I have used French drains on buildings where I didn't want to install and maintain gutters. The roof shed straight into a gravel path (no soil coverage) around the building that had perforated pipe leading to a dry well. Worked perfectly. In one case the pipe had to be very shallow so I used crusher-run (404) aggregate to form better support around the pipe at the surface. Again, worked perfectly. You really have to watch the details and plan things out meticulously for the given situation.