North Texas is hard on chimneys
Long hot summers, sudden heavy rain, hail and freeze-thaw swings all attack the same materials. Concrete crowns crack, galvanized metal rusts, mortar erodes, and sealant fails faster than the manufacturer's label suggests.
The five usual entry points
A leak is a symptom. One of these is almost always the cause.
- • Flashing at the roofline — the most common source, especially where roofing tar was used as a patch.
- • Chimney crown — cracked, flush-poured, or missing an expansion joint.
- • Chimney cap — missing, undersized or blown off.
- • Masonry — unpointed joints and porous brick absorbing water directly.
- • Chase cover — rusted through on prefabricated chimneys.
Diagnose before you seal
Sealant applied over the wrong failure hides the leak for one season. Proper diagnosis uses controlled water testing on one area at a time, plus a camera inspection, until the entry point reproduces.
Ask for photos of the failure. If a contractor cannot show you where the water is entering, they are guessing.
Repair order matters
Waterproofing goes on last. Sealing a saturated or unpointed chimney traps moisture inside the masonry and accelerates spalling. Fix the structure first: flashing, crown, cap, joints. Then waterproof with a vapor-permeable product that lets the masonry breathe.