I was just doing some internet searching on some terms and phrases, and this idea or concept just doesn't make sense: It is said over and over and over again that you want a "breathable car cover" so the water that's trapped inside or under it to escape. Yet what is never explained is - how does water get trapped under it if it's an actual impermeable membrane - like a sheet of 6-mil poly vapor barrier? Or all-weather car covers that claim to be water proof - presumably they are not "breathable".
Your roof is not "breathable" - in the sense that water can pass through it. Your house would be a wreck in no time if your roof / shingles were "breathable". Same for your walls, with vapor barrier just behind the drywall. Cars are not made of wood. What's the point of breath-ability?
I came across one explanation - you can get moisture trapped under an impermeable cover from the ground (or pavement or what-ever) under the car. To which I say - ok, put a vapor barrier sheet under the car to solve that.
So what's wrong with throwing a few thick moving blankets on the car from bumper to bumper, then covering with a poly vapor barrier? The poly is clear, you can see right through it, you'll see if the blanket is getting wet or if condensation is forming under the poly.
I keep coming back to the idea that if you can wrap the car air-tight, vapor-proof bag, load the inside with descicant, that is best vs exposing the car to constant ambient air with uncontrollable huge swings of humidity and temp changes.
