Cracking bricks is a cause for concern as they usually indicate a more serious problem with a wall structure. Although brick homes are generally solidly constructed, over time mortar used to hold bricks in place and occasionally the bricks themselves deteriorate. Once you determine what is causing your home's bricks to break, maintenance is likely required to restore your home to its original appearance and structural integrity.
Movement caused by settlement, expansion or destruction to a brick wall can cause its bricks to crack, especially if the mortar breaks and falls out. Soil conditions impact brick foundations as certain soil types can expand up to seven times their normal size from wet to dry, indicates Alamo Masonry Repair. When soil expands, it causes the foundation to move and puts pressure on bricks. If the movement is not uniform so that it affects the entire foundation equally, it can cause bricks to break in sections where the greatest movement occurs.
Extreme weather conditions, such as storms and floods, cause bricks to break. Hail, in particular, can cause bricks to chip. Heavy rains, strong winds and flooding can wear away mortar and leave bricks vulnerable to breakage. A brick also can break if moisture penetrates it, freezes and expands. Inspect your home's exterior every year to identify possible storm-related damage.
A high-powered sandblaster or water pressure washer is sometimes used on an exterior brick wall to remove paint, algae and dirt. Yet these cleaning and paint removal tactics can actually damage and deteriorate brick. Sandblasting and pressure washing strip away a brick's outside covering that it received when it was initially fired. Once the outside covering is removed, moisture enters the brick's interior and weakens it, eventually causing the brick to break. InspectAPedia suggests avoiding sandblasting for building renovation and maintenance projects involving brick as it's a bad practice.
If a brick wall has not been correctly caulked or if caulk exists in areas it should not, the bricks can break. For example, the steel lintel above a window or door should not be caulked because caulking it actually allows moisture to penetrate the steel and rust it. Moisture can invade the lintel through fissions and mortar joints in the brick's exterior. As the lintel corrodes, it swells and the expansion eventually causes nearby bricks to break.
Bricks Laid Right Against the Foundation
You can find up to a 16-inch crack in a diagonal line if bricks have been laid exactly in line with a concrete foundation, states Ask the Builder. The bricks expand and apply pressure to the foundation, which causes cracks to sometimes appear in interior walls. While these cracks do not signal any major structural damage, they can cause small breaks to occur in the bricks as the foundation does not provide enough room to accommodate the expansion. Unless the interior crack widens beyond a hairline, it's likely not worth attempting to repair it since it probably will reappear when outside temperatures rise again next year.