What is the term that describes the vertical rise of a roof compared to its horizontal span?

The term that describes the vertical rise of a roof compared to its horizontal span is indeed "rise." In roofing terminology, rise specifically refers to the height that a roof reaches above a designated reference point, typically the eaves or the horizontal plane of the house, compared to how far that roof extends horizontally (the span). Understanding rise is crucial for accurately calculating not only the roof's pitch but also its overall structural integrity and aesthetic appeal.

This concept is essential in roof design, as it influences factors such as water drainage, the choice of roofing materials, and the roof's ability to shed snow or withstand wind. A steeper rise can often lead to improved performance in these areas.

The other terms listed have specific meanings in roofing but do not describe the relationship of vertical rise to horizontal span in the same way. The "ridge" refers to the highest point of a roof where two slopes meet, while "ridge board" is a structural component that runs along the ridge, providing a point of attachment for rafters. "Ridge vent" is a type of ventilation installed along the ridge that allows heat and moisture to escape from the attic space. Thus, "rise" is the most accurate term for the relationship in question.