Why Do Homes Sink?

Why Do Homes Sink?

My name is Mark Cook, and I have been working in the foundation repair business for nine years.  Before that I worked for my dad who is a Civil Engineer, doing land surveying and computer drafting.  

My approach when I look at homes that I am inspecting for foundation repair is the same as what I did when I was a land surveyor.  I would do a lot of topographies on land across Southern California. When I inspect a residence, I take elevations and treat it like I’m doing a topography.  

I utilize a Technidea Zip Level to take elevations around the residence to measure elevation changes.  Many of my customers ask me, “what are you looking for with that machine”? I always answer their questions the same way.  

“I am taking measurements throughout your residence seeing the elevation difference.  An engineer’s standard of a level home is that they don’t want the elevations to drop more than 0.5” within 10’  So I am looking for elevations that are out of standard.” 

I always tell people that many of the homes that I measure and give proposals to fix the residence are out of level over 1” to 2”.  Some are out of level 3” and 4” and I am even doing a job for a home improvement reality show in San Clemente, CA that is out of level 10”! 10” is a major drop and we are hoping to get 7” to 8” of recovery on it.

Why do homes sink? 

This question comes up every week.  And there are a few answers that I give to people.  One of the main reasons homes sink is when they were built, they didn’t compact the dirt enough underneath the residence.  The standards were completely different in the 1960’s than they are today. 

Another reason homes settle is that they have improper drainage.  When I worked for my dad’s civil engineering company I learned that the dirt next to a home needs to slope 2% away from the foundation.  This makes it so when it rains the water flows away from the house. Just about every lead I go to, the dirt next to the home is either flat or sloping towards the house.  So it makes sense if the water is sitting next to the foundation and saturating under the heavy footing then the home will settle in those areas.

Homes also settle because of the expansive clay soils underneath.  Southern California is notorious for having expansive soils. It’s also notorious for having up and down climates as far as being very dry for long periods of time, where the soil dries out immensely and then having long periods of wet weather where the soil will expand.  

Imagine having a concrete slab home and having this type of variable underneath it. You can easily see how this causes cracks throughout the home.

Ultimately I tell all of my customers that there is more than likely a combination of things that causes homes to settle ranging from the things I mentioned above as well as slope movement, earth movement and poor construction.

If you are having foundation problems at your residence, feel free to reach out to Dalinghaus Construction and ask for myself or one of our other experts to come and give a free foundation inspection.


Mark Cook

Mark Cook is a veteran foundation repair inspector with over 11 years of industry experience and 4,000 repair projects completed. Mark learned the tools of the trade from his father, Craig Cook, a celebrated Southern California Civil Engineer in the business since 1980 and a stickler to detail. Mark learned land surveying/development and CAD at his father’s construction company from 2000 to 2010 before transitioning to foundation repair.

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