Which racking option will better suit my flat roof: a ballasted system, or one that requires roof penetration?

Roof penetration and ballasted solar racking systems for flat roof differ in a few aspects:
While the installation is typically simpler and cheaper for ballasted systems, and thus require fewer inspections, and is easier to remove, solar racking systems that require roof penetration are typically lighter, easier to maintain, allow a larger span of tilt angles, better accommodate low profile obstructions on the roof, and minimally impact the drainage.

Read more about the comparison between these two options in this blog post:
Solar racking for flat roof: ballasted or roof penetration?