keep that sturdiness over time.
Interfacing plays a big role in the overall outcome, by reinforcing the fabric and providing stability when embroidering. Embroidering without the interfacing can be a tricky deal - the fabric can get puckered, ‘’eaten by the stitching’’, distorted, or even get holes from the needle.
It is almost impossible to get quality results when embroidering without interfacing. Particularly knit fabrics are extra needy when it comes to embroidery, they can’t be machine embroidered without using interfacing to stabilize the stretchy material.
Gives the quilt extra weight and structure. It can even help to keep the fabric pieces in place while sewing, thus adding precision and a neat look to the finished quilt.
Interfacing is categorized into three types:
This interfacing looks the same as woven fabric, it is not very stretchy and the grain direction must be taken into account when cutting.
Non-woven interfacing is made out of bonded or felted fibers, and either looks like paper or felt fabric. Both of these kinds can be cut in any direction because they have no grainline. Non woven interfacing does not fray or unravel and it is the least stretchy of all the possible types of interfacings.
Knit interfacing is stretchy, flexible, and most commonly used with knit fabrics. Why? Knit fabric is stretchy, therefore it needs a stretchy companion. It helps to prevent seams from breaking and to reinforce while keeping all the knit fabric characteristics.
All types of interfacing (woven, non-woven, and knit) can be fusible, non-fusible, and double-sided fusible. They mostly come in monochrome colors (white, gray, and black).
There are few types of interfacing application methods.
This type of interfacing is applied to the wrong side of the fabric by applying heat. In other words, the adhesive side of interfacing sticks to the wrong side of the fabric when you use a hot iron, thus forming a thicker, stronger, more durable fabric. Fusible interfacing can be knit, woven, and non woven.
Non-fusible interfacing is also sometimes called sew-in interfacing does not have an adhesive side and requires to be sewed onto original fabric from the wrong side. This type of interfacing is great when your sewing project needs body, fullness, and shape, but you don’t want the original fabric to lose its properties and feel.
It is also a preferred option when working with heat-sensitive, textured, napped, pleated, or loosely woven/knitted fabrics. Non-fusible interfacing takes longer to be applied because you have to sew it in, but it has a bigger variety of uses than fusible interfacing. You also need to know a couple of hand sewing techniques for applying this type of interfacing. Non fusible interfacing can be woven, non-woven, and sometimes knit.
Double-sided fusible interfacing has two adhesive sides, mostly is non-woven, and works very well when you need two fabric pieces to be attached to each other and then sewn together. A perfect example of double-sided fusible interfacing would be when sewing appliques. It is placed in between fabric and applique, all layers are ironed making them stick to each other and then stitched together. It can also be used in cap, hat, and bag making.
Choosing the right type of interfacing is essential to your project. When chosen incorrectly it can ruin the whole garment - it can stretch out, be too stiff or shrink after washing, thus making the garment look or feel not the way it was intended.
The key aspect, when choosing the right interfacing is what kind of item are you making and what are the properties of that item. Here are a few rules to guide you when choosing interfacing.
Is it a garment, bag, or embroidery? All of these items require slightly different options of interfacing. For dressmaking - choose woven with woven fabrics, and knit interfacing with knit fabrics. For embroidery choose non-woven paper tear-away interfacing or non-woven interfacing which excess you can cut away after the embroidery is finished. Making a bag? Use sturdy woven or fleece interfacing to support the shape of the bag.
If the garment is woven, then woven or non-woven interfacing can be used. If the garment is knit and needs to stretch, then knit interfacing is required. Make a garment out of jersey fabric? Use fusible tricot. It is quite an important part - the interfacing has to match the flexibility of the fabric. If chosen incorrectly it will break on the seams, give a lot of discomfort while moving, or won't give enough support for the fabric.
The weight (or the thickness) of the interfacing has to fit the outer fabric. The best way to be sure what kind of interfacing is suitable for your sewing project is to make a small test before sewing. This way you will be sure whether the fabric and interfacing go well together.
Only one rule applies when choosing the weight of the interfacing. Interfacing has to be lighter than the fabric from which the garment is being made. So if you are using a lightweight fabric you will need to use extra light interfacing.
There are different weights of interfacing:
Lightweight interfacing is used to reinforce delicate and fine fabrics. This type of interfacing can also be called featherweight interfacing. Its main purpose is to add strength to delicate fabrics.
Medium weight interfacing is the most common in everyday sewing and can be used with most fabrics.
Heavyweight interfacing is used in bags, hats, and other accessories making. You can find it in the brims of the hats, or used to stabilize bags, purses, clutches.
There are a few important steps required when working with interfacing.
