What a century-old Newark stack is up against
A chimney in Newark stands fully open to the weather at the tallest point of the house, and it absorbs everything a New Jersey calendar throws at it. During the heating months, every fire sends warm, acidic gases climbing a flue that is usually colder than the appliance feeding it, and wherever those gases cool against the lining they leave creosote and moisture behind. The dense, century-old housing across the city compounds the trouble, because so many of these flues are the wrong size for the appliance now tied into them, were built oversized for coal, or run alongside a neighbor's flue in a shared stack. An undersized or sluggish draft lets even more deposit settle where it never should, and that buildup is precisely what can turn a routine fire into a flue fire.
Then there is the season that takes a chimney apart from the outside in. Water is what destroys masonry, and the freeze-and-thaw rhythm of an Essex County winter is tireless about finding any way in. Rain and melting snow soak into a porous crown or an open mortar joint, freeze overnight, expand, and lever the material apart a little further with each cold spell. A thread-thin crack noticed in autumn can be a crumbling, spalling crown by the end of March, and the water that crack lets in runs straight down into the flue and the smoke chamber, where it rusts the damper, breaks down the liner, and eventually shows up as a stain on a ceiling inside. That is the whole reason we press homeowners to have the chimney looked at before the cold arrives, while there is still time to cap and seal the stack for the winter ahead.