Spot on,that's what happened to my saph,the shell was pretty good before I let it stand on my mums drive and a ton of weeds grew up and nested below it.
Full resto required!!!!

Probably would have wanted one anyway but perhaps it could have been contained rather than getting as bad as it did.

As for car covers ruining paint that's a very common issue,used to see a LOT of it in the garage.

I think its cos basically the water stored keeps converting back into vapour then the sun hits it so it's almost boiling up under there,the vapour has nowhere in particular to go so heats the paint up.
Obviously if this is exposed out in the sun it can get to disperse a lot easier not bubble under the cover.

 

Each time I hear that someone has bought, or thinking of buying a car cover for outdoors, I advise them not to if it's had paint recently.

Micro Blisters will form beneath the top coat layer due to poor preparation. Once it appears the only solution is a respray.

The cause of blistering is saturation of the film by exceptional levels of atmospheric humidity, together with the presence of water-soluble materials, either absorbed into the film or present on the surface before painting. The blisters are formed when the moisture eventually escapes from the film as humidity decreases and temperature increases. The pressures formed in the film are enormous and often sufficient to deform the film into blisters. Where very low temperatures are involved, moisture freezes in the film and this leads to weaknesses in adhesion which make subsequent blistering much more likely.

A simpler explanation:
If layers of paint are applied (wet over wet) without sufficient time between coats it can trap moisture.
Moisture will eventually travel back to the top surface usually in the form of Micro Blisters.

 

the advantage of the car coon is it doesn't touch the paint work anywhere! and it has air circulating to dry out what ever is inside!

Bentley and the Italians use them a lot!

 

carcoons are the (more expensive) way forward.......

 

i like the look of the carcoon but how much does it cost to run one per day with the fan running brendan