What is Polyjacking? The Poly Foam Injection Used in Foundation Repair

You may have heard the term polyjacking somewhere and just pretend like you know what it means with nods and yeahs. But really you’re like, “Does this have something to do with stealing parrots or something? Cuz I would rather talk about foundation repair for my home.”

Anchor Foundation Repair

At Anchor Foundation Repair, we have been inspecting and repairing foundations since 1985 right here in the Bryan-College Station community, as well as other towns like Brenham and Navasota. We often run across homes that can use polyjacking and see the value in this service’s role in certain foundation repair projects.

We do not do polyjacking ourselves, but we have worked with polyurethane injection companies in the past. We find foam’s ability to raise the center of a home impressive. It’s a great fit for certain scenarios and I’ve recommended it hundreds of times . . . even if that means we don’t get to do work for a homeowner.

Let’s take a look at what polyjacking really is, and what kinds of situations it works well for in foundation repair. We will explore any pitfalls to using the method and alternatives too.

What Actually is Polyjacking?

Polyjacking has many names, like poly-leveling, polyfoam injection, poly-lifting, foam jacking, slab jacking, and the list seems to go on . . . 

polyurethane foam product

At any rate, polyjacking uses high-density polyurethane foam and injects it under your home from above. The foam raises the home back to its original elevation.

This polyfoam is a powerful product that works by compressing the soil underneath a home and then allows for the lifting of the structure. The foam expands as it is injected (picture what happens with shaving cream when it comes out of a can). But unlike shaving foam, it dries to a rigid material like the hard styrofoam used in packing and protecting electronics for shipping. 

Similar to foam insulation but specifically designed for raising concrete, this polyurethane foam is actually very strong when dry. In fact, it is often used in highway repair to lift sections of road and holds up to semi-trucks and thousands of cars driving over it daily.

In home applications, polyjacking can be used with simple exterior concrete surfaces like sidewalks and driveways, but can also be used in home foundation repairs (which is what we are talking about today). It is especially good for lifting underneath the interior of a home.

If you are more interested in polyjacking for simple concrete flatwork outside the home, check out this article about methods of repairing sunken concrete.

How is Polyjacking Done In Foundation Repair?

A series of small holes (around ½ inch or maybe the size of a dime) are drilled completely through your slab-on-grade foundation. The holes are placed in key locations where the slab needs to be lifted up from below. Then, a row of nozzles is inserted into the holes and clamped into place before starting the injection process. 

poly foam injection holes

The process is like jacking up a car to change a flat tire. The car is lifted from below and raised to where it needs to be. But it’s not exactly like jacking a car because the foam is injected in from above and expands up to create the lifting below.

The pressurized foam is injected under the home through the nozzles and is monitored until the slab reaches the proper elevation. Then they stop and fill the holes back in with a bit of concrete to patch it up. 

Your flooring (or concrete surface) will have evidence of holes being drilled into it. But they are small so some people can find ways to cover them, patch them up, or don’t mind the imperfections.

How Long Does Polyjacking Take? What About Cost?

The average interior home polyjacking project for a foundation probably takes just 1-2 days to complete. This is in stark contrast to doing interior pier work with drilled bell-bottom piers, which could take 8 to 10 weeks.

The cost of polyjacking under the interior of the home is harder to estimate since we don’t provide this service, BUT our guess is that it’s about a third less or even half the cost of drilled piers. The cost savings are primarily due to the significant installation time difference between the two methods.

Are There Any Problems with Polyjacking for Foundation Repair?

Well sure, any method comes with potential problems or shortcomings . . . that’s why it’s so hard to pick one! Polyjacking is really great but has its fair share of things to be concerned about and consider including floor damage, plumbing risks, and longevity uncertainties.

holes for polyjacking
This is about how far holes would be spread apart in polyjacking.

Floor Damage

We touched on this earlier, but to repeat: your flooring will get holes in it. They are on the small side and easy to hide or patch. BUT you will either have to live with the results of patching or if you don’t like how it looks afterward then you might have to/want to replace your flooring. 

If you were going to replace flooring anyway, or you have carpet then it’s not as big of an issue. Ultimately, it depends on where the lifting needs to take place in your home and if the flooring in that area can easily be camouflaged. Or is the area exposed and obvious in a way that is not to your liking?

Plumbing Risks

As with any foundation repair project, your under-slab plumbing is at risk and care needs to be taken to work with and around it. Plumbing lines need to be checked both before and after the polyjacking takes place.

Before the job, under-slab plumbing should be checked for leaks to make sure there are no existing cracks or separations in the lines that the polyjacking material could intrude into. Filling your plumbing lines with foam is a sure way to clog them up.

If there are leaks under your house already, they might have been the thing causing the foundation settlement in the first place. So you would want to get everything sealed up properly no matter what.

plumbing under your slab on grade foundation

There’s also a chance that when the holes are drilled for the polyjacking material, a supply line could be nicked or drilled through so they do have to be careful. You don’t really want your repair to cause other things to need to be repaired, but it can happen. 