Are you sewing an item from knit or woven fabric? Knit fabric always goes with knit interfacing, and woven fabric goes with woven interfacing. However, if you have woven fabric and a leftover of knit interfacing fabric, that is no problem.
Why is that? Knit fabric needs stretchy interfacing so they could stretch together, but woven fabric only needs other properties that adding interfacing gives to a garment. In other words, the stretch fabric can only go with stretchy interfacing, but non-stretchy fabric can go with both. If you use knit interfacing with woven fabric, it won’t give you a very sturdy effect but will give your fabric extra thickness. So if that suits your sewing project - go for it!
Most interfacing types can be found in the monochrome color range - white, grey (charcoal), and black. When you are sewing white/light colors use white interfacing, for dark garments use black or dark grey. For mid-range colors, the best way to pick interfacing is to make a test.
To find the right color hold a piece together of your fabric to see if the interfacing does not shine through. Sometimes if you are sewing sheer, see-through, or loosely woven/knitted fabrics you will need to improvise and use other fabrics instead of interfacing. For example, if you are sewing a garment from sheer fabric you can use matching color organza fabric instead of interfacing.
Prewashing and preshrinking is great step to avoid deformation of your garment after washing. It can also prevent bubbles that appear on your garment when fusible interfacing starts to shrink after the first wash.
How to prewash your interfacing? In most fabric shops you can ask for instructions when buying your interfacing, or you will find these on the package of your interfacing. Some interfacing fabrics even come with labels that say ‘’no pre-shrinkage required’’.
But if you don’t cant find any instructions for preshrinking your interfacings use these guides:
For sew-in non-fusible interfacings (washable type) - use a washing machine and tumble dry or line-dry them.
For sew-in non-fusible that are used in garment tailoring (dry-clean-only type) - use a garment steamer or dry iron press a damp cloth all over it.
For fusible interfacings - fold the interfacing and dip it into hot weather, leave it there to cool off, use a towel to remove excess water, and hang to dry.
Not to ruin an interfacing fabric that has no preshrinking instructions, always make a test wash with a tiny piece of it. Measure it before and afterward for excessive shrinkage, look for high distortion, creases, and excessive bubbling. If the test swatch does not look too bad, proceed with the whole amount of fabric.
You can always preshrink the interfacing once you buy it and have ready-to-use interfacing once you need it.
If you are unsure whether the interfacing you picked will match the outer fabric make a test swatch. Try to apply it with heat or sew it in, wash it if needed, try to treat this swatch the way the finished garment will be treated and if the outcome is the way you expected it, use it on your original project.
Cut out the panels the same way you cut your exterior fabric - make sure to mind the grain direction and mind seam allowance. You can trim seam allowance later if you need that to avoid bulky seams or you can cut it out with a smaller seam allowance from the beginning.
If you are using fusible interfacing it is important to know that it has to be cut before it is fused. Don’t try to fuse the entire yardage of interfacing on your fabric because it is impossible to match the grain directions.
When you have matched the type, color, pretreated, and made a test with your interfacing - sew it in or apply it with heat.
Interfacing sewing is pretty easy - match the grain direction, use a tailor’s tack stitch to attach it to the main fabric, trim the seam allowance if you don’t want it to be bulky, and sew everything together.
When you apply heat make sure you know what are the instructions for the temperature. Some interfacings are made out of heat-sensitive fabric like nylon and can melt at higher temperatures.
In some cases, you are using non-fusible interfacing, but you would like it to be fused together with your fabric. There are a couple of options to be used when you need two layers of material to stick together.
Adhesive sprays are also called spray adhesives. These are sprayed in between two fabrics to make them stick to each other.
Fusible web is a material made out of heat-activated glue that melts in between two layers of fabric making them stick to each other.
Both of these options can be slightly tricky to work with, therefore a test swatch is always recommended.
Working with interfacing can be tricky sometimes. One of the most common mistakes is using iron on the wrong side of interfacing.
Fusible interfacing has two sides - one with glue dots that are meant to stick to the wrong side of the fabric when heat is applied and an outer side that has no glue. When you apply interfacing you have to place the wrong side of the fabric facing the glue containing the side of interfacing and then press them together using a hot iron. However, sometimes it is hard to spot the glue dots and the sides get mixed up. When you mix up the sides and press your hot iron against the side that contains the glue your iron will be left with a dark sticky residue that is hard to clean. If you are faced with this issue simply use a wet dryer sheet or a cloth soaked in water mixed up with liquid dish detergent or vinegar to scrub your cooled-off iron.
Sometimes interfacing is not the right option for your sewing project because it does not have the properties you want. Or adding shape and strength for some parts (lapels, plackets, cuffs, and collars) of your project it’s not enough. In these cases, you can use other options that can add desired properties to your sewing project.
