Crack masonry

Remember, all cracks must be examined. More often than not, the primary cause of cracking in masonry buildings falls into one of the following three categories: movements, overloading, and material failure. It is not a secret that cracks are often caused, in different ways, by movements. In this case, the presence of cracks is an indication that the building has, at some time, been subjected to an imposed movement from the external environment, such as ground movement or thermal movement.

Ground movements are often caused by changes in moisture content of the soil around the perimeter of the foundation, poorly compacted fill, adjacent excavations, tree roots, etc. Thermal movements are caused by the response of a given material to thermal fluctuations over time.

When masonry is exposed to increasing temperatures — think about a south-facing wall getting warmer during the day — it expands. On the other hand, exposure to decreasing temperatures will result in contraction. When exterior masonry is exposed to hot-cold temperature cycles over time, it expands and contracts.

Construction materials can also move on their own due to their physical properties. Shrinkage, which in simple words is the contraction over time of cement-based products, affects concrete masonry blocks, mortar, and grout. On the other hand, clay brick expands irreversibly over time.

Since thermal movements and shrinkage cannot be fully prevented from happening in masonry buildings, designers try to accommodate movements and control cracking by using control joints, expansion joints, and joint reinforcement. When structural elements are subjected to more load than they can handle, they will crack due to overloading.

These cracks should be taken very seriously as they can result in structural instability and collapse if the overloading issue is not addressed. Have an engineer evaluate your masonry crack to determine if it is caused by structural overload.

Figure 2. Cracks in masonry parapet due to differential movement between clay brick, which expands over time, and concrete, which experiences shrinkage over time. Corrosion of embedded metal in masonry, such as wall ties, joint reinforcement, structural steel, lintels, etc.

This formation could be due to the weaknesses in the motor paste or strong bricks having the capacity more than the mortar. Initially, hairline cracks will appear as thermal cracks and they further developed up to 0.

Further, these types of cracks will reappear even after they rectified if the thermal movement in the wall is not stoped. These types of cracks occur due to thermal effects. Differential stresses caused due to thermal effects crack the brick. Clayey soils that subjected shrinkage movement causes these types of cracks in the walls. When these types of soils are dry, their volume reduces and it leads to the settlement of the part of the structure.

The horizontal slot, normally the mortar bed, can be cut using a twin diamond blade chaser with vacuum attachment, an angle grinder or a mortar chisel. All mortar must be removed, together with any loose debris, to ensure a sound bond.

Prepare the slot with HeliPrimer WB or thoroughly wet the slot with clean water. HeliBond grout is the recommended bonding agent. PolyPlus resin is used for smaller jobs and where loads are to be rapidly applied. Since the installation of these joints is a technical issue that affects the integrity of your project, the engineer should determine how to set them up.

You will need to install horizontal expansion joints if a shelf angle supports the weight of the brick. As an alternative to vertical expansion joints, you must place horizontal expansion joints underneath the shelf angle.

Before installation, remember to remove the temporary shims used to put the edge in position during construction. The joint will resemble the mortar, so finish it properly to allow greater structural quality and to reduce cracks from weak bricks.

The natural movements of the masonry and frame will determine the required size of the expansion. Consider the surrounding climate and the irrigation systems in place to find out how much space you should include in between the joints. The frame will move as a result of the deflections of the shelf angle, rotating the horizontal leg, and accommodating temperature change and shrinkage.

These alternatives to shelf angles must allow independent vertical movement between the blocks and the backing, which gives the brick veneer lateral support.

Besides dry shrinkage, changes in temperature and carbonation, some of the other factors that can also cause damage include:. Masonry consists of any products made of stone, clay or calcium silicate. The cause of cracking and the movement characteristics of masonry depends on the specific building material:.

Locate A Dealer. Depending on the type of building project, the multiple parts of your development may experience cracks over the years. The presence or absence of moisture in masonry will affect its movement and integrity. Once a porous masonry product sets, it expands as moisture content increases, resulting in the expansion of salts, and shrinks as it dries, resulting in drying shrinkage.

Excessive moisture could also cause corrosion in an iron or steel reinforcement in the walls. Condensation is a threat to walls and foundations. To maintain the structural integrity of your construction process, you need to practice healthy moisture control habits for masonry. Moisture management consists of various building practices to prevent moisture, including planning proper drainage surrounding the structure. The movement of masonry depends on temperature change.

Between fluctuations in temperature and variations of moisture in the air, the blocks of construction will expand or contract over time. Harsh weather conditions and seismic activity could also affect the movement of your masonry structure. In the winter, your masonry work is vulnerable to the freeze-thaw process. When water seeps into cracks in the blocks, it freezes overnight and expands. This expansion puts stress on the bricks and causes breaks, increasing the size of any existing fracture.

You can guard against freeze-thaw by using deicing chemicals and applying a sealant. While masonry work can last for centuries, cracks are common as a result of moisture buildup and temperature change. You should take these precautions to avoid the deterioration of your structure. Improper masonry installation may result in fractures or more severe foundation issues over several years. Start your new construction project the right way to prevent damage in the future.

Keep these tips in mind as you install your mason structure:.