I did a trial run Bivvy in the back garden last week and had to jack it in due to the cold.
My bag is not up to the current “Season” I know but I found my 3/4 Thermarest inside my Alpkit Hunka made the bivvy bag compress my sleeping bag onto my body – especially my thighs.

So, is there a sub 50cm wide mat I need?
A bigger Hunka?
Do I put my mat under the Hunka(& slide off it)?
Do I use a foam mat.

Your thoughts please.

Oh, yeah…. I could also MTFU I suppose.

Mat under the Hunka? Try some seam sealant dots or stripes on the mat to make it more grippy.

Dont bivy on slopes ?

Mat out side for me ( rab survival no alpkit)

Macpac Bag here and I get my mat inside, fits the profile of the bag well, if not drink more

Macpac Bag here and I get my mat inside, fits the profile of the bag well, if not drink more

trial run Bivvy in the back garden last week and had to jack it in due to the cold

There’s your problem, too easy to give up.

I fit a 3/4 ultra-light thermarest in my Hunka no problem.

large army goretex bag for me.
Tons of room for a mat inside, skyhigh bag and my 6’4″ bulk

I run a 3/4 thermarest inside an ME bivvy -good enough for High Alpine use – for the cold ,use a single malt !

Mat under bag for me.

Helps keep the bivvy bag off wet and dirty ground thus stays cleaner and breathes better. Can’t say I have ever rolled off and I’m quite a restless sleeper, esp outdoors.

My bivvy bag is waterproof, my mat isn’t- so important for multi day use to keep the mat dry ,also the mat could get heavy if saturated .As for it breathing better , can’t see how inside or underneath would make much difference tbh

Definately mat inside bivvi …

… and I roll it up like that too … mat and sleeping bag set up inside bivvi bag and the whole show rolled up and into a dry bag and onto the bars … I also keep my mosquito head net in the sleeping bag pocket so everything is ready when I need it.

Yeah inside for me too.

Buy a Hunka XL

Much is going to depend on the bivvy bag. Something with a light base is soon going to get knackered if it’s directly on the floor.

Some bags (many Rabs as an example) have a much tougher base so they’ll withstand being placed on the floor. Something like a lightweight MSR or TN Moonlite would get damaged/worn pretty quickly.

A bit of poly sheet used as a groundsheet weighs nowt and works wonders 😉

Just been to alpkit.com – can’t believe they are just £30 or £40.

Can you get them from anywhere else as Alpkit are currently out of stock of the XL?

Inside! (HunkaXL)

Bed for the night by fantasticmrmatt, on Flickr

Depends on your mat too i guess – mines a themarest neo air – when inflated its thick and comfy how ever its also not got anything to get wet and heavy 🙂

Army issue sleeping bag, bivvi bag and rollmat. Sleeping bag in bivvi bag, bivvi bag on top of rollmat. In 15 years and counting, I’ve never had a problem with that setup on countless exercises and deployments around the world in a wide variety of terrains and climates. I imagine you could get all three items off eBay for under £50.

Admittedly the issue sleeping bag is a little on the bulky side, even when packed into the compression sack. If you’re taking your sleeping gear in a car to then camp at a static location (often do this at Dolgellau when visiting Coed y Brenin for a weekend), then this isn’t really an issue. If you’re carrying stuff on a bike though, most of Snugpak’s Softie range of sleeping bags compress down pretty small.

Mat inside for me. 3/4 length multimat and Rab Storm

The mat goes underneath the bag, it’ll prevent the bag wearing unnecesarily. You won’t slip off it if you pick your sleeping location (or carry a folding shovel to dig a shell scrape) You need air circulating and moisture to escape out the top of your sleeping bag. This is why the average infantryman undoes their boots, pulls their trousers below the crotch and undoes their jacket and leaves it open, avoiding sweat issues. The science is there.

In this case, either your sleeping bag wasn’t a high enough rating (and the use of a bivvie bag adds one season to it) or you trapped your sweat inside the bag, it sat on your skin and then tried giving you hypothermia.

mat outside for me

I’m mthinking of bivvying tonight even though its pissing down

mat inside under the sleeping bag…

Thanks for the ideas, guys.
I didn’t feel damp whan I whimped-out, just cold.
I’m not a big bloke but the Hunka envelope got used up by the width of the mat.
I’ll try with the mat outside but I will be worried about punctures!Maybe the plastic sheet under it.
And I will keep my eye open for a HunkaXL. Any down-sides to the bigger bag, other than pack size?

Got a US waterproof cape to mess around with for a shelter now, too.
What will the neighbours think?
Probably the same thing they think when they see me practicing attempting bunnyhops out the front of the house.

Yeah, the cape you tie off the hood, and it has eyelets round the edge you can use to bungee it between trees for a roof over your head. The bungees weigh a bit though.

You shouldn’t puncture the harder reinforced base of the mat. It’s only if you go somewhere like southern europe where they have that thorn grass.

inside on an alpkit xl (normal hunka for the missus). its an old thermarest too a bit like one of these!