If it does happen, then you would need to either break through the slab from above for plumbing repairs OR use under-slab tunneling so that plumbers can repair the problem less intrusively from below.

After the polyjacking is done, the act of raising the home can also sometimes cause drain lines to detach or break as well. So the plumbing needs to be checked AGAIN to make sure that didn’t happen or if it did, then it needs to be fixed. 

In other words, you would want to make extra sure that whoever is doing your polyjacking for you is planning to check plumbing both before and after the lifting process. This is to protect your pipes and make sure there are no leaks. 

If they don’t do it as part of the polyjacking service, we highly recommend calling in a plumber to test your lines and make sure there are no leaks before and after the work.

Repair Longevity

expansive clay soils

Polyjacking under a home will provide years of stability. But we can’t say that it will last as long as more traditional foundation repair methods, like drilled piers. While the polyjacking material itself will not degrade and will last *probably forever* under your home, it’s still resting on top of unstable, expansive clay soil that may lead to further settlement.

Polyjacking is a shallow, surface fix that will certainly elevate your foundation to the desired level. But it doesn’t penetrate into the ground past the unstable layers of soil the way that piers will. Polyfoam also does not have any structural means to resist uplift the way that piers do. 

Polyurethane foam is a space filler and a lifter, but not an anchor or a true stabilizer because it just isn’t made that way. It’s essentially floating on top of the soil rather than going through it and gripping the soil below through friction and resistance.

Less repair longevity means that you might have to have your home polyjacked again in the future if further interior foundation settlement occurs. But the good news is that the same holes can likely be used. Since the cost is lower than traditional foundation repair methods too, you might not mind paying more later for a redo.

What is Polyjacking Best for in Foundation Repair?

Polyjacking is a fantastic product for some homeowners that we meet with for foundation inspections. We have recommended this service hundreds of times because we believe in it so much and it is a great fit for homeowners in *certain situations*.

Best In Combination with Traditional Foundation Repair

If a home needs both interior and exterior foundation support, meaning support under the middle as well as around the perimeter, then polyjacking is a great interior application to use in conjunction with drilled piers around the outside.

The biggest benefits to polyfoam injection for interior settlement vs. piers are:

interior foundation settlement
  1. Less interior mess
  2. Shorter installation time
  3. Less cost

When you need interior foundation work (10% of homes do), polyjacking for the interior will be significantly less intrusive to your home. You won’t have to pack up your things and move out of the home temporarily during the process and your floor won’t be heavily impacted. It will only take a few days rather than weeks. 

We’ve installed thousands of interior piers in our day, but have yet to figure out how to do it without making *a bit of a mess* inside a home (which is why you need to move out when it’s being done).

These are some big *pros* for polyurethane foam injection when you combine it with drilled piers around the perimeter of your home. Drilled piers offer increased stability and longevity around the outside, while the poly does a great job filling and lifting under the inside and avoids life disruptions.

Interior pier work also has a higher cost than perimeter piers, so saving money on the interior part of the foundation repair is best for some people as well. Though you may have to go through separate contractors for each service.

Best for Repairing Foundations of Older, Lighter Homes

home foundation repair

Because of some newer building codes that make homes heavier, we do not typically recommend using polyjacking for homes built after 2002. Especially if the newer home is two stories tall or very heavy for other reasons, then polyfoam injection might not be the best choice because it’s not quite strong enough to provide the needed lift.

So if your home was born before 2002 and is lighter, then it could be a good candidate for polyjacking as a singular foundation repair method, or in combination with drilled piers.

Can You Recommend a Polyjacking Contractor?

We will be the first to tell you if we think you and your home are a good candidate for polyjacking. It’s typically during our In-Home Assessment appointment (after we have taken a good look at your home situation and heard your concerns) when we would normally make a recommendation of this kind. 

But I can certainly tell you what company I always suggest right now and that’s Uretek. They are out of Houston and are the world’s leader in the polyfoam injection industry. They are the true experts in this field at the moment, but someday we hope to offer polyjacking as well so that you don’t have to go elsewhere for this service.

Are There Alternatives to Polyjacking?

drilled bell-bottom pier foundation repair

Sure, there are alternatives to using polyjacking under the interior of your home. First, you could do nothing about the signs of foundation settlement you are seeing in your home, but that’s not particularly proactive. Second, you could use drilled piers or pressed pilings for a traditional foundation repair on the perimeter as well as the interior.

At Anchor Foundation Repair, we have been serving local Brazos Valley communities in Central Texas for 35+ years and we intend to stick around. We always put ourselves in your shoes when making recommendations for foundation repairs, and sometimes that leads us to suggest using a different foundation repair contractor or a different method of foundation repair that we don’t happen to provide. 

We’re okay with that because we want what is the best choice for you and your home situation.

Check out this article that reviews different methods of slab-on-grade foundation repair and see if there’s another method you think might work better for you.