How a southwest Ohio winter goes after your chimney
A chimney in Fairfield endures a punishment that has nothing to do with how many fires you light. The masonry stands fully exposed to the whole arc of a Cincinnati-metro year, the muggy heat of a Butler County summer, the soaking rains that roll up the Ohio Valley, and then the relentless freezing and thawing of the cold months. Brick and mortar are porous by nature, so they pull in water during every wet spell, and when that absorbed water freezes it swells and forces the masonry apart from within. Every cold front widens the cracks a little further, and the crown at the very top, the most weather-beaten surface on the entire stack, is almost always the first piece to surrender.
Burning season piles on a second, entirely different kind of damage. Every wood fire lays down creosote along the inside of the flue, a sticky, flammable film that thickens in layers and steadily shrinks the channel the smoke has to climb. A flue even partly coated in hardened creosote is both a fire hazard and a draft problem at once, because the same deposit that can ignite is also strangling the airflow the fire needs to draw. The two threats attack opposite ends of the chimney together, water and ice gnawing the structure from the top down while creosote stacks up in the flue from the firebox skyward, which is precisely why a chimney here wants looking at on a schedule rather than only once something has visibly gone wrong.