Cracks in basement walls and floors are among the most commonly found types of structural distress in buildings, especially houses. However, many homeowners do not know whether the cracks in their basement are problematic, if they are aware of them at all.
To understand why cracks form, you must first understand that structures and their components move. They compress, extend and bend under applied load. There are also forces internal to elements of structures resulting from the behavior of the material or how the element was made. Most structural materials expand with increased heat and moisture and contract in cold and dry conditions. In addition, Portland cement-based materials, like concrete, concrete masonry and certain types of mortar, shrink as they cure. Cracks occur when a structural element made of a brittle material is subjected to an external or internal force greater than its strength.