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When should I be worried about foundation cracks?

Table of Contents

Any serious issue with the foundation can cause the whole building to tumble or suffer a similar major disaster. So, it is normal to worry when you notice foundation cracks.

But not all foundation cracks are a cause for alarm. There are two types of foundation cracks and while one only affects the aesthetics of the building, the other can damage the structural integrity of the building.

Types of foundation cracks

The two primary types of foundation cracks; Structural and Non-structural cracks.

Structural Cracks

Structural cracks are cracks due to foundation movement and can easily cause damage to the building if not repaired on time.

When to Worry About Structural Cracks

Since structural cracks are the cracks to look out for, here are key signs that require you to speak to a professional about the cracks. When you see

  • Cracks that are wider than 0.1 inches
  • Cracks are wider at one end than the other
  • Cracks keep getting bigger and wider over time
  • Stair step cracks along the brickwork
  • Horizontal cracks
  • Several vertical cracks beside each other
  • Wide diagonal cracks
  • Cracks that go from the ceiling down to a wall

Non-structural cracks

Non-structural cracks are primarily caused by concrete shrinkage or soil movement due to different reasons. But they do not pose any threat to the building’s structural integrity. But this does not mean non-structural cracks are completely harmless. In some instances, non-structural can cause wall cracks, thereby letting water seep into the basement or building.

When to Worry About Non-structural cracks

You should worry about non-structural cracks when:

  • Cracks with a width less than 0.1 inches get wider (it might be structural)
  • There is a single vertical crack (which means it is not structural) from where water seeps into your basement floor. You will need a professional to check it so that it does not lead to a weak foundation.
  • A crack in a block becomes multiple which extends to other concrete blocks. (this can indicate structural cracks.)

Causes of Cracks

Structural and non-structural foundation cracks can be a result of several things, and here are some of these reasons.

Tree roots

Contrary to what many think; the root’s growth pushing up the foundation is not what causes foundation damage. Rather, with the roots sourcing water from the soil through transpiration, the soil keeps drying up. After a while, the soil compacts, causing the downward settlement of the foundation. Thereby leading to structural foundation cracks.

However, having a tree near your home does not automatically lead to structural damage, but depending on the size and strength of the tree, it can easily lead to structural damage.


As time goes on, the foundation built centuries ago gets weaker. And it will most likely contain some substances referred to as substandard material. However, foundation repair might not be easy or feasible for cracks due to the issue.


A foundation settling might lead to cracks forming, causing structural foundation cracks.

Expanding soils

Your land’s soil type might cause issues if not well maintained before the house is built on it. Soils with high clay content can cause pressure on the land, heaving, and the like. This will lead to compacted soil as time goes on causing harmful foundation cracks.

Water leak

Whether due to poor drainage or leaking pipes, if water keeps seeping through or around the foundations, it will cause great damage in the future.

Poor soil compaction.

During the building process, if the soil was not properly compacted, it might cause the foundation to crack or drop-down after the house has been built. This is because the soil will no longer be able to support the foundation’s weight making it shift to the compacted sides.

Bad Engineering or Construction

If the engineers do not properly size the soil type, foundation load, and other essential factors, they might allow construction that is not suitable for the soil. Also, when the Construction Engineer adds more stories to the house than the one the foundation was prepared for, the building’s weight will weigh down the foundation posing a serious threat to the building.

Climate change

Cold climates might cause the ground to freeze. And as it freezes and melts, it can cause damage to the basement foundations causing more cracks over time.

Geotechnical issues

When earthquakes, landslides, sinkholes, and similar issues occur, they might cause cracks and serious structural problems to the building.


Whether harmful or not, you should take note of cracks or any abnormality in your building’s structure. And you should involve a professional for recommendation and repair.