In the last ten years I have
looked at over a thousand
chimneys. Less than twenty
of these were properly flashed. It
may take a few years, but a poorly
done flashing job will eventually
cause expensive repair problems
for the homeowner, and maybe a
callback for the builder.
Flashing Requirements
What is a flashing job required
to do? The obvious requirement is
to seal the opening around the
chimney where it goes through
the roof. Second, the flashing
should provide a sliding connection
that will allow the building
to move independently of the
chimney. The third, not so obvious
requirement is to prevent the
transfer of water, absorbed by the
masonry above the roof, into the
masonry below the roof. The
flashing