Concrete is the most versatile building material accounting for the lion’s share of square footage in the skies and on the ground for construction projects.
However, despite advancements in construction and engineering, there is currently no indestructible concrete. If you have concrete slabs lining your patio, driveway, or pavement, you might come across sunken spots now and then.
In this article, you learn about mud jacking and all available alternatives. Traditionally, sunken slabs had to be lifted and replaced, but with mudjacking, you can have a level walkway by the end of the day.
Read on if mud jacking is the magic fix to your construction project.
What is Mudjacking?
Mudjacking, also known as slab jacking, injects a concrete slurry of sand, cement, water, and occasionally soil through two-inch holes drilled into concrete slabs to restore them to their original position. It was invented in Iowa but quickly gained popularity as an affordable alternative in concrete slab repair.
Mudjacking works by an infiltration mechanism where injected slurry gathers in holes and gaps within and below the concrete slab, consequently accumulating pressure that results in an upward displacement of the sunken slab.
Because of the nature of the slurry, the holes required for mud jacking provide an avenue for developing weaknesses in the slab. Furthermore, without professional help, you might exacerbate the situation while attempting a simple DIY fix.
Mudjacking might seem like a simple process upfront, but this is only sometimes the case. A series of steps need to be followed to the latter for excellent results. Several other steps might be needed depending on the extent of the damage incurred on the concrete slabs, while others may be excluded.
However, here are the key steps for every mud-jacking repair attempt:
1. Drill Holes
The concrete slurry is delivered to the slabs through pressurized holes that measure anything from one to 2.5 inches in diameter. Before you can go about transforming your perfectly intact concrete slab into a temporary sieve, there are several prerequisites to check off. The most important ones are highlighted below.
Assess the Extent of the Damage
Mudjacking offers a simple solution to sunken concrete slabs and is largely considered a reliable and semi-permanent repair. However, in case your concrete slabs are broken or have developed faults within their structure, then mud jacking will do little towards restoring their original state. Check for cracks and faults before deciding whether to proceed with mud jacking.
Determine the Cause of the Sunken Slabs
There are a number of reasons why your pavement may be sinking into the ground. Different causes require different approaches when it comes to repairing. The major concerns in slab sinking include:
Changes in Soil Moisture Content
Soil, like any other form of matter, has a fixed volume. In tandem with seasonal changes, soil tends to swell with an increase in moisture, as in winter or after a torrential downpour. When the water rescinds, the soil shrinks, resulting in a drop in your concrete slab level.
Trees are similar to icebergs because they have much more going on below ground level than what meets the eye. Despite the slim possibility that a mammoth ship will sink in your driveway, expansive root systems underneath concrete slabs might result in the uplifting or corresponding sinking of concrete slabs. Also, roots absorb water, altering soil structure and producing effects as described above.
Concrete is not waterproof, nor is the soil on which it sits. Poor drainage underneath your concrete slabs might result in an alteration in soil structure and moisture content resulting in the sinking of your perfectly aligned concrete slabs.
Proceed to Drill the Holes Appropriately
Once you know the nature and extent of the damage and potential causes, you are well on your way to beginning the mud-jacking repair process. Drilling holes to deliver the concrete slurry is the most crucial step during mud jacking. Concrete is durable, but it can also be brittle.
- Drill several holes two feet apart and two inches in diameter
- Take care to space the holes evenly
- Ensure the entire surface of the slab has evenly spaced holes
You might have heard of the phrase “measure twice, cut once.” For mud-jacking, drilling holes is the measuring aspect of the process. Appropriate drilling results in excellent lifting.
2. Lift with Slurry
The next step in the mud-jacking process is pumping the concrete slurry underneath the slabs. The slurry might vary in composition, but the strongest variants are usually comprised of the following:
- Portland cement
- Limestone aggregate
Lifting with slurry is dependent on hydraulic pressure generated by the setting slurry. The concrete slurry is injected through the previously drilled holes with caution taken on the amount delivered to each hole. Depending on how much lift is required, trained professionals pump varying slurry to ensure the slab remains level once the lift is complete.
