A good part of my metalworking business is specialty flashings. If a builder has a large chimney, a barrel dormer, a cricket, or some other complex shape to flash, I'll get a call. Not only do most builders lack the equipment to do these jobs, but they have an incomplete knowledge of how flashings work. For instance, most forget that water can run uphill as well as downhill. Many of the leaks I see occur when high winds or melting snow and ice cause water to work its way up the slope of a roof. The flashing works fine under normal conditions, but as soon as a big northeaster comes along,