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3 Reasons to Void Fill after a Foundation Repair Lift

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So, Dalinghaus Construction Inc. has lifted your home back to maximum practical recovery via our push pier or helical pier systems (both of which are covered by our lifetime warranty) – now what?

Polyurethane foam injection is an imperativenon-negotiable step when it comes to slab foundation repair.   

We’ve had some customers ask if they really need polyurethane foam to fill the void underneath their home after a lift. The answer is always unequivocally yes.

Polyurethane Injection to void fill after a lift is important because:

  •   It eliminates space for critters (rodents, snakes, and neighborhood cats)
  •   It protects the home from rain and moisture
  •   It provides structural support (by far the single most important reason for application) 

Before we dive in, here is a Dalinghaus disclaimer that may save you some cold hard cash. It is important to note that if your contractor is simply stabilizing your foundation (that is, ensuring the foundation won’t sink any further) polyurethane void fill is not required.

Some shady contractors will push void fill for stabilization even though it’s not necessary. Why? More sweet moolah and cool jetskis in Cabo. 

Please also note – void fill is only helpful if there is a void

Polyurethane Void Fill Eliminates Space for Critters

One of the primary reasons to void fill after a foundation lift is to ensure there is no cozy cave for wildlife to move into.

While your daughter might be excited about the prospect of being an animal-whispering Disney Princess, unless you can figure out how to charge Pepé Le Pew rent for living underneath your home, it’s not worth it.

Common animals that claim squatters’ rights include:

  •   Rabbits
  •   Raccoons
  •   Possums
  •   Mice
  •   Rats
  •   Skunks
  •   The neighbor’s feral cat Mr. Whiskers

 Now, the vast majority of these animals are more of a nuisance than an actual threat to your family’s physical safety – unless you get bit by an animal with rabies.

Just ask our content manager, rabies shots are no fun.

However, one serious concern here in Southern California and Arizona is that these animals can attract dangerous predators, including but not limited to rattlesnakes.

Some estimates postulate that as many as 221 people are bitten by snakes in SoCal alone, equaling out to about 1.41 bites per 100,000 people.

The good news is that most rattlesnake bite deaths occur between 6 to 48 hours following the bite. And if the antivenom is administered within 2 hours of the bite, the odds of recovery are better than 99%.  

While the survival rate is amazing, the hospital bill can run upwards of $100,000.

In summary, void fill with polyurethane to keep animals out from underneath your home and protect your family.  

Polyurethane Void Fill Protects the Home from Rain and Moisture

Moisture is a bad actor when it comes to your foundation and if there is no void fill after your slab foundation lift, it can quickly turn into a horror movie.

Here’s the issue – water can run underneath your home and create a deeper, darker void. This, in turn, creates more room for animals and less support for your foundation.

Also, the more direct exposure your concrete slab has to moisture, the more likely spalling will occur – imagine rotten tooth decay but from underneath your gums. That’s the kind of issue we’d be dealing with.

Spalling was a major contributor to the recent Florida condo collapse that killed 98 people.

Spalling and water damage is no joke. In addition, the water can seep up and into your concrete soaking into your rebar. Rusted rebar can expand and break off chunks of your foundation with it.

Rust can expand to up to 7 times its original thickness and create 9000 pounds of pressure per square inch.  

In other words – your foundation won’t stand a chance. A compromised foundation can bite a huge chunk out of your property value, as much as 20% (as covered in our article 5 Reasons to Fix Your Foundation Now   

Don’t ruin your home’s equity and keep your family safe – fill the void.

Polyurethane Void Fill Provides Structural Support

Imagine your home is a trampoline. The legs of the trampoline signify the push piers and helical piers installed; the black rubber is the rest of your slab on grade foundation.

When weight is exerted onto the trampoline, the foundation sags where the weight is applied if there is no support underneath it.

This lack of support exerts a tremendous amount of force on the outside edges of your foundation and can cause the interior to concave and shift.

We here at Dalinghaus Construction Inc. take no shortcuts. We want your whole foundation to be supported.

Polyurethane is perfect to get the job done.

What is Polyurethane Foam?

Polyurethane foam is an injectable polyol and isocyanate resin sealantinsulationgrout which expands upon application providing void fill, structural support, and re-leveling properties. Polyurethane foam is waterproof, flame-retardant, noninvasive, and nonpolluting, weighing 3.5 to 5 pounds per cubic foot and reaching 90% compression strength after 15 minutes. Polyurethane can hold 7,200 pounds per square foot.

Choose Dalinghaus for Your Foundation Repair

 Not quite sold on the technological wonder that is Polyurethane? Check out our other articles on the subject:

We do foundation repair the right way. We believe in our process so much we have a lifetime warranty on all steel pier systems.

With over 100 years of combined experience and 4.9 stars out of 301 reviews – we are here to ensure that you never settle

If you live in SoCal or Arizona and would like a FREE foundation inspection, click the link below –


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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