What a Linden winter does to a stack standing in the open
A chimney in Linden gets worked over by the weather whether or not a single fire is ever lit in it. The masonry stands fully exposed to the whole range of a North Jersey year, the muggy heat of a Union County July, the wind-driven rain that rides in off the coast, and then the relentless freeze and thaw of January and February. Brick and mortar are porous by nature, so they soak up water through every wet stretch, and the moment that trapped water freezes it swells and levers the masonry apart from within. Each hard cold snap widens the cracks a little further, and the crown at the very top, the single most exposed surface on the whole chimney, is almost always the first piece to surrender.
Then there is the heating season, which is a wholly different sort of wear. Every wood fire lays down creosote on the inside of the flue, a sticky, flammable film that builds in coats and shrinks the channel the smoke has to climb. A flue even partly varnished with hardened creosote is two problems at once, a fire waiting for a spark and a draft that has been choked down, since the same coating that can ignite also strangles the airflow the fire needs. The two forces gnaw at opposite ends of the chimney together, water and ice prying the structure apart from the top and creosote stacking up in the flue from the firebox, which is precisely why a chimney around here wants looking at on a calendar rather than after something has plainly gone wrong.