Union County, New Jersey
Chimney Leak Diagnosis in Cranford, NJ
Cranford has a large stock of older, owner-occupied houses. When a chimney leaks, working out where the water enters is most of the job.
Cranford, in Union County, is about 73% detached houses and 78% owner-occupied. The median build year is 1951, about 47% of homes predate 1950, and the ACS median home value is about $660,000.
This page is about leak diagnosis, because a damp spot near a chimney can come from many places.
The quickest way to waste money on a chimney is to fix the wrong part of it first.
Housing profile
What the housing mix means in Cranford
Nearly half the houses predate 1950 and most are detached. In older masonry, a crown, flashing or mortar joint may be sound while another is not, which is why tracing the entry point comes before any repair.
What we look at
Five places water can come from
Cap and flue top
Rain falls straight down the flue if there is no cap or the cap is damaged.
Crown
A cracked crown lets water into the masonry.
Masonry joints and brick
Eroded mortar and porous brick absorb water.
Flashing
Failed metal at the roof line sends water behind the chimney.
Condensation
A cold flue can sweat, which looks like a leak.
Learn
A diagnosis table for chimney leaks
| What you see | When it happens | More likely source |
|---|---|---|
| Water in the firebox | During rain | Cap, crown or flue top |
| Stain on ceiling beside the chimney | After heavy or wind-driven rain | Flashing |
| Damp patch on the chimney wall | Days after rain | Masonry absorption |
| Drips in the flue at certain times | In cold weather | Condensation |
The test is to work from the top down, checking the cap and crown first, then the upper masonry, then the flashing and roof. See why water is coming into your chimney for a full walk-through. Our flashing repair, crown repair and chimney cap pages describe the fixes.
If the roof has just been re-done and the leak persists, the chimney junction is a likely cause.
Checklist
What to note before you call
- Where is the water showing up?
- When does it appear: during rain, after, in wind?
- Has the flashing been resealed before?
- Is there a cap on the chimney?
- Any recent roof or siding work?
Questions
Frequently asked questions
Can you tell where a leak is coming from without opening anything?
Often, by inspecting from the top and following the clues. Sometimes a water test is needed.
Should I call a roofer first?
If the leak is clearly at the roof, yes. If it is near the chimney, a chimney inspection can save the cost of fixing the wrong thing.
Will sealant fix it?
Usually only briefly.
Chimney Academy
Guides that go with this page
Questions about your chimney in Cranford?
Call us, or send a scheduling request. We will contact you to confirm. Your appointment is not confirmed until we do.