Does Polyurethane Prevent Foundation Settlement Without Piers?

It’s no secret foundation repair isn’t cheap. Looking for more affordable methods can be difficult. The thought of using a cost-effective method for foundation repair is appealing. Polyurethane without piers has had occasions of being as effective as piers on its own. 

But does polyurethane as effective in foundation settlement without piers? The short answer: it depends. Don’t expect it to be the first option.

Dalinhaus Construction has done over 2,000 foundation repair projects in Southern California, Arizona, and Nevada, with a good chunk involving polyurethane in some form. A small portion of those projects has involved lifting a home using only polyurethane. This is rare. And we want you to understand why using polyurethane for a home lift is rare. 

 

What is polyurethane?

Polyurethane is a foam material composed of polyol and diisocyanate that combine to make a foam as hard as concrete when injected underground. 

It’s a better alternative to mud jacking, which uses concrete to reinforce a settled structure. The issue with concrete is that it contracts as it dries. Polyurethane expands and stays that way when it solidifies. 

Plus, concrete can sometimes acts as an anchor, meaning it will sink into the soil.

Poly is meant to last hundreds of years. It’s effective and permanent, but the soils and everything around the poly are susceptible to movement and change. 

 

What is polyurethane used for?

Polyurethane is mainly for void fill and slab foundation releveling. Sometimes it’s used to lift columns, houses, roadways, patios, etc.

When polyurethane is used for lifting, it won’t be used for a major lift.

If polyurethane is used on its own, it depends on: 

  • The weight of the structure. 
  • The footing. 
    • How deep is it?
  • How many stories, 
  • If the building is commercial, 
    • If the structure is a tilt-up. 
  • If the building is a normal home.
  • If there is a single garage.
  • If there is a shed
  • What the soils are like.
    • Are they expansive or sandy soils?
    • Are they wet or dry soils?
  • Where the structure is located.
    • Is it near the beach, desert, forest, etc.
  • Is the structure on a flat lot or a sloped lot?
  • Is there a hillside?
    • How close is a structure to the hillside? 
  • Where is the bedrock?
  • Has other work been done on the structure before?


As you can see, there are many things you need to look at when using polyurethane by itself. The reason for this is to make sure it can be as effective as possible. 

If a factor isn’t accommodated, the polyurethane won’t work effectively in the job you want it to do.

Polyurethane can SOMETIMES prevent further settlement without piers, but don’t count on it to be the first option. It’s tricky since the conditions have to be next to perfect.

We don’t often see projects where polyurethane is doing the heavy lifting. We see this maybe 10-15% of the time. In most cases, you would need push or helical piers installed with the poly injection.

Again, it depends on the circumstances. 

 

When polyurethane is usually applied

Polyurethane will be injected into the ground to accommodate slab-on-grade foundation homes. The foam will be injected typically by the end of a project. 

After a lift, there are voids in the soil that are unaddressed. Void filling with polyurethane fills in the voids to stabilize the slab and the concrete footing. 

Polyurethane is also used to densify the soil. While the substance comes out as foam, it becomes as hard as concrete in 15 minutes.

Polyurethane could be used in place of piers but is better used in conjunction with piers as an assistant. 

Polyurethane is used for concrete lifting

If you’re just doing a slab – which can be three to six inches thick – for patios, roads, or driveways, the poly can work more effectively by being injected into the soil, void filling, and then lifting. Lifting these are much lighter than trying to lift a home or a building. 

 

Is Polyurethane Dangerous?

No. 

You don’t need to worry about any potential dangers. Polyurethane is environmentally safe when it cures and doesn’t contaminate the soil under your home. 

You don’t want to mess with the individual components to make the polyurethane foam, since they can cause eye damage and irritation. They can also be dangerous for reproduction.

The combined substance is safe. Polyurethanes are so safe they’re used for pacemakers put in people’s bodies.

If polyurethane was to dry on your skin, it would be a little uncomfortable due to the chemical reaction heating up during the foaming process. And ripping off the dried parts might make it so you lose some chest hairs. 

For more information on the “dangers” of polyurethane, there’s no danger in reading our article Is Polyurethane Dangerous? (Why You Don’t Need to Worry).

 

Polyurethane can be a cheaper alternative to using piers

Again, don’t expect this as your first option. 

If it’s a possibility, you eliminate the cost of installing piers to your home and reduce the labor needed. However, it isn’t warrantied or as permanent as installing push piers or helical piers. 

If a piering job costs around $35,000, a polyurethane job on its own can cost around $10,000.

The cost is appealing, but the longevity of the repair is different and not entirely guaranteed. 

Overall, piers and polyurethane (again, for a slab-on-grade home) are better solutions.

Plus, the amount the polyurethane can lift your home is unknown due to the many factors we discussed earlier.

 

You know more about if polyurethane can be used without piers. Look into the other alternatives.

You’ve learned what polyurethane is, what polyurethane is used for, if it can substitute piers, if polyurethane is dangerous, and how it could be cost-saving. Because polyurethane used to lift a home likely won’t be the first option, look at other methods foundation repair is done. 

Read and see our article Does Foundation Repair Fix My Home Permanently?

For pricing, check out How Much Does Foundation Repair Cost? (by Mark Cook)

For additional questions, call Dalinghaus Construction at (877)360-9277.

WRITTEN BY

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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