What type of roof generally has no gables?

A mansard roof is characterized by its unique design, which includes two slopes on each of its sides, with the lower slope typically being steeper than the upper slope. This architectural style is designed primarily to maximize the amount of usable space within the upper floors, as the steepness allows for a larger attic area that can often be converted into living space. Unlike gabled roofs, which feature a triangular portion at either end where the two sloped sides meet (the gables), a mansard roof lacks this feature. Instead, the slopes of a mansard roof extend down to the eaves, creating a different visual profile.

In contrast, other roof types mentioned have gables. A flat roof typically has a horizontal design but can have parapets or walls rather than gables. A hip roof, on the other hand, has slopes on all four sides, converging at the top, leading to triangular sections at the ends. A gambrel roof has a two-sided roof with two slopes on each side, resembling a barn roof, both of which include gables. Hence, the defining feature of the mansard roof is its absence of gables, making it the correct choice.