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
