Chimney Repair

We’ve posted information about chimney crown repair, chimney swifts, and flue repair in previous entries, but what about the outside of your chimney? The brick or stone forming the surface of your chimney is subject to wear and tear over time, which shows up in a variety of ways:

The most common external chimney problem is damaged or degraded mortar joints between bricks. Constant exposure to the elements will wear down mortar joints over time, and they’ll need to be repointed or retucked (the extent of the repair needed will depend on just how much of the mortar has worn away). As with flue tiles, damaged external mortar joints allow water inside the structure of your chimney, putting you at risk of more serious (and costly) damage later.

A more serious issue comes when the bricks are spalled or cracked. Spalling is when water absorbed by the bricks freezes and causes them to flake and split, with layers coming off and falling away. Some bricks are more porous, and therefore more prone to spalling.

Exterior cracks can follow mortar joints in a lightning bolt pattern or crack bricks or stones in a vertical line. These cracks are the result of improper chimney construction, a chimney fire, the house foundation settling, or things like the earthquake that hit Virginia a few years ago. Repairing this type of damage can be as simple as replacing an individual brick or two, or can be a very involved rebuilding process, depending on the extent of the damage. A qualified chimney technician will be able to discuss the required repairs with you, and give you an idea of how much work is involved.

Once the needed repairs have been addressed, it’s time to take a look at prevention. In our post on chimney crown maintenance, we discuss both crown sealant and flue/chimney caps. For vertical chimney surfaces. clear sealants are available  to keep rain water from soaking into the brick of your chimney, while allowing water vapor to escape and keep the chimney dry. This seals mortar joints and cuts down on spalling.

It’s also important to take a look at your chimney flashing (the metal strip(s) overlapping the joint between your chimney and roof) to make sure it’s in good condition. Damaged or absent flashing will allow water to penetrate your home, no matter how well-sealed the masonry is.

It helps to schedule this work during the warmer months, while technicians’ schedules are more flexible and freezing weather won’t interrupt work. For more information, give us a call or fill out our online contact form today to speak with us about getting your chimney inspected, repaired if necessary, and ready for whatever weather comes your way!