Why do houses have shingles and slanted roofs, but most other buildings have flat tops?

Question

Why do houses have shingles and slanted roofs, but most other buildings have flat tops?

In: 8443

Answer 1

Just to exapand on what some others have said, a “flat” roof is rarely flat. They usually have a small enough pitch to seem flat but allow run off to other drainage.

The ones that are flat are designed to remove water in some way, like evaporation, which is partly why some roofs have stones on them, (the likes of portacabins etc)