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What is Foundation Heave (Signs, Causes, & How to Fix)

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Foundation heave can prove a remarkably traumatic experience for a mortgagee with unsightly cracks riddled into walls, doors that require brute strength to budge, and a triangle busting out of your garage slab, a sort of half-baked pentagram from hell.

Or, perhaps there is a bizarre swelling in the middle of your living room, a carpeted hairy tumor, a tripping landmine for poor G-ma. 

The crux of the matter is: foundation heave is ugly, can get in your way, and (worst of all), it damages your foundation and jeopardizes the structural integrity of your home.  

Now, here at Dalinghaus Construction Inc. we talk extensively about foundation settlement – what it is, why it happens, and how to fix it through the implementation of Push Piers or Helical Piers (both backed by our new Steel Pier Systems Lifetime Warranty).

Note – we love foundation repair so much, our content manager created a Dalinghaus jingle after hours on his piano after a few glasses of vino – entirely unusable, but entertaining and proof foundation repair is in our hearts.  

We eat, sleep, and breathe foundation settlement for two primary reasons:

  1. We are based out of Southern California and AZ where foundation settlement is the primary foundational issue.
  2. We see you, our readers and clients, as the heroes of your own story.

    The more information you have about your enemy (foundation settlement) and the treatment options (Push Piers, Helical Piers, Polyurethane Injection and Helical Tiebacks) the better, more educated choices you can make.

    We are here to educate. To guide. To facilitate. Then send you happily on your way to face the next challenge, your home’s foundation (one of your greatest financial and familial assets) safely secure.

However, there is another potential enemy of your foundation that we here at Dalinghaus need to address because there is a huge amount of misinformation about foundation heave. We need to set the record straight.

So, in the name of your education-in-all-things-foundation, this article will cover:

  1. What is Foundation Heave 
  2. Signs of Foundation Heave
  3. Causes of Foundation Heave
  4. How to address foundation heave the appropriate way   

So, let us begin dissecting this geological nightmare –

What is Foundation Heave?   

What is foundation heave? 

Foundation heave is the uplift, elevation of a foundation precipitated by soaked, expanding soils and can generally be attributed to a seasonal increase in moisture, a plumbing leak, or underground aquifers. 

 In summary: foundation heave lifts your home up. Foundation settlement takes your home down.

So, our two primary enemies are an upper and a downer (if you were a teenager in the sixties you know what we’re talking about).

Although in many ways foundation heave and foundation settlement are seen as direct, polar opposites – many of their signs and symptoms are the same.  

Foundation heave can affect any part of your home, regardless of what kind of foundation you have. However, foundation heave is especially noticeable in slab on grade foundations.

Slab on grade foundations are only 4 to 6 inches thick (comparably light, commanding less weight resistance against upward force), potentially creating a very nasty topographical road map beneath your feet.  

Old Construction Nursery Rhyme Circa 1909 – though we trip and trail, home heave will never prevail. As sure as the stars shine by night, helical piers can make it right.

 Signs of Foundation Heave

Now, it’s important to remember that this wet, expansive soil is working very hard to lift your home up. Turns out, your home was built to stay put. 

This is what happens when a fairly unstoppable force meets a very movable object.

The soil moves up, causing the foundation to move up (and not in a particularly uniform fashion), causing stress and pressure on the wooden bones of the house tucked away behind drywall and or tile.

This causes cosmetic and structural damage:

  •   Cracked drywall, brickwork, doorframes, and window frames
  •   Window/doorframes become out of square, causing sticky doors and windows  
  •   Lifted sidewalks, patios, and garden sheds
  •   Tilted/askew slab sections
  •   Cracks in slab
  •   Slab cracks joining together to form a triangle (supposedly, Lucifer’s favorite shape)

Note – the triangle/loop crack is the apex of the heave, meaning this tends to happen where the heave is the greatest.   

Now, these signs and symptoms are more than slightly annoying – they can interfere with the functionality of the home and impede quality of life. So, what causes it?

 Causes of Foundation Heave

 The root of the issue is occasionally roots – gnarled, wooden fingers creeping below patios and forcing the concrete up. But, the numero uno cause of heave is moisture – whether it be from weather, aquifers, or a pipe leak.

For example, let’s say it’s a sweltering Tuesday afternoon in August and it has been a dry summer.

Dry enough creeks have dried up and lakes have lowered considerably.

A thunderstorm rolls in and dumps buckets of rain onto the earth. It rains for several days.

The dirt, especially clay soils, that had been thirsty, begins to e x p a n d. When soil expands, it expands where there is the least amount of pressure.

Turns out dirt has other dirt to the left, right, forward, behind, and below. Leaving nowhere to go but up! 

So, this soil expands upward, a thirsty sponge soaking up all the water it possibly can, causing your home to go up.

Frost is also a notorious culprit when it comes to foundation heave, it’s double trouble. Imagine the clay is already soaked and it freezes overnight.

