Your Local Hunterdon County Chimney Team

Historic towns on the Delaware and the South Branch

Hunterdon's towns wear their age openly. By 1980, 65% of Flemington was on the New Jersey Register of Historic Places, and the borough is now on the National Register as the Flemington Historic District. Nearly all of Lambertville was listed as a historic district in 1983, and many of its 18th- and 19th-century houses have been restored. Frenchtown's district covers buildings and planning from 1795 to 1931, and the Clinton Historic District takes in much of that town.

Out in the townships, history is spread across farms and crossroads villages. Oldwick, in Tewksbury, has more than 100 structures in Victorian, Federal, New England and Georgian styles, and its district counts 127 contributing buildings. Readington has the Readington Village, Whitehouse-Mechanicsville, Stanton and Taylor's Mill districts, and the John Reading Farmstead in Raritan Township dates from 1760. High Bridge shows the industrial side: river power there fed one of the first ironworks in the country, begun in the 1740s.

Countywide, Census estimates for 2024 put about 17% of homes before 1940, while the single busiest decade was the 1980s, at about 21%. So a Hunterdon street can hold a stone farmhouse and a 1980s colonial side by side, each with a very different chimney.

Before you change an old chimney

Because so much of the county sits inside historic districts, ask before you rebuild. Work on a landmarked property, or one in a district your town regulates, can need approval from the local historic preservation body, particularly for changes to height, brick, cap style or crown that show from the street. For homes outside those districts, check with your town's building department about permits.

Old masonry also follows its own rules. Historic brick and lime mortar are softer than modern materials, and a hard cement mortar can trap water and crack the brick around it. Matching the original mortar keeps the chimney sound and keeps its look.

Oil, propane and wood

Hunterdon leans heavily on delivered fuels. Census estimates for 2024 put utility gas in about 47% of occupied homes, fuel oil in about 25%, propane or other tank gas in about 10% and wood in about 2%.

Each fuel leaves its own mark. Oil burners leave soot and scale in the flue, and an out-of-tune burner can build that layer quickly. Propane exhaust is full of water vapor that condenses in a cold chimney and wears on mortar and tile. Wood stoves and fireplaces leave creosote, which burns, and has to be removed when it builds up. A house with an oil boiler in one flue and a wood stove in another needs both looked at.

Hill country winters

Much of the county is hilly, rising to about 1,060 feet in Lebanon Township in the Highlands. In Flemington, average January lows are about 19 degrees Fahrenheit, and the record there is 18 below zero, from January 1984. July brings the most rain, about 5.2 inches on average. Higher ground runs colder than the river towns: Clinton's January average is 29 degrees, while Lambertville's is about 31.

Those months bring many nights below freezing. Water that gets into masonry through a cracked crown, a missing cap or worn joints freezes and widens the gap, and the large stone and brick chimneys on old farmhouses can lose mortar deep inside the joints, not only on the surface.

A checklist for Hunterdon homes

Put together, the history, fuels and weather point to a handful of habits:

• Inspect every flue at least once a year, the interval NFPA 211 sets for chimneys, fireplaces and vents.
• Clean oil-boiler flues whenever deposits build up, and check the base of the chimney for fallen scale.
• On farmhouses with big stone or brick chimneys, look for open joints, loose upper courses and gaps where the chimney meets the roof.
• Keep a screened cap on every flue in wooded areas to keep out animals and leaves.
• Use a mortar that matches the original when repointing historic brick.