Inspecting Concrete Block Foundation Cracks
Concrete block or “cinder block” foundations are very common. Other terms used to describe this foundation type are concrete masonry units (CMU’s), masonry blocks, or cement blocks.
Some common foundations problems homeowners experience with cinder block foundations include cracking, leaning, shifting, and bowing. Usually, a combination of two or more of these problems can be occurring at the same time and actually help to pinpoint the root cause of the problem. Having some knowledge of construction methods will also help.
Horizontal cracking often indicates some sort of outside pressure pushing in on the block, especially if the wall is also bowing. Sometimes the wall may also be leaning in from the top as a result of outside pressure, but not all of the time. Block walls can also shift horizontally toward the inside of the basement or crawl space. Usually this occurs on between the first and second rows from the bottom.
Another type of common crack in masonry block foundations is the stair step crack which runs along mortar joints. Trace this crack to the bottom and a crack in the footer may likely be found. At the very least, this type of crack indicates settling in the soils below the home. Vertical block foundation cracks, which run straight through the block, can be an indicator of extreme settling in the foundation. In rare cases, a minor vertical crack can just be from some shrinkage of the block. But this is very unlikely.
In some extreme cases, it seems that all of the above cracks are occurring at the same time, along with a heavy bow or bulge. Very strong pressure from outside can cause this and should be dealt with immediately. Your home is in serious danger.
In all cases, be sure to get a home inspection from a recommended foundation specialist at your earliest opportunity. We address different types of cracks along with possible solutions in other parts of this site. There is also helpful information in our free guide.
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