Slurry pumped underneath the slab settles between the spaces left by displaced soil or expanding roots filling them out. Once the void is filled, additional slurry generates a significant hydraulic force for lifting the concrete slab.
3. Apply Finishing Touches
Once the concrete slab is lifted, there are still a few more steps to navigate. Those two-inch holes you drilled into the slab present a pathway by which weeds may sprout, taking away all that hard work you put in towards beautifying your driveway. To dot your Is and cross your Ts, you should fill the holes and caulk any visible cracks.
Caulking the cracks not only guarantees that your repair is not an eyesore but also prevents future erosion by agents such as wind and water that may widen the cracks developing lines of weaknesses. Once you are satisfied with the outcome of the mud-jacking process, you should refrain from loading the concrete slabs with significant weight for a few hours (the sweet spot is at 24 hours).
While you wait, it is a good idea to deal with any spilled slurry while wet to avoid having to chisel away any excess concrete. Unfortunately, those out-of-place bright spots left behind by the drilled holes will not fade as the day ends. You might need to cover up the driveway with
Mudjacking is a time-efficient process, and despite having significant damage incurred on the slabs, you should have a perfectly level driveway, pavement, walkway, or porch, by the end of the day. Similarly, when handled by professionals, the entire process is rarely labor-intensive.
When You Should Consider Mudjacking
Mudjacking is a convenient way to fix your concrete slab problems, but unfortunately, it is not an effective band-aid for all concrete problems. Depending on the extent of damage incurred on the concrete slabs, the cause of the sinking, your personal preferences and budget, and the permanency desired for the repair, mud jacking may or may not be the solution.
Mudjacking may come in handy when you are:
- Looking for a cost-effective alternative to completely replacing concrete slabs
- When the concrete to be repaired is heavy and has slab piers
- When you need to lift the slabs on your driveway, porch, walkway, patio, or pavement
- Pool repairs
Mudjacking is on the lower end of the scale when carrying out repairs on concrete slabs. With alternatives such as complete concrete replacement and polyurethane foam injections, mud-jacking offers competitive installation costs without sacrificing quality.
Mud jacking costs go towards buying materials and hiring injection equipment. You may pay for a small service if you hire professionals. It is always advisable to seek the services of a professional for good results.
On average, mud jacking costs usually range from $3 to $6 per cubic foot, depending on the extent of the damage. This translates to about $1300 for repairs on a mid-sized porch, patio, or driveway. However, in case of minimal repairs, costs may be as low as $300. For an accurate quotation, you should contact a trained professional.
Mudjacking is one of many ways to deal with dents in your pavements or sunken concrete slabs. If mud jacking does not sit right with you, you have several alternatives to sort that eyesore of a driveway. The ideal alternatives to mud-jacking are polyurethane foam injections and concrete replacement, which have certain prerequisites to attain before being considered.
Other alternatives include:
- Material slab jacking
Polyurethane Foam Injections
Polyurethane foam injection is a cut above mud jacking. Both mud jacking and polyurethane foam injection rely on hydraulic pressure to lift sunken concrete slabs. The biggest difference lies in the chemical composition of the slurry. As the name suggests, the latter uses polyurethane foam instead of concrete slurry.
How Does Polyurethane Foam Work?
Polyurethane foam has several advantages over mud-jacking. The foam material is injected in a liquid state, but in less than 15 minutes, the foam solidifies and fills the space underneath the concrete slabs. As it solidifies, polyurethane foam expands, providing sufficient force to lift the concrete slab and perfectly align with the rest of the slabs on the repaired surface.
The foam is injected through holes less than an inch in diameter, significantly narrower than in mud-jacking. Consequently, you have less to worry about when filling up the holes or attempting to hide those ugly and conspicuous spots left by the drilled holes.
