The term plumbing is derived from the Latin word "plumbum," the name of the metal lead that was the preferred material used by the Romans to construct their empire's water supply systems. This bit of history is even relevant today as the continued use of this potentially toxic metal has made headlines because of recently exposed problems in the Flint, Mich., water supply.
Although sags along roof ridgelines can be discovered at any time, in northern climates they are often attributed to the effects of a past snow load. To make an educated analysis of the actual cause of this phenomenon, one must have a basic understanding of the structure and the loads to which it has been subjected.
Ice dams and their resultant leaks are often a chronic and expensive problem in those regions where snow-covered roofs are a common occurrence. To understand their detection, cause, and prevention requires some understanding of the dynamics of a structure's construction, insulation, and ventilation.
A space heater is a device designed to warm a small area. These devices are typically portable, but the category does include gas- and wood-fueled models that are permanently installed; however, these are not the focus of this article.