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,