Chimney Repointing and Spalled Brick Repair in New Jersey

Mortar is meant to wear out before the brick does. Over decades, rain washes it out and frost pries it loose, joint by joint, until water runs straight into the stack. Repointing means grinding out the failed mortar to a set depth and packing in new mortar, so the joints shed water again. Caught early, it is one of the least expensive ways to add decades to a chimney.

Spalling is the next stage. When brick soaks up water and that water freezes, the face of the brick pops off. New Jersey's inland suburbs see plenty of hard freezes; New Brunswick averages about 110 freezing nights a year (NOAA 1991-2020). Once a brick has spalled, it soaks up even more water, so the damage speeds up unless the brick is replaced.

Signs you need this

• Mortar joints sunken, sandy or missing
• Brick faces flaking or popping off
• Pieces of brick on the roof or in the gutter
• White powdery staining on the brick
• Damp patches on the chimney breast inside

How we do it

1. Map the damageAt the free inspection we mark which joints and bricks need work and photograph them.
2. Cut out old mortarFailed mortar is ground out to a consistent depth without damaging the brick edges.
3. Replace spalled brickDamaged bricks are cut out and replaced with brick matched to color and size.
4. Repoint and toolNew mortar is packed in and tooled to match the existing joints.

Why do older New Jersey chimneys need gentler mortar?

Many older homes in the state were built before 1940; the Census Bureau puts that share at about 59% in Montclair, 56% in Maplewood and 49% in Collingswood. Brick from that era is often softer than modern brick, and it was laid with softer, lime-rich mortar.

Repointing old brick with hard modern mortar can backfire. The mortar ends up stronger than the brick, so the brick takes the stress and spalls. On older chimneys we use a mortar suited to the brick, which lets water move through the joint rather than through the brick face.

Why are gas flue chimneys spalling from the inside out?

Gas heat is everywhere in New Jersey, and gas exhaust is full of water vapor. In a chimney that is too big or unlined for a modern furnace or water heater, that vapor cools and condenses inside the flue, soaking the masonry from within. White staining on the outside of the stack is often the first sign.

Repointing alone will not stop it. The flue usually needs a liner sized to the appliance, typically $625 to $2,250 for a furnace or water heater liner. We look at both the outside and the flue before recommending a fix.

Is it worth repointing a row home or twin chimney?

Usually yes, because the chimney is part of the wall you share. Camden has more than half its homes as row homes and Trenton over 40%, per the Census Bureau, and many of their chimneys straddle the party wall.

Water that gets into a shared stack can show up on either side. We tell you what we see on the neighbor's half and can quote the whole stack if both owners want to do it at once.