Are cracks in masonry brick or concrete block walls serious? The answer is yes and no. It depends on a number of factors including the number of cracks, size of the crack (length, width, depth), the impact it’s having on the bricks or blocks in their field including the direction they are heading. First, it’s important to understand what these bricks & blocks do.
Bricks – Today, the brickwork on homes is referred to as brick veneer. It’s not made of thin pieces of brick, rather a single width or row of non-load bearing brick that typically rests on, and is supported by, a poured concrete or masonry foundation wall system. As the brick is built up higher on the wall, metal straps (or ties) are anchored in the mortar and tied to the wood stud wall behind them providing lateral support. The bricks are used like an exterior cladding / siding on a home. Older homes were constructed using double-brick, brick & block or solid masonry construction. These bricks are placed in rows like the brick veneer with another layer behind them. They are joined together with metal ties or bricks turned ninety degrees (90O) to the two layers every so many courses. In this case, the double-brick construction forms a structural component of the building.
Concrete Blocks – Concrete blocks are commonly used for infill or structural purposes (such as a foundation wall), and installed in one layer / depth. The size of the block is determined based on the application. Some blocks are wider to carry heavier loads from above. Depending on the length of a concrete foundation wall, a buttress wall may be required on the inside basement wall to support the block wall from bowing inward. The concrete blocks are installed similar to brick, however as they are hollow they can be filled with concrete and or rebar for additional strength.
Types of Cracks – (1) Hair line cracks, or step cracks that follow the mortar joints of the brickwork, are often not serious.
(2) Cracks that are vertical and run directly through the bricks or blocks themselves may be a structural concern. If the cracks in the wall are “V” shaped, such that the opening of the crack is wider at the top or the bottom, it may be an indicator of a structural concern as well.
(3) Horizontal / lateral cracks are often thought to be a structural concern. Sometimes the wall will bow or buckle in along the horizontal crack. The horizontal mortar joint may appear like it is separating from the brick or block. Other times, the crack may be directly through the brick / block themselves.
(4) Cracks in bricks, blocks and or mortar joints that cause the brick / block to be out of plane with the rest of the wall may be can be a structural concern too.
It’s important to note that a crack can simply be an indicator of something which is afoot with your wall or foundation which has not fully presented itself yet. Sometimes, the crack may need to be monitored for movement. Learn more about monitoring a crack. In order for a crack to be “structural” or not in nature, it’s often referred to as being “live or dead”. This cannot be determined by just looking at it, so a professional should determine whether monitoring is appropriate in the circumstance.
Don’t ignore cracks in your brickwork or concrete blocks. Be proactive before it gets out of hand.