"Learned a hard lesson today. Took my coach to winter storage & was left with 4 tire imprints on my nice concrete driveway.
From reading the comments, it seems that you and several others may not have learned the most important lesson from your unfortunate discovery. The most important lesson follows:
The liquid that drained from your tires was sucked out by the concrete. It will also be sucked out by any other porous surface, like most gravel. The liquid is the UV protectant which keeps the sunlight from damaging your tires. This draining of the UV protectant will significantly reduce the life of the tire.
For this reason an RV should never be parked on an absorbent surface for a long period of time. If you are going to be parked longer than a few weeks, it is worth the time to use a pad.
You may ask where i got this information. It came from a Michelin engineer.
It is also covered ,in less detail, in the Michelin RV tire Manual which can be found at the link below.
The exact wording from the manual is:
"2. Place a barrier between the tire and the storage surface. Suitable barriers include plastic, plywood, cardboard, or rubber floor mats."
The engineer did not particularly like cardboard and suggested dish drain mats from Walmart. They are cheep and prevent the problem you experienced.
NOTE: The document is worth a read as it contains several other tips i have found useful. Happy camping.