On my last trip to NZ in March I had many nights where I woke the next day to find loads of condensation in the tent and a damp down bag. I am not sure how much of the dampness was down to drips from the tent ceiling or just the fact that the air was quite damp and humid and as a result the bag naturally became damp.

I have a trip across Wales in 2 weeks time and given the weather and the fact Autumn is here I fear the cold damp nights and same condensation problem.

So, I thought about making / purchasing a sleeping bag cover, but I then thought that whilst a cover is great for stopping damp from above, what about the moisture vapour that you generate whilst in the bag. Will this moisture just get trapped inside in the bag and make the problem worse.

If they do work, what breathable material would people suggest and who can supply it. I have some ripstop nylon, but I have no idea how breathable it is and therefore it’s suitability.

what kind of tent are you using that your getting moisture drips inside ?

i have a rab pertex cover that i use when bivvying under tarp its not “Waterproof” but its pretty good at breathing i only get damp down in persistant rain if i roll over and end up with the bag in the rain.

in a tent it should be grand.

If you’re getting condensation in the tent you have zipped it up too tight – you need to leave some ventilation.

I have one of these:

Hunka

I haven’t yet had to use it to keep the bag dry, only when it was a bit colder than I expected and I only had a summer bag, but I’m sure it will work. It’s breathable, so as there’s a temperature difference to drive the moisture out it shouldn’t make the bag damp.

I use an ex British army sleeping bag cover. The material is MVP – Moisture Vapour Permeable, breathable but waterproof. Great kit, light, rolls up small and cheap.

You need to leave the storm flaps up if fitted around the base of the tent, if I ever used them it was only on the windward side unless we were expecting really bad weather. Sometimes you can increase ventilation by fitting extra loops to certain peg points and move the pegs further away to lift the edges of the tent. I also had a tent where the built in vent would fold down on itself so used to prop it open with a clothes peg wedged in.

Tent is a Force 10 200 Helium. Not top of the range, but then not a cheap one either. I must admit, I am guilty of zipping the outer flysheet right down to the ground. When I put the tent up I always try to get the out fly sheet as low to the ground as well, so that is not going to help matters.

I will try that.

I use an ex British army sleeping bag cover. The material is MVP – Moisture Vapour Permeable, breathable but waterproof. Great kit, light, rolls up small and cheap.

Do you get any condensation inside the bag?

^ Nope. I use one, because it’s supplied! They’re actually good bits of kit, one of the few that we don’t feel the need to replace with privately bought kit.

As others have said, airflow through the outer is essential. Adding other layers round your sleeping bag can also affect the few point so that it ends up inside the bag – and you really don’t want that.

I use a single-skin tartptent, the Lunar Solo. It works because there are mesh vents all around the base, the door is all mesh and the beak doesn’t zip down to the ground