How to underline a garment, plus some mistakes to avoid!

Underlining a garment 

Today in honour of the beautiful new Valerie sample from our photoshoot, I am sharing some underlining tips for you! And of course, if you haven't already got the Valerie pattern, get it here today! 

The lovely garment in question which has been underlined!

And of course, the very lovely inside!

What is underlining?

In short, underlining is a layer of fabric underneath your main fabric, that you treat as one with the main. With underlining, you essentially create your own 2-ply fabric. It's different to lining, as lining is like a separate unit that is only attached to the main in a few key areas.

Why underline?

Different reasons for different fabrics

-You may want to underline if your fabric is a loose weave or unstable and you feel it needs the extra support to hold its shape.

-Your fabric may be sheer and you want to it be more opaque.

-You may want to change the properties of the fabric to be stiffer or heavier.

-You may want to add warmth to your fabric by adding a thermal layer!

This fabric was slightly sheer, which meant you could see through the fabric enough that another layer underneath it would show. This fabric was far too beautiful to not give it the finest treatment, so I opted for an underlining. More work, but a lovely result. The tips I will share will be focused on the techniques used for this garment.

If you match the underlining to the fabric, your results will look more subtle on the inside, but luckily, I've used a colour that stands out so you can really see! 

The benefits underlining gave this dress:

Pocket bag

Of course, I needed to keep the lovely slash pockets. But I definitely did not want the pocket bag showing through the skirt as a white blob! Lining behind the pocket could help counteract this, but I decided that for the ultimate, it needed an underlining (which provides a layer BETWEEN the skirt and the pocket) so that the skirt was fully opaque.

Neck facing

The neck facing was the same issue. I did not want a white circle around the neckline!

Darts + seam allowances 

And of course, pressed darts would form a white triangle that could show through to the front of the dress. The same goes for any seam allowances.

Skirt

Underlining the skirt also gave the bonus of modesty (no visible underwear, please).

Can you see why I opted to underline? A lining would have fixed some of these issues, but not all.

You may ask, why did I choose a nude underlining? No real reason other than availability really - I could have gone white but didn't want to brighten the background of the fabric; I wanted to maintain the peachy undertone. So, since I could not find a matching pink, I opted for the nude.

It gives a beautiful body to the garment. When I pick up this dress, it feels so expensive and luxurious. 

What not to underline

Tip: Only underline where necessary - there is no point spending all the time and fabric on underlining places that don't need it.

Also, before you underline, think about whether a lining would serve you just as well. Linings are generally easier as you do not have to attach them all together around the edges.

As you can also see, I only underlined where necessary. The sleeve flounce did not need underlining, in fact, that would have only counteracted the light drape I wanted it to have.

The sleeve flounce is left without underlining.

The pocket facing also did not need underlining, because it is totally hidden behind the underlined skirt piece. Underlining this piece would only add bulk (and waste time and fabric!).

Lifting the pocket up, you can see that the pocket facing has not been underlined.

I also did not underline the neck facings. With the bodice already underlined, they have already been guarded against being seen! Underlining would do nothing here.

 

Underlining basics

Pick a fabric that will give your fabric the right qualities. I made sure to pick a lightweight fabric that would not add bulk and stiffness to my main fabric. See "what to avoid" to make sure you choose and prep your fabric correctly.

You will be cutting double of each piece to be underlined - that is, one out your main fabric, and one out of your underlining fabric.

You will stitch around the edges of the pieces to join your main to your underlining. I do this with a long stitch by machine, within the seam allowance.

Note: when underlining a skirt, check my tip for a slight variation in how you treat your underlining for a better result. (look under "what to avoid, mistake #4" to learn about this extra technique).

Stitch up the centre of each dart before sewing your darts. This stops the layers moving out of place while you fold and stitch! Keep your stitching within the dart; do not go past the tip. I had to be very careful as silk fabrics are very annoyingly good at remembering needle holes, so I didn't want a permanent mark at the top of any of my darts.

 

Once you have secured your underlining to your main in all the key areas, you can just treat them as one going forward! 

What to avoid 

Mistake #1

Don't pick a fabric that will not work well with your main fabric. Imagine how bad it would look to pick a sturdy quilting cotton to underline this garment. It would make it much thicker and stiffer. Think about the properties you want to change or maintain when making your fabric choice.

You can see here that I've used a soft, lightweight underlining that complements the main fabric.

Mistake #2

Avoid shrinkage! If you create a beautifully underlined garment, and then the two layers shrink differently the first time they go through the wash, you could have a real problem on your hands! 

Make sure you pre-wash and give your fabrics a good steamy iron to get any shrinkage out. You're also safer if the two fabrics are the same fibre type so they shrink at the same rate as each other (if they do shrink). 

Mistake #3

Just a quick reminder - Keep your stitches within the seam allowance! Otherwise, you'll have to spend a lot of extra time unpicking those basting stitches. And if your fabric likes to remember holes (like silk), well, those holes will be staying. Plus, if you keep your stitches in the seam allowance, you don't have to spend time taking them out; they can just be left in the garment!

Mistake #4

This is a big one! You really want to avoid creating a situation where the underlining layer is shorter than the main, as that will draw the main up, causing unsightly wrinkles.

I kept my underlining free-hanging on the skirt, and here's why and how!

When the inner layer becomes shorter than the main, it causes an unsightly bunching effect as it pulls the outer layer upwards. It's the same principle as a bubble skirt (where the hem is puffy on purpose), but totally unintentional. What a disaster! 

The longer and more flared the skirt, the more likely this issue is to happen.Think about how the bias stretches differently in all fabrics - you do not want one layer becoming longer than the other! 

The solution is to slightly change the order of sewing so that you can leave the underlining hanging free at the hem. 

Here you can see that the underlining is caught into the side seams and centre back, but hangs freely in between.

Note: For some garments, you don't have to do a free-hanging underlining - generally garments that are not too lightweight, drapey, and don't have anything hanging on the bias will be a lot more co-operative.

Here's my construction order for achieving the free-hanging underlining. It's still joined at the side seams and centre back, but the hem can move freely between those areas.

• Cut the underlining a little shorter than the main (just like you would with a standard lining).
• You will have to hem the underlining separately first, BEFORE you sew the side seams and centre back seams. This is different to the normal way you sew a skirt, where you sew the side seams first and then hem last.
• Finish the edges of the underlining with a zig zag or overlock.
• Finish the edges of the main.
• Stitch within the side seam allowance to join the underlining with the main (repeat at centre back). I actually stepped the edges of the underlining away from the edge of the main by just a tiny bit. This just gives a little more room to the underlining (to further guard against Mistake #2 where the underlining pulls the outer inwards causing bunching, this time across the body). Repeat this for the centre back.
• Sew the side seams and centre back, treating the two layers as one.
• You will hem the main last. Just make sure you keep the underlining hem out of the way while you hem, so it can hang free in between seams!

Final thoughts

Well, I hope these tips really helped you get your head around underlining! It's one of those fabulous techniques that can really take your garment to the next level if done correctly! Please comment with any questions you have, and most of all, happy sewing!