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065: Hemming Stretchy Fabrics - My Top Tips

with your host, Jacqui Blakemore

In this article

What makes hemming stretch fabrics a challenge?

I love garments made from stretchy fabrics, but one thing I used to dread was hemming them.

Woman frustrated about hemming stretchy fabrics
Hemming knits can be frustrating

The hems always seemed to pucker or stretch out and I just found it so frustrating until I learned a few tips and techniques to get really great results every time. So in this blog post I'm going to share some different methods to hem your knits and some tips to avoid the common problems that you might have encountered.


When I first started making clothes with stretch fabrics, I found that I had problems with the hems stretching out or going wavy, or if I was wearing them, then the stitches might pop or come undone.


I thought I wasn't very good at sewing until I found out that there were a few techniques and tools that you can use to get great looking hems consistently, so I want to share those with you today.


So I was thrilled when I made my first t-shirt. I don't know whether you remember making your first stretch garment. I've mentioned in previous posts I found it frustrating to buy t-shirts in the shops. So when I was able to make my first t-shirt, I was delighted.


My overlocker mistake

But at the time, I didn't have an overlocker, and I just used my zigzag stitch to sew the hem. And whilst it looked okay, I really wanted it to look as professional as the ones bought in the shops.

Using overlockers with stretchy fabrics
My overlocker mistake

So I invested in my overlocker because I thought that I'd be able to use that to sew everything for my t-shirt.


What I didn't realise was, at the time, that although my overlocker is amazing and I do love it to bits, it's not the right machine for hemming knits. But it did help me to get a great finish on the seams, and for constructing my stretch clothes.


So I realised that I had to do a bit more learning, and through lots of trial and error, I found a few methods that I now love. So I wanted to share those with you, together with some things that I've tried that haven't been quite so successful, so that you can avoid those.


Common problems when hemming stretchy fabrics

So what things can go wrong when you're hemming your knit fabrics? Well, there are five common things that I think I've experienced and you may have done too.


1 - Uneven Hems

So the first is uneven hems. When you work with some knit fabrics, such as jersey, you can find that they roll up at the edge, and this can make them tricky to work with, especially when trying to get your hems even.


2 - Puckering

I've also found that sometimes I can get puckering along the hem. I've found that with some lightweight knit fabrics in particular, the hem can sometimes get all gathered up as I'm trying to sew it.


3 - Wavy or stretched out hems

I found in the opposite direction that sometimes they stretch out or it goes wavy. So if the fabric has a high amount of stretch, then I've found that it can stretch out as I'm trying to sew it, and that can make the hem look wavy.


4 - Thread breaking & skipped stitches

I've struggled fairly recently actually with thread breakages and skipped stitches. So with working with fabrics with high elastane content or more densely knit fabrics, then I have experienced problems with thread breaking as I try to sew the hems and other seams.

I've also had problems where stitches have skipped, like it hasn't managed to catch the bobbin thread to complete the stitch each time.


5 - Popped stitches & hems coming undone

And finally, one of the other problems I've had is when I'm wearing the garment, sometimes the stitches pop. So as you go to stretch the garment, the thread breaks that happens particularly on close fitting garments. As I put them on or take them off and had to stretch it out.


So it's easy to see why hemming knits can be challenging, right? And if you've had these problems, then you're definitely not alone.


These are all things that I have and sometimes still do experience, but there are ways to resolve these issues. But let's start with the techniques that you can use, and then I'll share with you some key items of equipment and some tips that can make your life easier when trying them.


Characteristics of stretchy fabric hems

I should say at this point that most knit or stretch fabrics don't fray.


So with woven fabrics we often fold the hem over twice so that the fabric edge that might fray is hidden inside the hem. With stretch fabrics you don't need to do that, you can just turn them up once.


This is good news as some of them, particularly those that are prone to curling or rolling, are tricky enough to work with at the best of times.

Jersey dress with long hem
Not all jersey hems need to stretch

The other thing to consider before deciding on how you'll finish your hem is whether your hem actually needs to stretch out or not.


If you're making a fairly close fitting garment and will need to stretch the hem when you put it on or take it off, then one of the following techniques will allow you to do that without the thread breaking and having to redo the hem all the time.


If you're making something like a dress or a skirt with a wide hem that won't stretch when you put it on or when you're wearing it, then it can be easier to just use a straight stitch with a slightly longer stitch length - 3 or 3.5 to make it a bit more decorative.


And also think about the durability you'll need for this garment. Will it be a high wash and wear? Is it going to get a lot of rough and tumble like children's clothes? Or is it a more dressy garment?


These might factor into your choices of technique to suit the garment that you're making.


Hemming Techniques

So I'm just gonna tell you about a few of the techniques that I've tried.


