Wet duvet in pop top - California 6.1

Loz2286 · Apr 19, 2022

On a recent trip away we had a bit of trouble with the pop top. My wife sleeps upstairs and I'm downstairs with the dog. My wife's duvet was wet on most mornings even when it wasn't raining at night. Is this caused by condensation on the inside? Is the dew wicking through the canvas? The duvet is not soaking but wet on the surface along where it touches the canvas. We tend to sleep without the heater, preferring a heavy duvet.

Any thoughts folks?

flying banana · Apr 19, 2022

a few things here. you need to ventilate properly. i use heko wind deflectors and have the front windows open about an inch. i also run the heater all night. you are correct that condensation or rain is wicking through the canvass. it will improve over time. give it a good drench at home with a hose pipe and let it dry out. you could also try a topper. that will solve it.

Ozzy Pete · Apr 19, 2022

If you look at the construction of the pop top there is a lot of metal at the bottom of the canvas. This is very cold and a human body is very warm plus moisture from just breathing goes straight onto the cold metal surfaces. It’s probably that and the possibility of some morning dew on the inside of the canvas.
I think the later roof canvas’s Let in less moisture than the earlier ones but don’t forget it is only a tent after all.
Right from the start we sprayed ours with a waterproof spray which helped greatly stopping water coming in.

Volkywagen · Apr 19, 2022

There is an aluminium strip at the base of the canvas, if you lift up the bed from below you can see it more clearly. Saturday night both my children slept up there and in the morning it was dripping off. Maybe if your duvet it touching this it will be acting like a sponge? Condensation then pools on the step where the bed falls down and rests on.

Hawthorn37 · Apr 19, 2022

As mentioned, the metal base plate doesn’t seem to have any thermal break with the exterior, so it does get very cold if frosty outside. On the last 2 trips it was around freezing at night, and I expected to get condensation forming, but luckily we didn’t. We did run a heater (either electric fan, or the diesel heater) through the night, and maybe this was enough to raise the temperature to above the dew point. Another reason could be the relative humidity was low - which is typical for sunny days and clear frosty nights.

We‘ve also fitted wind deflectors to allow us to safely crack open the front windows.

Cali Phillip · Apr 20, 2022

Ozzy Pete said:
If you look at the construction of the pop top there is a lot of metal at the bottom of the canvas. This is very cold and a human body is very warm plus moisture from just breathing goes straight onto the cold metal surfaces. It’s probably that and the possibility of some morning dew on the inside of the canvas.
I think the later roof canvas’s Let in less moisture than the earlier ones but don’t forget it is only a tent after all.
Right from the start we sprayed ours with a waterproof spray which helped greatly stopping water coming in.

It's well known in mountaineering circles the single skin tents have lots of condensation problems, even when made in Goretex, they are for use in low humidity environments like high altitude missions.
The roof tent is effectively a single skin tent, either a topper or an isotope will help create a double skin.
After watching the California time video even the isotop does make the roof fully waterproof.
External topper is king for wet weather.

Loz2286 · Apr 20, 2022

Having spoken to the missus, she tells me that it was the top surface of the duvet that was wet. From the above and the fact that she uses a 15 tog duvet I have come to this conclusion. The duvet it self is so efficient that the outside top surface is cold enough to cause condensation. Reduced ventilation and lack of ambient heating coupled with cold nights/bright days has caused this. I'll try cracking the windows open a little and turning the heating on a little to improve matters.

Or am I barking up the wrong tree?

Ozzy Pete · Apr 20, 2022

Loz2286 said:
Having spoken to the missus, she tells me that it was the top surface of the duvet that was wet. From the above and the fact that she uses a 15 tog duvet I have come to this conclusion. The duvet it self is so efficient that the outside top surface is cold enough to cause condensation. Reduced ventilation and lack of ambient heating coupled with cold nights/bright days has caused this. I'll try cracking the windows open a little and turning the heating on a little to improve matters.

Or am I barking up the wrong tree?

If you are sleeping in the van upstairs with no heating on it’s no different to sleeping in a tent. Nice and toasty under the 15 tog quilt but absolutely nobbling outside. Just try everything. Don’t worry the weather will improve and it will be a distant memory....

Loz2286 · Apr 20, 2022

Thanks everybody. I'll try these things. My wife and I are a hardy couple and try to be well-prepared. It seems we're trying too hard to be "nails" and not using the heating VW provide.

flying banana · Apr 20, 2022

I don't get why so many are reluctant to run the heater. Use mine all the time and all night it's great

Loz2286 · Apr 20, 2022

flying banana said:
I don't get why so many are reluctant to run the heater. Use mine all the time and all night it's great

I think it might be because we were tent campers for years so we're proper hard core. :bananadance2

Cali Phillip · Apr 20, 2022

Loz2286 said:
I think it might be because we were tent campers for years so we're proper hard core.

We are from that background, -17C car camping the record.
I still don't like having the heater on, unless its really cold, just gets too hot for me even on setting 1 and well I am tight plus it saves battery in the winter.
If its really cold I program the heater for an hour at about 4am, about the coldest point ( always was on nightshift) and that takes the chill off. Then again for 30mins before I get up :bananadance2