Do you have a concrete slab that is settling, cracking, and sinking? If so, you’re not alone – this is a common problem for home and business owners. Fortunately, there are many solutions to help prevent expensive repairs or the need to replace the slab entirely.
We’ll explore four methods of addressing settling concrete: foam jacking, mudjacking, epoxy covering, and total replacement. Read on to find out more!
How to Approach A Concrete Lifting Project
There are basically four different approaches to addressing these issues. At the time of this article, Foundation 1 can provide three of the four methods. This blog post is designed to highlight the positives and negatives about each one. The pricing is very different on these projects. Listed below are the four methods and an APPROXIMATE average that each one would cost (all are based on square footage, so the numbers below are designed to approximate a typical project.)
- Method 1: Mudjacking $800 to $1,500
- Method 2: Polyjacking $2,000 to $4,000
- Method 3: Epoxy Cover $5,000 to $8,000
- Method 4: Tear Out & Replace $6,000 to $12,000
As you might imagine, the most common approach is the cheapest, mudjacking. Importantly, the first two methods (Mudjacking and Polyjacking) are NOT considered cosmetic repairs. In other words, they will not make the concrete look “prettier” than it currently is. The last two repairs ARE cosmetic in nature.
Often these are initiated by concrete settlement and/or cracking. Settlement happens when the supporting soils underneath the concrete are not strong enough to keep the concrete in the place it was prior. Concrete is heavy, and it can compress the soil beneath it. This can lead to concrete sinking.
Similarly, water can wash away the soils around (and under) the concrete slab which can lead to settling. And dirt absorbs water forcing it to expand and contract through wet and dry weather cycles, and can also cause concrete to settle. Any time concrete is settling or sinking, it is at risk of cracking.
Voids Under the Concrete
Another factor which comes about is voids underneath the concrete. While the concrete may basically stay in place, the supporting dirt underneath either compacts or gets washed away leaving spaces between the dirt and the concrete.
As surprising as it may sound, we see situations where there is an 18-inch void in garages between the concrete and the dirt. (Yes, imagine parking a car on this!) Needless to say, if concrete has a void underneath it, it is not property supported and is at severe risk of settling and cracking.
It also makes sense to speak about concrete and cracking. If you speak to super experienced concrete guys, they will tell you there are two absolutely certain things about concrete. The first is that it will harden. And the second is that it will crack. Over the course of time, all concrete will eventually crack.
For this discussion, then, it is helpful to think in terms of this concept: Concrete has a certain expected life cycle. It is easiest to think of this in terms of a driveway or a sidewalk. Let’s say the number is 30 years. When it is poured it has the most attractive appearance that it ever will. Over the course of time, cracks develop. Towards the end of its life, the cracks overtake the slab. Eventually the person decides to remove the old concrete and replace it. This is the TYPICAL life of a concrete slab.
The different approaches to addressing sinking, cracking concrete all look at these factors. Let’s look at them specifically.
The most common, and as highlighted above, the least expensive repair is mudjacking. The repair approach has been around for many decades (about as long as concrete itself) and is considered to be a “standard” or straightforward approach.
It works by identifying the areas where concrete is settling or where there may be a void under the concrete. (There are several ways to do this.) When the area is identified for repairs, holes are drilled about every 5 to 8 feet, or in specific spots to accomplish specific “lift” goals.
When these holes are drilled, a “mud” mixture (consisting of fly ash and Portland cement) is mixed and hydraulically pumped – under pressure – into the holes. This fills the voids under the concrete slab and can lift the concrete back to a more level position.
In some instances, concrete will have settled and impinged the concrete, limiting its ability to be lifted. In some circumstances, this concrete can be cut to free up the concrete slab to lift with the mudjacking. As you might imagine, this can help level the concrete, but does modify / impact the visual appearance of the concrete.
At the end of the process, the holes are refilled with concrete. It is highly probable that the concrete colors will vary, so it should be expected that these holes will be visible in the concrete after the repair. Additionally, at the conclusion of a mudjacking project, cracks can be temporarily filled and joints sealed, but these solutions are not permanent, as they do not address the structural challenges (which likely caused the cracking initially) and will likely open again over time.
The Positives of Mudjacking
- You can start with the price; it is the least expensive method.
- It is the most proven method with decades of effective use.
- It does an excellent job of filling voids.
- It does an excellent job of lifting concrete.
- It provides a solid material under the concrete slab which can support the weight of the concrete over time.
- Mudjacking can be done again at a later point in time, should it be necessary.
- Extends the life of concrete slabs by filling voids and supporting the concrete.
- Minor cosmetic repair can be completed on cracks / joints, but this tends to be somewhat temporary.
The Negatives of Mudjacking
- As mentioned above, mudjacking is NOT a cosmetic repair; it does not make ugly concrete pretty.
- As mentioned above, there will be color variances between the concrete and where the holes were drilled.
