My bike and cars are all in the garage. I have large pieces of scrap carpet from one of our construction jobs that I park both cars on top of. Never needed anything under the bike, but if I did I would probably just do the same with a piece of carpet.

I do bring my bike into the kitchen from time to time if it's just too hot outside to work on it. But I make sure it's dry and no major dirt build-up on the tires before bringing it in, though our kitchen is tiled so it wouldn't be a big deal.