Quilt batting, sometimes also called quilt wadding, is a type of insulation used in quilt projects such as blankets, pillows, bags, etc. Batting is placed in between two layers of fabric to provide extra warmth, heaviness, dimension, and texture. Batting or wadding can be made out of all kinds of fibers - wool, cotton, bamboo, or polyester. Weight and thickness of batting are measured by lofts - fewer lofts mean it will be thinner and more lightweight, more lofts mean extra thickness and weight. Batting or wadding usually comes in white and off-white colors.
You can use batting instead of interfacing when you need the item not only to have a more constructive shape but when you need extra heaviness and warmth. You can also use multiple layers of batting if you need extra dimension added to your sewing project.
By definition clothing insulation is a layer of fabric or fibers in a garment that protects against cold or heat. Insulation comes in various types and can be made from all kinds of fibers like cotton, wool, fur, duck down, polyester, and mixes of synthetic and natural fibers.
Sewing foam is a thick dense sponge-like material that is used to add bulkiness, thickness, and sturdiness to your sewing project. Thin types of foam are mainly used in bag or wallet making, and thick types of foam are used in cushion, upholstery, or mattress making. The foam used in sewing can be fusible and non-fusible.
Sewing with foam can be a tricky deal and leave you with unwanted bulky seams. One of the main sewing tips when working with foam is to trim the seam allowance. Always make sure that the piece of foam placed in between fabric has a smaller seam allowance than the inner and outer fabrics.
Fusible fleece is a soft stabilizing fabric that comes in different weights, thicknesses, and single or double-sided fusible. The texture of the fabric reminds a compressed and flattened plush material. This material is usually used between two layers of fabric and serves great when you need to add extra body, fullness, and softness to your sewing project. Advice if you are working with bags, consider non-fusible fleece because the fusible type can leave you with unwanted wrinkles on your bag.
Fusible web is a non-woven material made out of heat-activated glue that melts and makes two layers of fabric stick together. It is great when sewing on appliques or in quilting projects. Working with a fusible web sometimes can be slightly tricky and there are a few things to keep in mind. When you use iron - press it, do not go back and forth. This way you won’t end up with distorted fabric and unwanted wrinkles. Another thing to keep in mind is the temperature - make sure not to overheat it or else it can become too stiff.
Using fabric instead of interfacing sometimes can be your only option to achieve the intended outcome. For example, when working with sheer fabrics you can use other stiffer sheer fabrics like organza as interfacing for cuffs, collars, or plackets. Other fabrics can not only add additional properties like stiffness, structure, texture but can also add a visual effect like color or print that shines through the outer fabric. You can get beautiful and unexpected outcomes when experimenting with fabrics to be used as interfacing.
The lining is used as an inner layer in a garment, hat, or bag making to provide stability, finished look, or warmth. Lining can be made out of fabric or even fur. It is not only a functional part of the design but also a visual part. In most cases, the style and color of a lining are selected to match the overall look and idea of the garment. Some of the garments have a partial lining and some even have a removable lining that is attached to an outer shell of a garment with buttons, snap fasteners, or zippers.
Generally, interfacing, underlining, and interfacing are all used to give the garment’s fabric properties that it doesn’t have. All of these terms refer to a layer placed under the exterior fabric or in between the exterior fabric and the lining. Most of the materials that can be used as interfacing can also be used as underlining or interlining.
One garment can also have all three - it can have parts containing interfacing, and parts with underlining and interlining. The difference between interfacing, underlining, and interlining is mainly why it is used and where it is used. So what is the difference between these uses?
In garment sewing interfacing is mainly defined by the location or where it is used. Mostly it is a part of shirt collars, jacket lapels, plackets, cuffs, buttonholes and similar places. It is also used in hat and bag making.
Underlining is defined by the way it is used and also where it is used. It is mostly a part of the bodice and sleeves. It serves as a support for the main fabric. It gives structure, prevents garments from losing shape or growing. Sometimes the exterior of your garment contains two types of fabric with different properties. In this case, you can equalize the properties of both fabric types by adding one type of interlining to one and another to the second one.
Interlining is an additional layer mainly used to add warmth to the garment. In most cases, it is a part of the bodice construction. Because it adds bulkiness you can rarely find it in sleeves or other parts of the garment.
Seam allowance is the area between the raw edge of the fabric and the stitching/seam line. In other words, seam allowance is a space from the edge of the garment panel to the seam itself.
Interfacing is a type of textile that is used to reinforce, stiffen, strengthen, or prevent a garment from losing shape. It is used on the wrong side of a fabric or in between two pieces of fabric, thus making it an invisible component of the garment.