Chimney Services in Union Township, NJ

What the numbers suggest for chimneys in Union Township

Census estimates show about 18% of Union Township's 22,068 housing units in buildings with two to four units, alongside 63% detached houses and 14% in larger buildings. In a two-family house, one chimney may carry flues for two heating systems, two water heaters and sometimes a fireplace, each used by a different household.

The housing is mostly older: about 20% was built in 1939 or earlier and 40% between 1940 and 1959. Chimneys from those decades typically have clay tile flue liners, and some of the oldest were built without one. That puts the condition of each individual flue at the center of any inspection; see flue vs. liner for the difference between the two.

Gas heats about 80% of occupied homes and electricity about 13%. A building where one unit changed to electric heat may now have a busy flue beside an idle one. These are township-wide estimates, not findings about any building.

Making a flue map for a multi-unit house

1. List every applianceWalk the basement and each unit. Write down every furnace, boiler, water heater, fireplace and stove, and which unit it serves.
2. Follow each connector pipeFrom each fuel-burning appliance, trace the metal pipe to where it enters the chimney and note the height and side of each entry. Do not open, loosen or move any pipe.
3. Count the flues at the topFrom the ground, or in photos from a roofer, count the flue openings on the chimney. If there are more appliances than flues, raise it with an inspector, since whether appliances may share a flue depends on the appliances and the applicable codes.
4. Have the map confirmedAn inspection confirms which flue each appliance really uses, checks each one's condition and notes any flue that serves nothing. A camera goes in where a flue allows, and you get photos of the findings.

A flue map earns its keep when one unit replaces a boiler, when a fireplace is reopened or when the building is sold. Keep a copy for each household. Our guide to chimneys with more than one flue shows typical layouts.

When two households share one chimney

Work on the outside of the chimney, such as the crown, cap or brickwork, affects every flue at once. Work on one flue, such as a new liner for one unit's water heater, affects only that unit yet has to fit beside the others. It is simpler to have one chimney inspection cover all the flues, so each household reads the same report.

Changes that call for a fresh look at the flue map

• A boiler, furnace or water heater is replaced in either unit, especially if the new one vents through a wall.
• One unit switches fuel, for example from gas to electric heat.
• A fireplace that has been closed for years is about to be used again.
• Crown, cap or masonry work is planned at the top of the chimney.
• The building is being sold.

Any of these can change which flues are in use or what they need, and an old flue map can quietly become wrong after a single project in one unit. For a change of appliance, an inspection before a new appliance covers the flue that appliance will use.

Local questions

Sources

1. U.S. Census Bureau, American Community Survey 2020–2024 5-year estimates (tables B25034, B25040, B25024), via Census Reporter
2. CSIA: The Three Levels of Chimney Inspections