Chimney care for New Bedford: three-deckers, two-families and whaling-era brick

New Bedford’s housing tells the story of the whaling trade and the textile mills that followed it. The Massachusetts Historical Commission’s survey notes something unusual for the region: the city never really adopted the center-chimney Cape. Instead, its early builders put up three-bay and four-bay cottages and houses, most on raised basements with interior chimneys, packed tightly along a grid of streets. Whaling money then produced everything from tenements to mansions, including brick Greek Revival houses with tall end chimneys linked by parapets. Many of those stacks are now around 180 years old, laid in soft lime mortar and often without liners.

The layer most people picture came next. The survey describes two-family houses through the 1880s and then, from the 1890s, large districts of three-deckers along Cove Street in the South End and Acushnet Avenue in the North End, with Clark’s Point following the same pattern. The Census Bureau’s numbers show how much of that remains: an estimated 52.1% of the city’s housing units date from 1939 or earlier, and 46.7% are in two-, three- or four-unit buildings. A typical three-decker chimney is a tall brick stack rising through the building, originally serving a coal or wood stove on each floor.

Today about four in five occupied homes heat with gas. That change matters for those old flues. A tall masonry flue built for hot coal smoke is often too large and too cold for a modern gas boiler or water heater, whose cooler, wetter exhaust can condense on the way up. The condensation and its acids attack mortar and brick from the inside, which is why tile fragments, staining and crumbling mortar at the base of a heating flue are common findings in older multifamily buildings.