Chimneys 101:
A damaged chimney can be a serious problem for a home. Water can get in around your chimney and ruin the wooden structure of the roof. The mortar and bricks can crack or spall, and become weak. And if not sealed right, the chimney will soak up water, which will freeze in the winter and cause it to crack.
What's more, if bricks become loose, they can fall and injure people and property.
However, a properly built chimney, if properly maintained, can easily outlast the house around it.
Here are some tips about what to look for in a quality chimney, and how to know when it is time to get it repaired.
A damaged chimney can be a serious problem for a home. Water can get in around your chimney and ruin the wooden structure of the roof. The mortar and bricks can crack or spall, and become weak. And if not sealed right, the chimney will soak up water, which will freeze in the winter and cause it to crack.
What's more, if bricks become loose, they can fall and injure people and property.
However, a properly built chimney, if properly maintained, can easily outlast the house around it.
Here are some tips about what to look for in a quality chimney, and how to know when it is time to get it repaired.
Anatomy of a Chimney:
Flue - This is the inner part of your chimney. The flue is like a pipe, and when it works right, all the smoke stays in the flue till it comes out the top of the chimney. Some chimneys have more than one flue.
Block Core - This is a core of concrete blocks that protects the flue, and provides most of the structural strength of your chimney.
Outer Brick or Stone - This is the protective layer of brick or other masonry material that is specially designed to make a solid outer shell to protect the flue and core from weather, or anything else that might damage them.
Crown - The Crown, also called a "chimney cap," is a layer of concrete that makes a cap on top of the chimney so that water can't get into the top of the chimney. A good crown should overhang the sides of the chimney about 1-1/2 inches, and be three inches thick.
Rain Cap - This is the piece, usually made of metal, that covers the top of the flue. It keeps rain from falling down into the chimney, which can destroy it from the inside out, as well as keeping birds, squirrels, and other pests out.
Block Core - This is a core of concrete blocks that protects the flue, and provides most of the structural strength of your chimney.
Outer Brick or Stone - This is the protective layer of brick or other masonry material that is specially designed to make a solid outer shell to protect the flue and core from weather, or anything else that might damage them.
Crown - The Crown, also called a "chimney cap," is a layer of concrete that makes a cap on top of the chimney so that water can't get into the top of the chimney. A good crown should overhang the sides of the chimney about 1-1/2 inches, and be three inches thick.
Rain Cap - This is the piece, usually made of metal, that covers the top of the flue. It keeps rain from falling down into the chimney, which can destroy it from the inside out, as well as keeping birds, squirrels, and other pests out.
Common Chimney Problems
Spalling Brick is the most common evidence of a chimney that needs to be repaired. As seen in the picture to the left, the outer brick has been infiltrated by water, which has frozen and broken the bricks. This usually happens when the chimney is not sealed correctly, or the crown is cracked.
A Cracked Crown is often the cause of serious chimney problems. When the crown cracks, whether due to age, improper installation, or poor design, water gets into the tops of the bricks and inner core of the chimney. These parts are not designed to repel water, like the outside of the chimney is, and when they get wet, it immediately causes the chimney to deteriorate.
Deteriorated Mortar is a result of age, soft mortar, improper sealing and flashing, and our harsh Indiana weather. If the problem is caught soon enough, it is often possible to grind out the old mortar joints, and replace them without rebuilding the entire chimney. This process is called "tuck pointing." When we tuck point a chimney, we use type N mortar, the highest grade locally available.
Efflorescence occurs when salts wash through the bricks due to moisture flowing through the chimney, and then dry into crystals on the outside of the chimney. Chimneys showing efflorescence can often be repaired before more serious problems develop. We can usually find where water is entering the chimney, fix the problem, and then clean and re-seal the chimney without a major overhaul.