Excessive condensation

Hi friends
With this recent van I have, I've found that there is a heck of a lot of condensation on the fiberglass pop top (Dormobile) in the shut position. So much so that it's like a drippy cave. We have had a spell of cold weather but it seems to be a lot wetter than I would expect.
My questions are.
What's causing it? Can it be prevented?
I've removed the soft furnishings and I've put in a dehumidifier, but if I cant prevent this, the van will be full come spring time. I'll need a scuba set.
Do you think it could be damp seeping in that's causing it?
As always, thoughts and suggestions are appreciated.
Thanks
Andy.

Hey there Aardvark, there’s usually two or three things causing this and it’s going to be much more prevalent at this time of year. The formula for success is called HIVE, it’s Heating versus insulation versus ventilation versus excess moisture. The reason it’s more apparent at this time of the year is because of the recent drop in temperatures :roll: another issue is all around this area is a huge tin can (van) that’s gotten extremely cold too and metal is thermally conductive. This also happens more so with older vehicles especially campers that are full to sodden with moisture from cooking and breathing vapours. Ventilation is the first bit but will only work if the air replacement is dry ( not likely now) . Insulation will deffo reduce your air contact with the cold can. Heating isn’t a goer if the vans left unattended so we have to deal with excess moisture. Remember, the bits you’re seeing are more than likely not the worstest bits, that’s usually hidden behind the ceiling covering. Dehumidifier is great but a bit of a bind. Moisture traps and shut them windows is the way forward until you can help the insulation in the warmer weather. Unibond ones are available from the likes of B&Q and have a refill looks like a toilet block from the gents urinal. These are a bit like a five inch football and attract then trap the moisture, but the downside is they are easily tipped or knocked over. I made a holder for mine from a plastic celebrations box or roses box, I cut a hole in the top and fitted the ball then secured it with large elastic bands kindly left in my front garden by the posty. Two of these in your van will sort it, one back and one front.

Ozziedog,,,,,,,,,,,Haynes motor museum don’t have these issues do they :lol:

If you have access to a 240V power supply you could leave a thermostatic controlled oil radiator inside over the winter. I'd do this along with a moisture trap and leave the front vents open.

I also have a cover over the top. I suspect it doesn't cost me much, and that it's a lot less than it would to repair or change anything.

Also makes for a nice hideout for when the wifes in the rampage about something I've not done (so REALLY worth the cost on those occasions)