Mass masonry walls have always been the standard for building weather-resistive structures. A thick, redundant masonry wall acts as a blotter absorbing wind-driven rain through the exterior exposed surfaces and by its shear mass. The wall eventually dissipates the force (wind) and pressure differentials, maintaining a dry interior. While there are as many variations to these basic design principals as there have been architects, mass masonry has proven to be a most durable basic building wall system.
The first adobe hut included the extension of a thatched roof to over sail the mass masonry walls below. This arrangement provided the wall protection from above, and an architect asked, “Why don't we stop the roof on the interior face of the wall and hide it?” Thus, the parapet (vertical extension of the mass masonry wall) was invented.
This milestone in the evaluation of the building envelope added considerable complexity to construction, design, and maintenance in several ways.