Why does the same chimney leak keep coming back?
Usually because the repair treated a symptom. Sealant smeared over old flashing wears out in a few seasons, and if the mortar behind it is loose or the chimney lacks a cricket, water finds the same path again. A lasting fix rebuilds the metal and repairs what it is anchored to.
Tar and roof cement look like a quick answer, but they shrink and crack as the roof and brick move. A second coat goes on top of the first, and the joint becomes a thick crust of failed repairs.
Ask the roofer to explain what caused the leak and how their repair will differ from the last one.
Who repairs a leaking chimney: a roofer or a mason?
Both may be needed. The roofer handles the flashing, the cricket and the shingles around the chimney. The mason repairs bricks, mortar joints, the crown and the stack itself. A roofer should tell you which problems belong to which trade, and a good one will say so before starting.
If the mortar where counter-flashing sits is crumbling, the roofer may ask for the mason to repoint first, or may cut a new reglet in sound brick. Either approach works if it is done properly.
Chimney liners, caps and cleaning for a working fireplace are another trade again, and are not covered on this page.
Do old stone and brick chimneys need special care?
Yes. Historic brick and fieldstone chimneys often use soft lime mortar, and repairing them with hard modern cement can damage the masonry. Flashing is set into the joints, so the roofer and mason should work with materials suited to the wall, particularly in historic districts where visible changes may be reviewed.
Newtown, Allentown, Pennington, Bordentown and the Washington Crossing area have older houses with chimneys that are part of their character. Matching mortar and brick is worth the extra care.
If the house is in a historic district such as Mill Hill in Trenton, ask whether visible exterior changes may need review before the work begins. The slate and historic roof repair page covers more of that ground.
Should I remove a chimney I no longer use?
Sometimes, and it removes a leak point permanently. But taking down a chimney is structural work, involves the interior and exterior, and may need a permit. A roofer or mason can explain the options, and a structural professional should be consulted for a chimney that supports anything.
A capped, unused chimney can stay in place, and a proper cap keeps water out of the flue. Removal above the roofline is a common compromise, with the roof closed over the opening.
Ask for a written scope that covers the roof, the walls and the interior, so no gap is left between trades.
What does a cricket do, and does my chimney need one?
A cricket, also called a saddle, is a small peaked roof built behind a chimney to split the water running down the slope and send it around both sides. A wide chimney without one lets water and debris pile up on its uphill face. Roofers often recommend adding one when re-flashing a broad stack.
Think of the chimney as a dam in a stream. Water coming off the roof above it has nowhere to go but sideways, and without a cricket it pools on the uphill side, where the flashing is under the most strain. Leaves and snow collect there too, holding moisture against the joint.
A cricket is built from framing covered in the same roofing material, and it is flashed into the chimney and the main roof. It is a modest piece of work that makes a large difference on a wide stack, and it is cheaper to build while the flashing is being replaced than as a separate job.
Not every chimney needs one. Narrow stacks, or those on the ridge where water does not flow against them, may do without. The roofer should explain why they are recommending one for your chimney and show you where it will sit.
