They are various solution to prepare the floor where we assemble out carpet. Installation is possible on concrete. Sometimes we use also self-leveling concrete.
In preparation the floor very important is to fit all technical requirements to installation surface. For keeping high quality of surface, the floor should be smooth and flat. It should be also durable. Every raptures, unevenness are visible on carpet. If your surface is consist of asphalt, you will need also to speckle the floor.