Why Chimneys Are the #1 Source of Roof Leaks in NJ Homes
Why Chimneys Are the #1 Source of Roof Leaks in NJ Homes
Ask any roofing contractor with years of experience in New Jersey where the majority of residential roof leaks originate, and you will get the same answer: the chimney.
Why the Chimney Is a Leak Magnet
The chimney is a vertical penetration through the roof — and anywhere a vertical structure meets a sloped surface, you have a seam that water wants to exploit.
Properly installed chimney flashing consists of several interlocking components:
- Step flashing — individual L-shaped metal pieces woven between the shingles and the chimney's side walls
- Counter flashing — a second layer of metal embedded in the chimney mortar joints that overlaps the step flashing
- Base flashing — sealing the bottom of the chimney where it meets the lower roof slope
- Saddle or cricket — a small ridge structure behind wide chimneys that directs water around the chimney rather than letting it pool
When any of these components fail — through corrosion, joint separation, improper installation, or simple age — water has a direct path into the roof structure.
Why NJ Homes Are Particularly Vulnerable
The freeze-thaw cycle in New Jersey is especially hard on chimney flashing. Metal expands and contracts with temperature. Mortar joints that hold the counter flashing loosen over decades. Caulk deteriorates, especially products that were not rated for exterior masonry use.
Many older NJ homes have "surface-applied" counter flashing — metal that was simply bent and caulked onto the chimney face rather than embedded in the mortar. This is a common shortcut that fails within 10 years.
The Proper Repair
A correct chimney flashing repair does not involve simply applying more caulk over the existing flashing. That approach may stop a leak temporarily — sometimes for a season — but it does not address the underlying failure.
A proper repair involves:
- Removing the existing step and counter flashing
- Cleaning the mortar joints where new counter flashing will be embedded
- Installing new step flashing integrated with the shingle course
- Embedding new counter flashing into freshly cut and repointed mortar joints
- Sealing the counter flashing terminations with an appropriate roofing sealant
If the chimney masonry itself is deteriorated, that work must be completed before new flashing is installed.
Troy & Henry LLC
We handle chimney flashing repair as part of comprehensive roofing and masonry services. A two-trade problem requires a two-trade solution. Call 1-800-886-2077.