Foundation Wall Cracks - when do we need to worry? 1

[Alan CA]

Most of foundation walls show cracks, which might be shrinkage or parging issues. But what I see as a common practice as a reaction to seeing these cracks is "don't worry this is nothing"!
This happens almost all the time when I see a foundation wall being assessed. Mostly, it will be advised that the crack is filled to prevent water penetration.
So, how do we tell if we need to worry about a wall crack, and when not to worry?

 

[SlideRuleEra]

For sure if the foundations walls are moving relative to each other... time to find out why.
Movement may make take a while to determine, maybe a month, probably longer.
Sometimes movement can be discovered on the spot; I have encountered paint stretched like chewing gum across a crack - obviously the crack was getting wider.

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[oldestguy]

This 90 year old guy is scratching his head to see if he can recall a major failure with walls that became cracked AFTER the building was on them. Sure they looked pretty sad, even some were reinforced with stuff on the inside,etc., but still functioning. Usually the complaint was it may affect sale value. Only one actually was laid down inside the basement and that was due to jetting the fill in the garage. Failure before setting the building and backfilling did push some over.

 

[jayrod12]

In standard residential, straight vertical thin cracks are typically a sign of shrinkage and therefore can be ignored. Horizontal cracking or diagonal cracking are generally signs of overloading/lack of reinforcing(horizontal cracks) or differential movement (diagonal cracks) and should be investigated further.

 

[killswitchengage]

You need to know why , perhaps cracking of walls is due to foundation movements like soil settlement or heaving.