Chimney Crown and Crack Repair in Bridgewater, NJ

A crack in the crown or a mortar joint is usually a water problem first and a safety problem later, but a crack that goes through the flue tile or runs through the stack is a safety problem now. Hairlines in the top slab let in rain and little else. They matter because of what water does next: it soaks the brick, rusts the damper, and every freeze pries the opening wider.

The cracks to take seriously are the ones that show movement. A crack wider at one end than the other, a step pattern climbing the joints, bricks that rock when pressed, or a stack that no longer lines up with the roof all suggest the masonry has shifted. So does a cracked flue tile, which lets exhaust reach the brick around it. Stop using the fireplace, and any furnace or water heater on that flue, until someone has looked. Keep a working carbon monoxide alarm near the bedrooms in any house with a chimney in use.

On a first-wave house the crack is usually in the crown or the top few joints, because that masonry is the most exposed and was rarely built with an overhang. In Finderne, Bradley Gardens and the older streets of Green Brook, a typical stack has a mortar top sloped by hand and sitting flush with the brick, so each storm wets the face of the chimney and the joints below it. Those joints go next, on the side that takes the most weather.

On a Victorian in North Plainfield or an older house in the Basking Ridge historic district, the chimney is taller and carries more than one flue, and the trouble often sits in the courses above the roofline. Tall stacks catch more wind and dry unevenly. Newer houses in Warren, Bernards and Bedminster often have no masonry top at all: the fireplace uses a metal pipe in a framed chase, so a crack there means a rusted chase cover or split siding, and that is chimney repair of a different kind.

A crown with fine cracks and a sound body is sealed with a flexible crown sealer, while one that is breaking up is taken off and formed again. Roof cement and hardware store caulk do not count as repairs here, because they harden, shrink and hold water against the masonry. Sealing works where the slab underneath still holds together. Once pieces move under a hand, the slab has finished its working life and a coating only hides that.

A new crown is built to shed water: sloped away from the flue and overhanging the brick so drips fall clear of the face. New Jersey's code wants a drip edge on that slab plus a caulked joint, called a bond break, where it meets each flue liner, and ASTM C1283, the standard it points to, sets an overhang of at least 2 inches and a thickness of at least 2 inches. That bond break is a detail older masons skipped. A crown set hard against the tile cracks there first, because tile and concrete grow and shrink at different rates. A chimney cap fitted at the same time keeps the flue itself dry.

Yes, in most cases, by repointing only the joints that have failed. Loose mortar is ground out to a sound depth, fresh mortar is packed in and tooled to match, and bricks with popped faces are replaced one at a time. Often only the top few feet need it, since mortar on a stack crumbles from the top down.

Older brick wants a softer mix. National Park Service guidance on repointing historic masonry says the new mortar should be softer than the brick and no harder than the old mortar, because a joint is supposed to take the movement and a hard joint passes that stress into the brick. On a Washington Park house, or anything else built before modern portland cement mixes were common, a too-strong repair can start the spalling it was meant to stop. The crew aims to match the color of the existing joints too, so the work does not read as a patch from the street. If a historic review applies to the house, say so at the start.

A crack that keeps coming back usually means the patch covered the symptom while the cause kept working. A skim of mortar over a crown bonds poorly and pops off in a season or two. A crack sealed tight against a flue tile reopens the first cold night, as the tile moves. Water that is still getting in behind the patch, through a joint higher up or a missing cap, freezes and pushes it off from the back.

That is why a repair here begins at the cap and follows the chimney all the way down to the firebox. You see photographs of what the crew found, and each repair is listed separately, so you can tell the crack from whatever is feeding it. If rotted decking turns up around the stack, the estimate marks it as roofing work for a roofer. There is no charge for the estimate. Crack and crown calls go to a veteran owned company, licensed and insured as NJ HIC 13VH13654300, 8 AM to 8 PM, 7 days a week. Mortar and crown work suit late spring through early fall, while a leak that cannot wait is handled around the weather. If the top of the stack has moved, read about a chimney rebuild next.