A parapet is that part of a wall entirely above the roofline and has been an important element of architecture for more than 2600 years. Although still in general use, parapets are much maligned.

They have been variously described as particularly and extremely vulnerable, and susceptible to displacement, cracking, efflorescence, and spalling. One expert likened parapets to a plague, stating that they are the source of more moisture problems than any other building element.

Parapets are exposed on three sides and subjected to high winds, severe rain, temperature extremes, melting snow, aggressive weathering, cracking, and radiation. Although water permeance and durability are important aspects of wall performance, they are not considered in this article.

This article discusses the structural integrity of parapets designed in accordance to the Building Code Requirements for Masonry Structures (Buildings, 2001). In short, such walls are dangerous.