June 2, 2004
Sometimes the importance of the parapet wall gets overlooked, and the focus of work is directed towards other parts of the building structure. Of course there are many important aspects of a building’s structure and each of these aspects function to keep the building strong and secure. Of these aspects, though, the parapet wall is one that we often bypass when thinking about the building’s structural integrity as a whole. To begin, the parapet is simply the area of the wall that is above the roofline. This implies that both sides of the parapet wall are exposed to the effects of all weather factors. Especially important factors are extreme temperature change and drastic amounts of rain. When rain does affect the parapet structure, it is most likely that the cause of the problem is at the top of the parapet wall because it is this area that is most vulnerable for water-related problems. The water enters through mortar head joints in the cap through gaps in metal cap seams. It should also be noted that the parapet wall expands and contracts at a quicker rate than the masonry below it. The masonry below the parapet can rely on the weight of encompassing masonry to help control and contain movement. The parapet wall does not have such weigh on top of it and therefore has a more difficult time maintaining it’s original form after temperature causes the walls to expand and contract.
As published in the Superior internal newsletter, June 2004