Chimney Services in South Plainfield, NJ

What the numbers suggest for chimneys in South Plainfield

Census estimates date 40% of South Plainfield's 8,530 housing units to 1940 through 1959, 26% to the 1960s and 1970s and 18% to 2000 or later. A brick chimney built in the 1950s may have outlived more than one roof covering, and every reroofing job disturbs the flashing where chimney and roof meet. Our guide to planning the chimney around a roof replacement covers the timing.

Gas from the utility line heats about 84% of occupied homes, electricity 9% and fuel oil 4%. A chimney here may serve a furnace or water heater as well as a fireplace, so a leak at the roof line can wet the flue and the connections below it, not only a ceiling.

Detached single-family homes make up 78% of units, so most owners are responsible for their own roof and chimney. These are borough-wide estimates and do not describe any specific house.

Two layers of metal at the roof line

Chimney flashing works in two overlapping parts. Base flashing, often installed as step flashing, is woven into the roof covering and turned up against the masonry. Counterflashing, also called cap flashing, is set into the chimney and folds down over the base flashing, so water running down the brick is carried onto the roof surface instead of behind it. Keeping the two layers as separate pieces lets the roof and the chimney shift slightly against each other without tearing the seam open.

The Copper Development Association's chimney flashing detail describes base flashing that extends at least 4 inches up the wall and onto the roof, and cap flashing set into a reglet or built as a two-piece receiver and counterflashing. For a chimney that sits on a single roof slope, it calls for a cricket on the high side to divert water around the chimney. The Brick Industry Association likewise lists chimneys among the places where proper design requires flashing. Our chimney flashing guide includes a diagram of the layers.

Tracing a leak at the roof line

Water that appears on a ceiling or wall near the chimney can come from the flashing, but also from the crown, the cap, porous brick or the roof itself. Every visit starts with an assessment. That includes a look at the roof and into the attic where it is safe to get there, and, when the source is still in doubt, controlled water testing applied to one area at a time.

Clues that point toward the flashing in particular include:

• Counterflashing pulled out of its joint or bent away from the brick.
• Rust, gaps or thick layers of roofing tar where the metal meets the masonry.
• Staining that shows up during wind-driven storms and lines up with one face of the chimney; the guide to wind-driven rain explains why direction matters.
• A missing or flattened cricket on the uphill side.

Repairs range from resetting counterflashing into a fresh mortar joint to replacing the full set, which is simplest to coordinate while the roof is being redone. See chimney flashing repair. You get photos of what was found before the work and of the finished flashing after it. On permits, New Jersey's Department of Community Affairs treats reroofing of a detached one- or two-family house, in any amount, as ordinary maintenance under its 2018 code alert.

Local questions

Sources

1. U.S. Census Bureau, American Community Survey 2020–2024 5-year estimates (tables B25034, B25040, B25024), via Census Reporter
2. Copper Development Association: Stepped and Chimney Flashings (Copper in Architecture design handbook)
3. Brick Industry Association, Technical Note 7: Water Penetration Resistance, Design and Detailing (PDF)
4. NJ Department of Community Affairs: Significant Changes to Minor Work and Ordinary Maintenance (2018 code alert, PDF)