The roof is flat. Any roof with a slope of less than 7 degrees.

Flat concrete roof (waffle slab system), Vancouver, Canada (S. Brzev)

Flat concrete roofs, India (S. Brzev)
The roof is flat. Any roof with a slope of less than 7 degrees.

Flat concrete roof (waffle slab system), Vancouver, Canada (S. Brzev)

Flat concrete roofs, India (S. Brzev)