Water, when frozen, can expand by 9%. So, we already have expanded soil, expanding more due to frost, causing your house to stand on its tippy-toes. This is no beuno.  

In short, while water is the primary cause, it takes two to tango. Water and expansive soil combined equals an expensive mess.

Expansive soils create more financial loss in the United States of America than floodsearthquakestornadoes, and hurricanes combined. 

Fun Facts with Brian:  For classification purposes, soils fit broadly into two primary categories: expansive soil and less expansive soil. A short list of expansive soil includes montmorillonite, illite, and kaolinite (and, no, that’s not a list of forgotten Old Testament Hebrew Tribes).

Soil Map America (Dalinghaus) (1)

Over 50 percent of these areas are underlain by soils with abundant clays of high swelling potential.
Less than 50 percent of these areas are underlain by soils with clays of high swelling potential.
Over 50 percent of these areas are underlain by soils with abundant clays of slight to moderate swelling potential.
Less than 50 percent of these areas are underlain by soils with abundant clays of slight to moderate swelling potential.
These areas are underlain by soils with little to no clays with swelling potential.
Data insufficient to indicate the clay content or the swelling potential of soils.

There are many different reasons why additional moisture might find its way below your foundation. 

Common causes of heave include:

  •   A change in the water table level
  •   Busted drains or water-runoff from construction
  •   Frost and or water absorption expanding subsoil

Note – one secondary reason for excess moisture in expanding soil is when trees or vegetation have been removed or died and are, thus, no longer absorbing large amounts of water up through their root systems. 

Therefore, water accumulates, as it is no longer being utilized by previous vegetation.  

Ah, I know what you’re thinking. As the hero of your own story, you’re already trying to figure out how to deal with this foe.

You probably have guessed the easiest way to get foundation heave under control is to control the moisture level underneath and around your foundation.

And, that is correct, but it’s not simple.  

How to Address Foundation Heave the Appropriate Way   

There are a lot of magic beans, emperor’s clothes, and Uncle Ricos peddling allegorical herbal enhancements in construction.

Some construction companies have devised some incredibly idiotic means of treating foundation heave. 

Dumb Idea Number 1: Just Keep it Wet

 Yeah, you read that right. The first idea is to keep the subsoil around your home the same level of soaked all the time at just the right amount.

The idea being it won’t go up. Won’t go down. It will be just right.  Our foundation inspection expert Garrett Batten refers to this idiotic idea as:  

  •   Temporary (what are you going to do, water your home’s foundation forever?)  
  •   Fluctuating (you will have to constantly readjust how much water depending on weather)
  •   You Pay for it Every Day (your water bill will skyrocket)   

Do not pay someone to put sprinklers beneath your foundation around your home’s footing. This is not a solution, this is a Gilligan gaff. 

Dumb Idea Number 2: Just Keep it Dry  

The idea here is to drill down beneath your foundation, create a void, fill the hole with a hollow pipe, hook that pipe up to a fan, and let that fan keep the soil below your foundation dry.

Yes – good luck keeping the ground beneath your foundation dry with a fan put up in your attic with plastic pipe reaching down into your foundation.

We don’t heat or cool the great outdoors, don’t give your dirt a fan either.

Do not pay someone to drill a hole in your foundation to fan your dirt.

Dumb Idea Number 3: Hire a Shaman

If you want to give some guy a hundred bucks to keep it from raining – you do you, man.

The Correct Approach  

Helical Piers are actually the best approach when it comes to securing your home against foundational heave.

Helical Piers stop your home from settling and from uplifting because the piers are locked together.

Note: Push Piers are not locked together, they simply fit into another. So, if there is any uplift, the Push Piers can become unlinked.

Helical Piers will keep your house in place. 

Although, there is that rare occasion where once the helical piers are in place, the earth still lifts making the heave worse because something’s gotta give and it will be your home’s foundation, not the earth.

Mother nature wins most battles.  

That’s why it is also imperative to properly route water/moisture away from your home’s foundation to help prevent the expansive soil from receiving moisture. 

Rain gutters, proper drainage, and proper grading of all surface soils around the home’s perimeter help prevent water from pooling near the home.  

Don’t Wear the Emperor’s Clothing 

There are a lot of slick foundation salesmen out there who would love to water your foundation, fan your dirt, or perform an anti-rain dance. You need to be wise and wisdom comes through education. 

Now, you are educated on what exactly foundation heave is, the signs & symptoms, the causes, and how to treat it.

You should feel very accomplished, having this specialized knowledge in our niche industry. 

For our out-of-state readership. We appreciate you. Keep reading our blog

If you abide south of Southern California’s grapevine or hangout in sunny AZ and need a foundation inspection, click on our link below for a FREE foundation inspection –


Brian Dalinghaus

Brian is one of the Co-Founders of Dalinghaus Construction. He has been in the foundation repair industry since 2005. During his career, he has been associated with helping over 4,000 homes and structures throughout California and Arizona.

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