While chimneys are built with strength and durability in mind, it doesn’t mean they are immune to damage. Due to harsh weather conditions such as the freeze-thaw cycle, it’s not uncommon for cracks to appear in the bricks and gaps in the mortar joints over time. Lightning strikes and water leaks can also damage the brickwork. Immediate repairs are necessary to prevent further deterioration that can lead to a partial or complete chimney collapse.
Chimney tuckpointing or repointing is a restorative and cosmetic process that repairs the decaying mortar joints due to extreme weather conditions like the freeze-thaw cycle. A chimney mason will first clean out the gaps or holes in the mortar joint before filling it in with a waterproof bonding compound. The final process is color matching. The mason will expertly match the tuckpointing color to the remainder of the chimney giving it a handsome, like-new appearance. The repair strengthens the chimney and prevents further deterioration. Chimney tuckpointing is an option when the damage is caught early, the bricks are in good condition, and damage to the mortar joints is not extensive. Otherwise, a partial or complete chimney rebuilding may be necessary to restore the chimney.
When left unrepaired, the chimney can suffer extensive damage, especially when the bricks are cracking, crumbling, or separating from the chimney. Sometimes the damage is limited to a portion of the chimney such as the crown, roofline, or firebox.
For example, a lightning strike may damage the upper part of the chimney. Or a water leak may damage the firebox. In cases where damage is limited to a specific portion of the chimney, a partial rebuild is often recommended. During partial chimney rebuilding, the damaged section is removed and rebuilt with new bricks and mortar to meet local building codes. When rebuilding fireboxes, chimney masons will use firebrick, which has a higher heat resistance than the standard bricks used on the rest of the chimney. When chimney damage is limited to the roofline and flashing, roofline rebuilding is an option. It is often the next best option when the damage is too severe for tuckpointing, but a partial rebuild isn’t necessary.
However, when there is severe structural damage, the only option may be a complete chimney rebuild. A complete chimney rebuild requires the tearing down of the original chimney structure. Depending on its condition, the firebox, hearth, and smoke chamber may be salvageable and remain in place. The chimney structure is then completely rebuilt per local building codes. Once complete, the rebuilt chimney will perform safely for decades.
If it has been more than a year, it’s time to schedule a chimney inspection. Annual chimney inspections are the best way to avoid extensive repairs. However, if the chimney is already showing signs of wear, a chimney professional will recommend the best option for repair. The expert will evaluate the structure and determine whether tuckpointing, a partial or complete chimney rebuilding will be necessary to restore the chimney and mitigate any fire and safety risks.