Zigzag stitch hems

So the first is, as I've mentioned, the zigzag stitch. This is one of the first options I used when I was making stretch garments and that was just to turn up the hem allowance and stitch it in place with a zigzag stitch.


Using the zigzag stitch allows the seam to stretch without breaking although if you make the stitch width and the stitch length too small it will limit the amount of stretch.


Just a reminder that the stitch width is how far the needle travels from side to side. Usually indicated by a zigzag icon on your sewing machine.


The wider the stitch, the more stretch it will have, but also the more noticeable it will be on your garment. The stitch length is the amount that the machine moves the garment between stitches. This is usually indicated by a dashed line on your sewing machine. The longer the length, the looser the seam will be, but the more stretch it will have.


For hems that need to stretch I tend to use a width of around 2 and a length of 2. 5, but I do vary it depending on the fabric and my mood at the time.


Test out different options on scraps of fabric and see which one you like the best. It's worth testing it on two layers of fabric so that you can open it out and see whether the seam opens out too much as well.


You could also substitute the zigzag stitch with another decorative stitch from your machine, if you have them. Look for stitches that have some width to them and test them out on your scrap of fabric first.


One thing to be aware of though is that the more times the needle has to go into the fabric or it has to be moved back and forth, the more likely it will be to stretch it out.


Pros and cons of zigzag hems

So the pros of using the zigzag stitch method are that it's the easiest method because it can be done on your sewing machine and you can sew the hem from the wrong side making it easier to see so you can get it a consistent distance from the edge of your garment.


But the disadvantages or the cons of this method are that when you use it on some fabrics, particularly lighter weights, it can go wavy or pucker. But I am going to cover some items in the equipment section to help with that.


Because the edge of the fabric isn't finished, I don't think this method washes quite as well, especially if your fabric is prone to rolling, so that might be a consideration.


Twin needle hems

The next method is my go to method, and that's to use a twin needle.

Twin needles (various widths)
Twin needles (various widths)

In case you haven't seen one, a twin needle has two needles linked together on a single shaft.


They come in different widths, and there are jersey or ballpoint versions, so it's worth checking them when you buy.


The narrower widths are good for finer fabrics, but you're the designer, so you can choose what width suits your style.

Most modern sewing machines have a wide hole at the foot plate that will work with a twin needle.


Where you usually thread your machine from the top, you'll need two threads. The easiest way to do this is to wind two bobbins with your thread color and place them one on top of the other, where you would normally put your spool of thread.


Some machines have a separate stand that you can use, so if you have the manual for your machine, then that's worth checking out.


You thread both threads through the top of your machine as you would your normal single thread. I tend to do this with them both at the same time.


The needle will fit into your usual needle location. And then you thread each needle with one of the threads. Your bobin underneath is as you would have it for your regular sewing.


When you sew with the twin needle, you get two lines of straight stitches at the top and a zigzag stitch on the bottom. I always test this stitch on a scrap of fabric so that I can make sure everything's coming out okay. And if you're gonna be sewing two layers, then test it with two layers of scrap fabric.


I use a straight stitch and tend to use a slightly longer stitch length (3 or 3.5). One thing to be aware of is when you're using a twin needle is to get the straight stitches on the right side of your fabric you have to sew your hem with the right side on top. So that means that you can't see the edge of your folded under hem underneath because that needs to be against the bed of the machine.


So this is where using your hem guide* or a tape measure and pressing up your hem allowance before sewing can really help. And practicing on scraps to get your eye in before you work on your final garment can also really help.


I've found that I get the best results when I sew with both needles going through the seam allowance of the turned up hem, rather than trying to get one needle either side of the turned up edge.


Sewing machines don't seem to like it when two needles are going through different thicknesses of fabric at the same time.

Overlock the edge for stability
Overlock the edge for stability

I also like to overlock the edge of the fabric before I turn up the seam allowance. This has two benefits. It gives me a nicely finished edge that washes and wears well and it also adds some body to the edge of the fabric.


When I'm sewing, I can then feel for that overlock stitch through my fabric to make sure that it's lined up with my stitch line as I sew.


If you're planning to make more of your own garments, then I'd highly recommend investing in an overlocker , as I think they help your seam allowances live through more washes and wears.


And they're just really helpful when sewing stretchy fabrics. I tend to use a three thread overlock and just my left hand needle in my machine to reduce the amount of thread required. And I don't trim anything off as I'm overlocking, I just neaten the edge of the fabric, if I'm using it just to do a finish, particularly for turning my hems.


Pros and cons of twin needle hems

The pros of a twin needle, are that it creates a similar effect to the one that you get in ready to wear. And if you use the option for the overlocked edge, then it's also really hard to see the zigzag from the wrong side.


The hem stretches with the fabric, and once you've done it a few times, it's a relatively easy method.


