Last year I went out on a wildcamping/bivouac trip in the Alps for the first time in my life. It was an incredible experience, for the both of us actually. We therefore decided to this more regularly this year, the Alps are around the corner anyway. Coincidentally it was also a great holiday option in these strange Covid-19 times, to be able to get away and at the same time keep a distance from people. Nature provides it all!
With the first bivouac we did this year though, I did encounter a few gaps in my gear. One of them was my sleeping bag. My comfortable bag was too bulky and heavy to bring along, and my lightweight mummy bag was not wide enough for my hips. I had to find a quick solution for this problem. Shop bought or handmade, it didn’t matter to me, as long as I could use it this season. Before I jump to the solution I found, let me first jump back a few steps and give you some background.

Car camping vs camping on a hike

We’ve been camping for years and especially the last few years our camping set-up has reached perfection, pretty much. To complete our setup for our car camping trip in the UK last year, we bought very comfortable, breathable and soft sleeping bags. Those are traditional- rectangular ones, that can be attached to each other. They are made out of cotton and made for +10C temperatures. Ideal for the type of camping we normally do. Unfortunately, they are total deadweights when you have to carry your own gear up a mountain. More importantly, those bags are humongous, volume wise and volume is something we don’t have enough of in our backpacks. Especially my pack isn’t big enough to fit all the necessities. I had a choice to make: buy a bigger bag or change some of my gear. I decided to go for the second solution (as I love my bag) and to tackle the sleeping bag problem and find a light weight sleeping bag that could fit my hips. That sounds easier said than done, I promise you!

Mummy shaped sleeping bags

The problem

Now, going back to our pre-super soft and comfortable sleeping bags, we already had lightweight sleeping bags, mummy style. Suitable for +11C temperatures. While Eduard could sleep in his’, for me they were just horrible. I could fit in the bag, but just barely and therefore couldn’t comfortably hold my arms next to my body, or pull up my legs in the bag while sleeping. And therefore I generally used the bag as a blanket, for which it is useless and far too cold. This was already a XL sleeping bag though, so I couldn’t really size up in our local shops.

Male vs female bags

I started investigating plus size options online and quickly found out that my issues weren’t only plus size issues, but also a common problem amongst women in general. Mummy type sleeping bags are made in a way that the widest point is at the shoulders and then it tapers down from there. Which is generally suitable for men, but women also sometimes have wider hips and therefore regular sleeping bags don’t fit properly. There is a plentitude of size- and form-comparison blogs, dedicated to this subject and if you need a new bag and wish to look into bags that are specifically made for women, I strongly recommend you to do your research before buying a generic sleeping bag. For me, buying such an expensive new bag online wasn’t an option I soon realised, so I kept on searching for cheaper and faster options. As we all do, don’t we?

Sleeping bag expander panel

On my search I bumped into sleeping bag expander panels. This extra piece of triangle shaped fabric, along with two zippers, can be zipped onto your normal bag to create a bit of extra girth. It’s incredible to see that for every problem you come up with, somebody already has found a solution. It’s a comfortable thought!
The solution was still an expensive one. For a small piece of fabric, you pay at least twice as much as what you pay for a cheap sleeping bag. Next to that, you also have to make sure that the zipper on the expander fits on your own sleeping bag. Too much hassle for me. These expanders did bring me closer to my own solution by visualising for me what I needed.

The homemade solution

And so I thought: why not use two identical and attachable sleeping bags and cut one up as an expander panel? I could use the two cheap sleeping bags that we had. It was a cheap and fast solution. I discussed this with the owner of that second bag and he agreed with me that it would be a great option. He gladly offered his bag to me. [Probably also because he wants to buy a new mummy bag (in a non-XL size).]

As soon as I got a ‘go’, I pulled the sleeping bags out of storage and laid them on the floor. It took me one day to figure out how I was going to cut the second bag and then it took me one hour to cut and sew the whole bag the next day. Not bad right? Below you can find a quick tutorial on how I did it. Don’t expect too many details, as every bag is different. So you will probably have to tweak your steps to how your zippers (ends) work.


  1. Make sure you have two sleeping bags that can be attached to each other. You can often buy a left and right side sleeping bag of a specific brand.
  2. Decide on which side you want to have your zipper and choose the bag which you want to cut up accordingly. I want to have my zipper on the side of my door of our tent (we have doors on two sides) and so I chose to have the zipper on the left and therefore I cut up the bag on the left. I hope that that’s clear.
  3. Zip them onto each other and lay down in one bag and mark how much space you need of the second bag to lay comfortable in it. Take as little space as you need, as you are still making a lightweight bag. But you want to be able to place your arms next to your body and have a bit of wiggle room (that’s what I wanted at least).
    It’s important to lay down, and not fit the bag as you are standing, as you take in more space while laying down.
  4. As you have marked out on one side where you want to cut the sleeping bag, it’s now time to unzip your bags and zip together the bag that you will cut up. To have a more precise cut and stitch, it’s advisable to clip together the sides next to the zipper, so that the zipper is placed flat towards the surface. This way you will cut the same amount of fabric on both sides. This is the moment that you put away the sleeping bag that you want to keep in one piece. You will only need your expander bag from now on.
  5. Draw out the expander based on your own body shape and try to start and finish as close to the zipper endings as possible. Use the markings you made to create a smooth (rounded) line on where you want to cut the expander. Make sure you understand that you will need some extra space to create a seam allowance (also at the top and bottom of your zippers). I made French seams in this case, that means that I needed quite a bit of extra space as stitched the fabric once on the good side, and once folded over on the inside. I would say that an extra 3cm is good enough. You can draw the line on your sleeping bag with an erasable marker.
  6. Now that you have marked your line, you can cut your expander panel. Take a cup of tea before you do this and make sure you have accounted for all the things you needed to account for. There is no way back from here. When you are done cutting, your fabric should look a bit like the one above. You can already see an expander forming.
  7. It’s time now to move your clips carefully to the other side of the expander. That’s the open side. You can see above how I moved them from the zipper side to the side that I will stitch together. Make sure you have looked inside your expander to see if there are no extra fabrics that are in the way of your expander, like an inside pocket or a zipper protector. I had both and I had to fold them in the right direction before sewing.
  8. It’s time to sew the expander together. I decided to use French seams, as there are many layers inside a sleeping bag. If you don’t know what a French seam is, please do some research, but basically it means that you stitch the expander first on the right side together (with the two insides against each other on the inside). Then you zip the expander open, fold the expander again on the line that you just stitched and stitch the same line over again but this time with the two right sides placed against each other on the inside. [I hope this makes sense for beginner seamsters.] You basically work away the open seam with this method. You then end up with an expander as shown on the left below.
  9. Zip the expander onto the bag as if it is a second adjoining bag. Et voila, you now have a handmade expander for your sleeping bag. All set to go out for a hiking trip!

I hope that this tutorial gave you an idea of what you can do to make your own plus-size light-weight mummy shaped sleeping bag from an existing bag (or two). I recommend you to use old bags if you have them. That makes this a more affordable endeavour. In my case this was worth the money as I think we bought these bags about 8 years ago for a mere 25-30EUR a piece.
If you don’t want to use a second sleeping bag to make this expander panel, you can also buy some zippers and technical fabric to make this happen. I don’t know what would be the more economical option.

And then a last picture to show you what a difference it makes to have a lightweight, small sized bivouac type sleeping bag (left) compared to a ‘normal’ car camping type sleeping bag (right). I didn’t compress them on purpose.
I’m also extremely content that I managed to fit my new, bigger mummy sized bag into the compression bag of the original smaller sized bag.