I was told cracks usually appear near the top part of a chimney first. Why is that?
Answer
The upper section of a chimney experiences the most exposure to weather conditions. Rain, snow, and wind impact the upper portion of the chimney more than the lower sections of the structure. Over time these weather related cycles can weaken both mortar joints and bricks near the top courses because the top is more exposed then the rest of the chimney. Another reason is due to heat rising through the chimney flue hits the cold air during colder months & creates condensation on the upper part of your chimney. That condensation soaks into the bricks & chimney crown which freezes & thaws, expands & contracts and over time leads to cracks & deteriorating brick & mortar.