Twin needles aren't a big investment and you can make it decorative with different colour threads if you want to make more of a statement.


The cons of the twin needle method are that it can be challenging to work from the right side of the fabric and keep the stitching close to the edge of the turned up hem.


Depending on your fabric it can also create a tunnel effect where the fabric bulges between the two stitch lines but I'll give some tips a bit later on how to minimise or avoid that. The threads can also rub against one another and break, particularly , if you're sewing very long hems.


So good quality threads are best and slow down the speed when you're sewing to try to reduce the friction.


Fabric band hems

The third method I wanted to talk to you about is using a fabric band. So it's not conventionally a hem as such, but it does give you an alternative to sewing a hem if you're feeling you're not getting a very good result that you're not really getting a good result with that. So even if your pattern doesn't include a hem band, you could create your own if you wanted to use this method.

Jumper with fabric band hem
Jumper with fabric band hem

In this case, you create two rectangles of fabric that are the same length as the bottom of your front and back bodice pieces. Decide how deep you want the band to be, for example 2 inches, and then double that to give you the depth of your rectangle.


So in this case, each rectangle would be 4 inches deep, with one the length of the front bodice bottom edge, and one the length of the back bodice bottom edge.


Sew the short ends of the front and back rectangles to one another to create a circle, and then fold the band wrong sides together and stitch the band to the bottom of your garment, either with your zigzag stitch or with your overlocker. And hey presto, no need to worry about hems.


Pros and cons of fabric band hems

The pros of this method are that it's very easy to sew and it gives you consistently neat finishes when you use it.


The cons are that you'll need a bit of extra fabric if your pattern doesn't include this feature. And it doesn't really work for garments that have curved hems or maybe a split at the side.


Coverstitch hems

If you want to get exactly the same effect as you get with ready to wear garments, then you'll need a coverstitch machine.

Coverstitch machine
Coverstich machine

This machine looks a bit like an overlocker as it has between 4 and 6 threads. And there are machines that combine the two functions.


With a pure coverstitch machine, there is no cutting blade, but it allows you to sew straight stitches on the top and creates a similar stitch to an overlocker on the bottom.


Entry level coverstitch machines start at around £600, so they are an investment.


I have mixed feelings about domestic coverstitch machines, as I haven't had a very good experience with mine. I have a Janome Cover Pro 2000 that I bought because I really wanted to hem t-shirts and other garments in a professional way.


It works really well on woven fabrics, but it's quite temperamental on stretch fabrics, which is what I particularly bought it for, especially fine ones. And I struggle with skipped stitches no matter what I've tried. I think it might have just been a Friday afternoon machine but I have read other reviews of other brands and this seems to be a common problem with these types of machine.


Pros and cons of coverstitch hems

But the pros of a coverstitch machine are that when they work they are actually really easy to use and they do give consistent results. They don't suffer from the tunneling that you get with a twin needle and you don't need to overlook the edge of the fabric.


The cons are that they are significant investment and like an overlocker, they do take a bit of getting used to. There is a particular way that you need to remove your project from the machine that took me a bit of trial and error so there is a bit of a learning curve.


Other methods to try

A few other methods that I want to mention that I don't personally use or haven't tried are

  • Sewing a straight stitch with a stretch thread I asked on my Instagram if anyone had tried using stretch thread and the reports back were very positive (see the links section for some options).

  • Machine sewn blind hem, using a blind hem foot I have to be honest and say that I think getting a machine sewn blind hem to work even on woven fabrics is hard enough and I don't think I'd have the patience to do that on a knit. But you could sew a blind hem by hand as well if you didn't want any stitching to show on the right side of your garment.

  • Decorative faux flatlock There's also one method in this blog post for using an overlocker to create a more decorative faux flatlock that creates a long vertical stitch along the hem. (Again, I don't think I'd have the patience to do that!)

Helpful equipment

So now we've talked about a few of the methods, let's go through some of the equipment that can make life a bit easier, and some tips to help you avoid some of the problems that we talked about at the beginning.

1 - Iron and pressing cloth

As with any fabric, a key tool to help with hemming is your iron, and if you have one, a pressing cloth*.

Iron and pressing cloth
Key tools - Iron and pressing cloth

I often use my iron to press up the hem allowance before I pin and sew, particularly on garments with long hems, like dresses or skirts, because it can just be easier to measure and press up the hem allowance on your ironing board as it gives you a nice flat surface to work with.


Your iron is also required for applying some of the hem tapes, and stabilisers.


My tip for using your iron is to make sure that you test it on a scrap of fabric first to make sure that you have the temperature set correctly. Many stretchy fabrics will stand some steam and that can be really helpful when pressing up hem allowances. You can also use a damp cloth or a bit of calico if you don't want to use the steam option.


