Chimneys are usually all but forgotten until its winter and you can not wait to build that first fire, but sometimes a problem arises that demands your immediate attention. Water! Chimneys have the most exposed brick/rock on your home, so the severe weather with freeze/thaw cycles and rain takes it’s toll. Brick and mortar joints are porous, so when it rains the water is absorbed. The fact that brick are porous is what makes them stick together when laid called a hydraulic bond. So with all this being said your masonry chimney is essentially a big sponge or wick on the exterior of your home or above your roof line. Trying to diagnose exactly where the water is penetrating can be tricky. Many times it’s assumed water is coming through the flashing at the base of a chimney or down the flue, but in most cases it is caused by years of exposure to the elements. This exposure can wreak havoc on a masonry chimney’s structure.
