Laurens Top Sewing Tips

Guide to Interfacing for dressmaking
Part Five

Blog / 15 March 2019

When making your own clothes it will only be a matter of time before you come across interfacing. It’s a really important part in the construction of certain styles and parts of garments so knowing more about it is a must for dressmaking.

Find out more in my latest Youtube video or read on for notes and tips!

What is interfacing?

It’s a type of fabric that is treated with a stiffener and it is used on the inside of garments to give structure, form and strength to them. For example, the collar and collar stand, a cuff, a waistband, a neckline and button band are all common places that interfacing will be used

Should I use interfacing?

If your pattern calls for it - yes! Without it, garments will stretch and bag out of shape, might look a bit listless and won’t last as long.

There are so many different types of interfacing, it can seem a bit overwhelming, but I’m going to break it down into the common characteristics you’ll need to know to make sure you use the right kind for your project

  • Fusible and non-fusible interfacing
  • Woven and non-woven interfacing
  • The weight of it; light weight, medium weight or firm
  • The colour of it: black/charcoal or white

Fusible and non-fusible interfacing

Fusible interfacing - this type of interfacing is the easiest to use as it comes with a heat activated adhesive on one side. Once the interfacing is heated up with the iron it will permanently stick to the fabric. Pictured right.

Non-fusible or sew-in interfacing - this type of interfacing needs to be sewn onto the main fabric just like another layer of fabric and will be held in place only by stitches. It will can result in the main fabric being less ‘stiff’ while still being supported by the interfacing.

  • You might use it on napped fabrics like velvet or fur as the pressing needed to bond the adhesive of the fusible interfacing could crush the fabric.
  • Certain fabrics can be very heat sensitive, for example sequins, metallics or faux leather fabrics so sew-in interfacing is more suitable for them.
  • If a fabric has a very loose or open weave, such as lace or mesh then sew-in is better as otherwise the adhesive could seep through the fabric.

Woven, non-woven and knit interfacing

Woven interfacing - just like regular woven fabric, this type of interfacing will have a selvedge and therefore a grainline. When you cut it out, you need to make sure that you follow the grainline as you would when cutting out your main fabric. Pictured below left.

Non-woven interfacing - this type of interfacing is made by bonding fibres together, rather than weaving them and therefore has no grainline. It can be cut in any direction and won’t fray so its really economical and easy to use. Pictured below right. 

Knit interfacing - if you are using a knitted or stretchy, jersey fabric and the pattern calls for interfacing then you need to use knit interfacing. It’s a lightweight knitted fabric that can either be fusible or sew in.

Colours of interfacing

The most common colour of interfacing you’ll come across is white but it does also come in black/dark charcoal colour. It’s rare to see any other colours.

It’s best to match the shade of your fabric to the shade of interfacing. If the fabric is a thicker fabric and non-transparent then you could probably get away with either.

If the fabric is lightweight or has a looser weave then its better to match the shade. If you aren’t sure then always do a test patch as fusible interfacing especially can change the overall colour tone of your main fabric

Choosing the weight of your interfacing

The weight or thickness of your interfacing should match your fabric. If in doubt it’s probably better to go with a slightly lighter weight one as a stiffer one will just over dominate the fabric and garment and not look as good.

Lightweight interfacings are better for cotton lawns, viscose, rayon, modal

Below is an example of light weight, non woven, fusible interfacing that I've used in the collar, collar stand, buttons placket and cuff. 

Medium weight interfacings are better for stiffer cottons like poplin or shirting, denim and twills, wools, canvas

Here is an example of where Ive used medium weight, non woven fusible interfacing on the waistband and fly front of a pair of jeans. I also used interfacing on the back pockets and from experience woven interfacing is best for that, especially if you intend to frequently use the pockets (I put my phone in there all the time!). The woven interfacing is much more durable in that context. 

Firm interfacings aren’t commonly used in normal more everyday clothes you might be making as they are very stiff and will give a very dramatic effect to a garment. So it’s unlikely you’ll need them very often.

How to use fusible interfacing

While you are still getting used to interfacing and trying out different kinds, it’s always worth applying interfacing to a scrap of fabric first so you can check that it’s the right thickness and also that your iron is at the correct temperature. For medium weight interfacing I usually use a cotton setting but for lighter weight interfacing I’d use a cooler setting, say wool and then slowly increase the temperature as needed.

  1. Cut out the interfacing to the same shape and size as your main fabric using a pattern piece.
  2. Work out what side has the adhesive on in - take a look at each side and look for the sheen or slightly raised surface. This will be the side with the adhesive
  3. Lay out your main fabric on the ironing board with the wrong side/back of the fabric up. Place the interfacing on top with the adhesive facing down, so that it is in contact with the back of the fabric.
  4. It’s best practise to then place a pressing cloth over the top to protect your iron, you may also want to place a pressing cloth underneath as well to protect your ironing board.
  5. Then hold the iron over the fabric for about 10 seconds. Try to keep the iron still so that the fabric layers don’t move around. Continue pressing with the iron over the whole area in stages as your iron will only cover a certain area at one time.
  6. Once you’ve finished check that the interfacing has bonded. See if you can peel it away or if it’s lifting up off the fabric in any areas and go back over it as necessary. Leave it to cool a little before moving onto the next stage.