Cause: Differentialsettlement— one section of thefoundationissettlingmore than an adjacent section. The uneven downward movement creates shear stress in thewall, and shearcrackspropagate at approximately 45 degrees (following the principal stress trajectory).
WhenFoundationCracksIndicate a Problem. One of the most noticeable signs offoundationsettlementis visiblecracksinyourfoundationwalls. However, not allfoundationwallcracksare bad - some are even normal.
Concretewallscancrackas they cure. This is normal and is nocausefor alarm. However,foundationwallscrackingdue tofoundationsettlementissues or expansive soils may require some repair work.
If you see a horizontalwallcrack, then it’s time to ask an expert for an evaluation. Horizontalcracksindrywall could be a bigger issue; they are usuallycausedbyunevenfoundationsettlingor a water drainage issue.
Foundationsettlingmaycausemany problems. For example, jammed windows and doors, water intrusion,crackingof masonry work, and other possible defects. But, if the homeowner acts quickly at the first signs ofsettling, damage can be drastically reduced.
This particular example perfectly highlights why Cracks In Foundation Walls Caused By Settlement is so captivating.
CommonCausesofFoundationCracks. Understanding the rootcauseis key to determining severity:FoundationSettlement: Uneven soil compaction cancausefoundationsto shift, resulting in diagonal or horizontalcracks, misaligned doors, or windows.
Shrinkage: Minor surface levelcrackscausedbyshrinkage of concrete. but should be monitored for growth.Settlement: Mediumcrackscausedwhen the ground belowsettles, high priority for repair. Structuralcracks: Large more serious concretecracks, high priority for repair.
A typicalcauseof diagonal or "step"crackingina concrete blockwall(and some brick or other CMUwalls) is frost heave orsettlement, but as you can see in the photo above, a collapsing masonry blockfoundationmay also show diagonalcrackingnearwallcorners.