They can also be ideal after you've sewn your hem to get rid of some of the waviness if you have got some of that coming up. So a bit of steam might just help the fabric return to its original shape.

2 - Tapes, stabilisers and spray starch

I think this was the biggest help for me when I was first learning to sew hems on stretchy fabrics. I was struggling to get my twin needle to give me a good result, and then I found a product called Knit-N-Stable*, which is a stretchy iron on tape that gives a bit more body to the fabric and helps the machine give a bit more consistent tension to the stitches.

This was the first thing that got rid of the tunneling problem for me, and also stopped my hems from stretching out. With this tape, you just iron it on. It's not an adhesive, you just iron it on to give body and stabilise the edge of your fabric.


There are other tapes that people recommended, with the most common one being Heat n Bond's Soft Stretch*, and there is a Lite* version of that tape that is the sewable version.


These are iron on, double sided adhesive tapes, so you can stick the hem in place before you sew it.


You iron the tape on and and then peel off the paper backing, fold your hem up, and then you iron it again to hold the hem and provide stability.


If you use these tapes though, be sure to buy the sewable Lite version. If you use the no-sew version, it can gunk up your machine needle.


You can also use spray starch on the bottom edge of your fabric to give it a bit more stability while you sew it, and then it washes out the first time that you wash it.

It can be really helpful if your fabric's curling a lot and hard to manage. But don't leave it on the fabric for too long, because it can eat away at the fabric a little bit, and by too long, I mean months and months.

3 - Overlocker

So we did touch on it earlier, but your overlocker can help with your hem, not by sewing the hem itself, but if you overlock the edge of your fabric, that also helps to minimize it stretching out and it can give it a bit more body when you're sewing the hem.

4 - Ballpoint or stretch needle

If you're going to use the zigzag or decorative stitch option, then you'll need a ballpoint or stretch needle. Deciphering the names and numbers on needles can be confusing so I put together this quick and easy guide to help you pick the right needle for your project.

If you go down the twin needle route, then you'll need one or more twin needles, depending on the width you want to use for your fabric. If you struggle with tunnelling with your twin needle, try a wider needle.


And you can also try slightly increasing the upper thread tension. This is a dial usually on the front of your machine, near to where the thread goes down towards the needle.


It's usually set to a middle number in the range, something around a 4 or 5, but if you increase it to a 6, it can sometimes help to force the zigzag on the bottom of the fabric to be a bit looser, which in turn stops it bunching up the fabric between the lines of the stitching.


Just remember to set it back when you swap out your twin needle.

5 - Walking foot

So if you have a walking foot for your machine, then it can be really helpful to use it when sewing stretch fabric hems. It can help to reduce the waviness of the hem if you are getting that problem as it stops the fabric from stretching as the machine moves it forward for each stitch.


If you don't have a walking foot then if you have an option to reduce the pressure of your presser foot that can also help. It's usually a knob on the top of your machine but check your sewing machine manual if you have one. Just remember to make a note of the setting before you change it and then to change it back when you go back to sewing your woven fabrics.


6 - Other tools

Other tools we've mentioned include hem guides which come in a variety of shapes and sizes and help you to measure off your hem allowance consistently. I do have one or two different types of those but to be honest I tend to use a tape measure or a small 6 inch ruler that I have.


If you are using a twin needle, I also saw a recommendation to use woolly nylon thread in your bobbin.


I haven't tried this, but others report that this is a bit more stretchy, so it can also prevent the tunnelling that you can get with a twin needle. If you use this, you need to hand wind it onto your bobbin, a bit like you would with shearing elastic.


Avoiding skipped stitches

So one last issue we haven't really addressed was skipped stitches. I think this has been the one I find the most challenging to resolve. But in my experience, this is usually down to the combination of needle size and type and thread thickness that I'm using.

Threads can cause skipped stitches
Threads can cause skipped stitches

I've found that particularly when sewing zigzag on stretchy fabrics, if my needle is too thick for the fabric or my thread is a bit too thick, it just skips all the time.


Good quality threads tend to be a bit finer and a bit less prone to the fluffing up, which means that they go through the needle more smoothly. This gives the machine the best chance to create the stitch.


So I tend to go back to Gutterman's threads and for finer stretch fabrics I try to use a 70/10 needle, either ballpoint or stretch depending on the fabric type.


For more information on sewing machine needles, have a look at this guide to sewing machine needles.

Useful links and resources

Equipment

Blog posts


To listen to the podcast version of this topic click on your favourite podcast app below:

And if you would like more help with any of the aspects mentioned in this article or this podcast episode then I would love to hear from you so do please email me at hello@sewmuchmorefun.co.uk.


Thanks for taking the time to read this article and I hope you find some useful tips that you can apply.

Happy Hemming!


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