be built from the ground up

To be constructed, created, or developed with no existing foundation to build upon; to be built from scratch. This proprietary software has been built from the ground up to take full advantage of the power of our new computer hardware. This company was built from the ground up by my great-grandfather—there's no way that I would ever sell it. I know you're confident in your idea, but this business you're proposing would have to be built from the ground up—are you really prepared for that?