Using this on recommended commercial carpet without padding but it's not thick enough to maintain a level rolling surface. Probably OK for super-thin carpet.
I have purchased 2 of these in the last 3 years. One began to crack and turn brittle within 6 months. The other is about 2 years old and has to be replaced because it has pretty much disintegrated. I would not recommend this. In particularr don't use any kind of commercial cleaner on it as it will turn brittle and deteroriate faster.