Your Local Mercer County Chimney Team

Capital city, college town and suburbs

Trenton has been the state capital since 1790, and its older fabric is protected in districts such as State House, Mill Hill, Berkeley Square and Downtown Trenton Commercial. The Old Barracks, built in 1758, is the last colonial barracks left in New Jersey, and the city museum occupies Ellarslie, an Italianate house from 1848. Chambersburg, in South Trenton, is the city's historic Italian neighborhood.

Princeton has its own clusters, including the Jugtown Historic District around Harrison and Nassau streets, with buildings from colonial times, and the Mountain Avenue district. In Hamilton, the Isaac Watson House near White Horse dates from 1708, and in Ewing, William Green's farmhouse from 1717 still stands on a college campus.

Most Mercer homes are newer. Ewing has grown as a Trenton suburb since the early 20th century, Hamilton has no single downtown but several smaller commercial centers, and West Windsor has filled with planned developments since the 1970s. Census estimates for 2024 put about 17% of the county's homes before 1940, with the 1970s the busiest decade at about 15%.

Damp winters and heavy snow years

Southern Mercer, around Trenton, lies on the flat inner coastal plain with a humid subtropical climate, while the rest of the county is hot-summer humid continental. The land climbs northwest toward the Sourlands, and Baldpate Mountain in Hopewell Township is the high point at 480 feet.

Trenton's winters are cold and damp. The daily average in January is 32 degrees Fahrenheit, and there are about 17 days a year when the temperature never rises above freezing. Seasonal snowfall averages 24 to 30 inches but swings widely, and the Blizzard of January 1996 dropped 24.2 inches in a single storm. February is usually the snowiest month, matching the peak season for nor'easters.

A climate that hovers around freezing can be harder on masonry than a steadily cold one, because water in the brick freezes and thaws again and again. Snow that piles against a chimney on the roof also feeds water into the joints as it melts.

Gas furnaces and the chimney

Utility gas heats about 71% of occupied homes in Mercer County, according to Census estimates for 2024, with electricity at about 19% and fuel oil at about 5.5%. In older Trenton, Hamilton and Ewing homes, the furnace or boiler and the water heater often vent through a masonry chimney.

Gas exhaust does not leave heavy soot, but its moisture condenses on cool flue walls. In an unlined chimney or one with cracked clay tiles, that moisture erodes mortar from the inside and can push the exhaust where it should not go. A liner sized to the appliances is the usual answer when an inspection finds the old flue failing.

Keeping a Mercer chimney sound

Most repair calls here come down to water, age or a flue that no longer fits what is burning below it.

• Have chimneys, fireplaces and vents inspected at least once a year, as NFPA 211 recommends.
• Check the crown and cap each fall; a cracked crown lets melting snow straight into the masonry.
• In 18th- and 19th-century houses in Trenton, Princeton and Pennington, use a mortar no harder than the old brick when repointing.
• After a furnace upgrade, ask whether the water heater now vents alone into a flue that is too large for it.
• Clean the flue whenever deposits build up, whether from wood fires or an oil boiler.

Landmarks, districts and permits

Besides the Trenton and Princeton districts, Mercer has the Lawrence Township Historic District, which covers the village of Lawrenceville, the Pleasant Valley and Titusville districts in Hopewell Township, and the Windsor Historic District in Robbinsville. Pennington's Victorian railroad station of 1882 is on the National Register. Work on a landmarked or locally regulated historic property can need approval from the local historic preservation body. For other homes, check with your town's building department before work begins.