I usually store mine in carport with the top up and vents open to let air circulate. If there is going to be a lengthy bout of bad weather I'll put it down.
Always down, that way the vinyl is not exposed to UV or the elements and wont degrade. I've done tests with both ordinary digital and infrared thermometers and the van is cooler during summer with the top down. I also have one of those inexpensive caravan covers like ALDI had on sale on Saturday. $100 = cheap protection.
If I have no intention in using the van for an extended period (eg, a whole year laid up), I slide out the plastic strips from their pockets. (Jayco use sprung plastic strips in pockets to assist the vinyl to always fold inwards neatly)
Thanks people, I have a Aldi cover and remove it every now and again, I was worried last few weeks with van internal temps over 50C every day so I removed cover and opened vent still very hot. Was worried about the vinyl being stripped of its plasticises and becoming brittle and cracking at the creases when I leave it down all the time.
I may give the vinyl a spay with Armor All and see if that helps.
Cheers,
Brian
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Brian & Nada retired and > "Ready to live the Dream" Live in the Shire!
76 series V8 Landcrab with Jayco Starcraft Outback Poptop