Answer

I think you could call the challenges of a flat roof “inauspicious,” because a flat roof will touch your pocketbook more often and more deeply than a pitched roof:

• They don’t last as long.
• They have a greater tendency to leak (and make it hard to find the source of the leak).
• They are more expensive to maintain.

A business whose building is painted in dark colors and has a flat roof can have higher employee turnover. That’s the only feng shui advice on flat roofs I’m aware of — but you notice that this relates solely to commercial property in dark colors.