- As mentioned above, concrete does crack and lifting sunken concrete can lead to additional cracking.
- Mudjacking, like concrete, must be done in dry weather conditions above freezing.
- Lifting concrete which has sunk, can reveal or even cause additional cracks in the concrete.
- There are factors which can limit the “lift” of Mudjacking, including poor drainage, impingement, concrete is too cracked, concrete is too thin, supporting soils are too wet, etc.
- If poor drainage is the underlying problem, if the drainage is not fixed, Mudjacking will be a somewhat temporary solution. (This is true, however, of all of the methods. Water harms concrete and the soils underneath it, regardless of repair method).
Polyjacking is very similar to mudjacking, and many of the plusses and minuses are the same. The primary difference is that instead of injecting a “mud” mix like mudjacking, it injects an expandable polyurethane foam.
The Positives of Polyjacking
- The holes are about half the size of mudjacking.
- The foam material itself will not wash away with poor drainage. (With mudjacking, water can wash away the mudjacking materials – and the dirt. However, water will wash away the dirt underneath polyjacking, so if there is a drainage problem, it is best to address that at first!)
- The foam materials are lightweight and do not add weight to an already sinking (heavy) concrete.
- Also extends the life of concrete slabs by filling voids and providing support under heavy concrete.
The Negatives of Polyjacking
- Nearly all of the negatives of mudjacking also apply.
- It is 2X – 3X as expensive as mudjacking.
- It is relatively new; the long-term results are not fully known.
- It is injecting a chemical under your concrete; mudjacking materials are more natural.
- Some question whether the lightweight foam can effectively support the heavy weight of concrete over the course of time.
Because of the similarity of two approaches, here are our suggestions on “when to choose”.
When to Pick Mudjacking Over Polyjacking
- When price matters
- When you feel like you have addressed underlying drainage problems
- When you would rather do the less expensive repair, but more regularly
- When you have a very heavy slab and plan to park cars on it
When to Pick Polyjacking Over Mudjacking
- When the size of the holes matters
- When you are not effectively dealing with drainage issues (but even this can be a challenge with Polyjacking)
- If you need the work done in the winter
- If you are doing an epoxy covering (see next repair method)
By the way, if you are not 100% sure about which method to use (between Mudjacking and Polyjacking), don’t be surprised. It is not a perfectly clear answer. However, there does tend to be a rush in the industry towards Polyjacking over Mudjacking. We are not sure that this is due to any inherent advantage, or whether it is simply a way to charge more for a concrete leveling project. (At present, Foundation 1 offers mudjacking and NOT polyjacking. This could change in the future, as we wait to see how things evolve. For now, however, we are sticking with the “tried and true.”)
Again, before moving to methods 3 and 4, it is important to reinforce that methods 1 and 2 will not make ugly concrete pretty. The last two methods will improve the cosmetic appearance of concrete.
This is the first of the “cosmetic” repairs, and is quite a bit more expensive than polyjacking or mudjacking. It is, however, very attractive and can be an excellent option.Let’s use the example of a garage. You have a decent garage, but there is some concrete settling and cracking. You would like to have a very nice garage. With this repair, the first thing is to support the concrete underneath the slab. If you do a cosmetic repair, and have not addressed the fact that the concrete is settling, the repair will not be “cosmetic” for long. Basically, that means that the first step is to do either mudjacking or polyjacking to fill the voids. Given the foam will not erode away with any water, this may be a case where polyjacking is an advantage over mudjacking (see prior note).After filling voids and leveling the concrete, an epoxy covering will be applied. The first step is to do a layer which will fill in any cracks or imperfections. It is important to note that this is NOT a structural covering (ie: as strong as concrete), but rather is a cosmetic filling. It will, however, do an excellent job of making the concrete look more consistent.After the “smoothing” layer, then decorative layers of epoxy can be applied. Epoxies are available in every color and sheen you can imagine. These are extremely attractive.In the context of a comparison to other methods here are the pluses and minuses.
The Advantages of Epoxy Covering
- Very attractive finishes
- Makes “less than perfect” concrete look very nice
This Disadvantages of Epoxy Covering
- You still need to level concrete, fill voids, and support it, so it will be in addition to Mudjacking or Polyjacking if you have an underlying settlement issue
- Higher cost solution.
- Cracks will still develop, especially if there are underlying “settlement” issues associated with the base concrete. Epoxy is for appearance, not for added concrete strength.
The Best Way to Level Your Concrete
All four of these are viable approaches to dealing with concrete issues. As you can see, none are perfect. This highlights the importance of working with a company who can give you an objective assessment of the situation and a strong recommendation based on experience.
It is not common for companies to offer more than one or two of the types of repairs, and Foundation 1 is able to (at the time of the writing of this article) provide three of the four. Contact us and we will discuss with you our thoughts and how they apply to your specific situation and goals for your property.