What is Polyjacking? Foam Foundation Repair

Polyjacking is an increasingly common technique used when it comes to raising up slabs of concrete. If your foundation is sinking, it is possible to address the problem in a relatively non-invasive way by injecting high-pressure foam underneath the slab to lift it up. 

This guide will cover everything you need to know about polyjacking, from the way it works to the pros and cons, as well as the costs you can expect to pay. Although it’s not an ideal situation that your foundation is sinking, all is not lost.

How Does Polyjacking Repair a Foundation?

One of the remarkable things about polyjacking is how relatively simple the entire process is. Even if you’re dealing with space-age technology and using it to lift an entire house, it is not a complex process. 

The first step in polyjacking is conducting a survey of the property and the amount of foam that is needed. Once you know much you need to lift, you can calculate how many holes you need to drill and where. These holes are roughly ½ inch in diameter (which is around the size of a penny). These holes are drilled in key locations where the slab has sunk. 

Once the holes are all drilled, nozzles are added. These nozzles are clamped into place so that they won’t move even as the high-pressure foam is being pumped through them. 

The foam is then ‘injected’ through the nozzles and under the slab. The slab is monitored, and the foam is pumped through until the slab is at the correct elevation. At this point, the pumping stops, the nozzles are unclamped and removed, and everything returns to normal. The drill holes will be filled in with caulking and should be relatively invisible to the naked eye. 

The foam cures instantly, which means that you don’t have to wait before re-entering your home. All in all, the process can take less than half a day and leaves very little evidence that it has taken place at all (apart from the fact that the concrete foundation slab is no longer sunken).

When Do I Need Foundation Repair?

Polyjacking as a process will only work if you are able to work with an undamaged foundation. If your slab has sunk too much, you won’t be able to use polyjacking, and you’ll need to go with a (much more expensive) slab replacement instead. As such, you should always be vigilant for signs that your foundation is sinking. Below are the four most common signs to look out for:

  • Cracks in the foundation. Cracks in the foundation are caused by the tension of a sinking foundation—the forces act in unusual directions upon different parts of your home. In particular, you should be looking for cracks that change in shape or size over time and cracks that are wider at the top than at the bottom.
  • Damage around doors and windows. If you notice that there are cracks, crumbling pieces of drywall, or any other damage around doors and windows, it can be the case that the foundation is sinking. Doors and windows form the structural weak points and are often the first places to show damage.
  • Sticking doors and windows. Like with the damage around the frames of windows and doors, signs that they are getting harder to open can also suggest that there has been a movement in the skeleton of the house. You should also look for gaps where there were none before.
  • Uneven floors. Obviously, if part of your home is sinking, it will impact the level of the floors. If you notice that water is pooling in a strange way on the floors or that the ground is no longer level, it’s time to take action.

What are the Benefits of Polyjacking?

So, let’s say that you do notice that your foundation is sinking (and it’s confirmed by a professional). You have a range of options when it comes to precisely what course of action to take. Our article on the different types of concrete lifting will go over these options.

However, polyjacking is likely to be your first option. Firms that are able to offer polyjacking usually have their own proprietary foam. Therefore, the actual advantages vary slightly from company to company, although polyjacking, in general, has a number of advantages over other types of slabjacking. These include:

  • Time. As mentioned above, a seriously strong argument in favor of using polyjacking is that it takes no time to cure. As soon as the foundation is raised into place, the job is complete.
  • Cleanliness. Unlike with other types of slabjacking, polyjacking requires no heavy machinery to pump it in. This means that it is an extremely clean and low-intensity process.
  • Small holes. Compared with something like mudjacking, polyjacking only requires small holes to be drilled in the slab. This means that there is an aesthetic benefit, as well as meaning that there is less chance of water seeping in.
  • Weight. The polyurethane foam may be strong, but it is extremely lightweight. This means that it is unlikely to cause further sinking of the slab. Polyurethane foam is roughly 50 times lighter than the slurry used in mudjacking.
  • Eco-friendly. In most cases, the polyurethane foam used in mudjacking is made up of recycled and renewable material. This means that its carbon footprint is lower than with other types of slabjacking material.

These are all fairly significant advantages – and they are only increasing as the technology involved in developing polyurethane foam improves.

What are the Limitations?

Despite the fairly solid list of advantages of polyjacking outlined above, there are a number of limitations that mean that polyjacking isn’t always the automatic selection for contractors and homeowners. Below are some of the factors you’ll need to consider before you sign up for polyjacking to repair your home’s foundation.

  • Incomplete cavity filling. One of the problems with using foam rather than a slurry is that you may leave gaps beneath the structure of the home where the foam has not reached. This means that there will be inherent weak points in the foundation, which may lead to crumbling and other problems in the future.
  • Safety hazards. Although most polyfoams are extremely safe, some contain additives that may be harmful to the environment. As such, you should be extremely diligent about what polyurethane foam your contractors are using.
  • Strength. Polyurethane foam often offers a great deal of strength, although not the highest amount possible. For example, polyurethane foam usually has a compressive strength of between 80 and 100 PSI. By comparison, some forms of mudjacking can achieve compressive strengths of above 2,000 PSI by the addition of cement or a cement and sand mixture.
  • Cost. Polyjacking has a great deal of variance when it comes to the overall cost. In most cases, however, it will be more expensive than mudjacking, primarily because of the differences in materials used. The section below will discuss costs in more detail.

Of course, no home improvement project is going to be exclusively better using one material or technique. Therefore, you’ll need to weigh up the benefits yourself. However, there is a reason why polyjacking is becoming more and more common, as the advantages increasingly outweigh the limitations.

How Much Does Polyjacking Cost?

The cost of polyjacking can vary a great deal depending on which firm you use (remember, they’re using their own foam for the project), the nature of the project, and the cost of living in your area. As such, you should always aim to get at least three quotes for any work. 

Generally, however, you can expect to pay somewhere between $2,400 and $3,600 for an average residential polyjacking project. If you live in a smaller home, you can use the rule of thumb that polyjacking a foundation slab will cost somewhere between $5 and $25 per square foot. 

If you live in a larger home or are getting quotes for a commercial property (the cut-off here is usually about 20,000 square feet), there is a slight economy of scale, and you’ll pay somewhere between $3 and $20 per square foot. 

To put it into perspective, mudjacking your home’s foundation will cost between $3 and $6 per square foot, meaning it will almost always end up being a cheaper option. 

Ultimately, polyjacking may seem like the perfect solution to your foundation-sinking problem. It’s minimally invasive; it is extremely quick and extremely effective. Although you may pay more for the process than you would with something like mudjacking, when you consider how unobtrusive the process is, as well as how long it will last, it becomes a more attractive option. 

This is particularly true when compared with the cost of inaction. Failure to act will mean that you are faced with an ever-mounting bill and a collapsing house. So if polyjacking is available, you should consider yourself lucky, as it means you’ll be spending thousands, not tens or hundreds of thousands.