subject: My Chimney Is New! Why Is It Cracking? [print this page] New chimneys come about from either building a new home or reconstructing your chimney. Unfortunately, cracks can come about on new chimneys just as easily as older chimneys, and this can be aggravating for homeowners. No matter what the reason for your cracked brick, it is imperative to deal with these before water damage occurs from freezing and thawing through the winter months.
What caused this to occur? Even if the chimney is brand new, using brand new brick and mortar, there are various reasons why a chimney would crack. It is important to distinguish between hairline cracks and long cracks that appear to just keep growing. After being laid, brick will shrink from UV exposure and the loss of small amounts of moisture present in brick. This may cause hairline cracks to appear, and although they are not of particular concern, you will want to consider sealing them with a brick sealant.
On the other hand, vertical or horizontal long cracks that are noticeably wider than what could be considered a hairline crack are definitely of an issue. These will need to be dealt with either by you or a professional. Often times the soil on which the chimney was built is not strong enough to support the thousands of pounds that now rest on it. Due to this fact the ground will shift. This process is considered "settling" and is the cause of cracks in a structure as it bends ever so slightly this way or that. The settling process can be expected to stop eventually.
On other occasions, it may be a footer that was built wrong that is to blame. This slab of concrete is supporting an extreme weight. Your footer must be at least 12 inches thick and extend 15 inches in all directions on the sides of the base of the chimney. Steel bars should be placed 2 to 4 inches up from the bottom of the chimney in both directions for additional support. If the chimney is not placed on a sound foundation, then there can be little hope for a structurally sound chimney. If the footer was constructed improperly, then the mason who laid this may be to blame and it would be prudent to have another company out to take a look.
Interestingly enough, mortar does not come to its full strength until it cures completely, a process that can take months in some cases. Strong gusts of wind can cause the chimney to move minutely in any direct, making the brick and mortar bend at an unnatural angle. As the structure is bent, cracks can occur. The most sound chimney will encompass steel bars that help to keep the chimney as upright as possible, even during the strongest winds, to prevent the brick and mortar alike from shifting until the mortar has time to cure completely.
Despite the cause of the cracks, you must remember that without proper care they will continue to deepen and worsen if they are not sealed properly. It is imperative to seal your brick with a sealant that will not only protect the crack itself from water penetration and freeze-thaw damage, but also allow the brick beneath it to breathe. Certain crack sealants are better than others, and doing a bit of research prior to making a purchase will save you trouble in the future. If you hire a professional to help you out, make sure to inquire as to what type of sealant they will be using on your chimney. Taking the time to read reviews on products and coming to a working understanding of what type of chemicals the product is comprised of will let you rest knowing that your chimney has been taken care of with prime products.
