The earliest known exampl.
Mansard roof with flat top.
However unlike a traditional mansard roof these roofs had a flat top.
Since the top of the roof is flat snow can accummulate and eventually cause water leaks.
You can mostly see concave mansard roofs in large stately mansions that date back to the 19th century.
It depends upon what type of design customer wants to implement.
A mansard or mansard roof is a four sided gambrel style hip roof characterized by two slopes on each of its sides with the lower slope punctured by dormer windows at a steeper angle than the upper.
This video shows one way to sketch a modified mansard style roof using one flat shed roof for each face of the one you want to imitate.
Mansard roof was not used quite as often in traditional homes despite it was featured in many high rise residential buildings especially in the late 1960s and 1970s.
However unlike a traditional mansard roof these roofs had a flat top.
Later on many small commercial buildings also adopted a mansard style roof.
The steep roof with windows creates an additional floor of habitable space and reduces the overall height of the roof for a given number of habitable stories.
But you cannot misunderstand them as straight panel roofs.
There is a sort of visible distinction between flat roofs and mansard roofs.
It is best to inspect your roof annually in order to prevent erosion.
The upper slope of the roof may not be visible from street level when viewed from close proximity to the building.
Later on many small commercial buildings also adopted a mansard style roof.