The main part of chimney masonry is chimney mortar. The mortar is made up of clay particles and hard-packed aggregate (ASA). These are then held together with a chemical binder. These chimney products can be called mortar, slurry, and spatter. It acts as a layer of waterproofing that prevents water from entering the structure’s interior. Improper installation of chimney masonry can result in crumbling mortar, weakened mortar joints, crumbling fluting, or cracked and failing chimney tiles.
How to Repair Cracks in Chimney Masonry
Two types of mortar most often found in masonry chimneys are hard mortar and soft mortar. Hard mortar consists of finely ground clay and granular stone dust, and it is typically applied to the inside wall and inside buttresses. Soft mortar is generally made from coarse sand and epoxy resins and is applied to both sides of the flue. Both are commonly mixed with water. Both are mixed with water, which is a method of decreasing the likelihood of mortar separation.
“Wear and Tear”
The weakening or dissolution of mortar-clay particles can lead to a host of issues. These issues are generally referred as “deterioration” or “dismiss”. Usually, the problem will begin at one end of the flue and then spread to the rest of the structure. In some cases, this process may go unnoticed until it is too late. When masonry chimney repair becomes necessary, one should contact a licensed contractor who is experienced in this industry and can prevent serious structural damage from occurring.
Cracking
It is common for a chimney or masonry structure to crack or become unsafe. The bricks or tiles may break away from the masonry wall and fly off into the air. For this reason, new mortar joint installation is necessary. A new mortar joint might be necessary if the mortar is cracked, damaged or weakened by water, weathering or any other factor.
Other Issues
A chimney’s condition can be affected by external factors. For example, a building can become wet from rain, which can make bricks or tiles swell and move out of position. Strong winds can cause large sheets or ice to form. High humidity levels are often blamed for mildew and mold growth in damp, humid environments such as chimneys. These external factors must be considered and properly resolved before masonry chimneys can safely be used again.
There are two approaches to addressing the problem. The first is to fix cracks in the fireplace’s masonry. The second is to replace damaged bricks. Brickwork can be expensive, so it may make more sense to fix the mortar joints than replace the whole chimney. A repair job can often be enough and the whole fireplace need not be replaced.
There are several important things to do before any mortar joint repairs can be made. It is necessary to address cracks within the brickwork. A flue or liner may also be required depending on what type of crack you have. This will prevent any further damage. Cracks in mortar between bricks or tiles may not pose a threat until they develop a larger diameter and begin to expand. Once they have developed a size large enough to interfere with combustion, they are no longer safe and should be repaired.
The main problem with cracks or deterioration of mortar chimneys is their location. A chimney should be placed in an area of your home that is warm and comfortable, especially during summer. This means bricks may expand and contract when temperatures climb above or below a certain point, creating cracks in the mortar. Unfortunately, the crack may not be noticed until it becomes large enough to allow air to travel under the flue to the inside of the house. At this time, it may be too late to repair the crack and the damage it causes will not only reduce the efficiency of your chimney, but could pose a health risk to you and your family.