Concrete Slab Replacement
Concrete slab replacement refers to the complete replacement of the concrete slabs. This is an expensive undertaking and is only considered in a worst-case scenario. As bad as it sounds, sometimes there are more cost-effective ways to manage dilapidated concrete slabs. So, what are the indicators for concrete replacement?
Wide Cracks and Gaping Holes
As mentioned earlier, concrete replacement is only feasible when the extent of damage to the concrete slabs is irreversible. When the concrete has visible cracks that span the length of the upper surface, then it is highly likely that the slab is broken into at least two pieces. In such a case, attempting to lift the slab will result in an unlevel surface which is not only an eyesore but also presents a trip hazard that might result in unprecedented trips to the emergency room or lawsuits.
Weakness in Underlying Soil
Occasionally, concrete may sink because of an alteration in the underlying soil structure. This is especially true for foundational concrete slabs. When the damage is extensive, extra weight from mud-jacking or polyurethane foam injections will only exacerbate the situation. Removing the affected concrete slabs allows you to compact the soil or apply stabilizing factors. This creates the ideal circumstance for concrete replacement.
How is Concrete Replacement Done?
Concrete replacement follows a series of highly regulated steps, especially when load-bearing equipment is involved. However, with the right tools and expertise, concrete replacement rarely takes more than a few hours. The steps involved include:
- Identifying and restricting the area to be repaired
- Sawing the concrete slabs along the edges of the outlined area
- Extraction of damaged concrete slabs
- Preparing the patch area and providing a load transfer
- Replacing the concrete slabs
- Sealing and insulating the concrete slab joints
Mudjacking vs Polyurethane
There is a lot of debate on whether polyurethane foam injection is better than mud-jacking. Most experts agree that polyurethane upgrades traditional mudjacking, but how do they compare?
Similarities Between Mudjacking and Polyurethane Foam Lifting
Both of these methods are highly effective when lifting sunken concrete slabs. In a nutshell, mud jacking and polyurethane foam lifting techniques rely on hydraulic pressure to fill the void left by the downward displacement of underlying soil or concrete slabs. Both the material, whether concrete slurry in mud-jacking or polyurethane foam in poly-jacking, is delivered through holes drilled into the concrete.
The lifting power is generated from the accumulation of the injected material in both cases.
Differences Between Mudjacking and Polyurethane Foam Lifting
There are several distinct differences between mud jacking and polyurethane foam lifting. The biggest difference is notably in the material injected beneath the concrete slabs. Polyurethane foam is a composite material made of polyol and isocyanic acid. This type of foam is much less durable than other types of foam but has more versatile uses, including poly jacking.
Mudjacking, on the other hand, depends on concrete slurry to generate the hydraulic force required to lift concrete. Furthermore, regarding the size of holes required to inject the material, polyurethane foam lifting utilizes holes significantly narrower than those used in mudjacking.
Polyurethane foam takes roughly fifteen minutes to cure, unlike mud jacking, which requires at least a day before the concrete slabs can comfortably support the additional weight. In terms of weight per cubic foot, mudjacking imposes far more weight than polyurethane foam, making it easier and more convenient for sensitive concrete.
The final significant difference lies in the cost of installation. Mudjacking requires minimal expertise and readily available construction material such as water and cement, making it relatively cheaper than polyurethane foam. However, polyurethane foam is the more cost-effective option, with a life expectancy of five-plus years as opposed to two years for mud jacking.
Which is Better?
Polyurethane foam lifting is the better option due to its extended life expectancy, minimal maintenance costs, and simplified installation. However, you shouldn’t write off mudjacking just yet. If you are on a budget, or simply looking for a temporary solution to your concrete problem, then you may still consider mudjacking as an option.
Polyurethane foam, however, offers minimal repercussions should the repair not go as planned. A good example is if the ground underneath the concrete is unstable. You may inadvertently cause the ground to sink further when using mud jacking. Because of the light nature of polyurethane foam, it is less likely to exacerbate sinking concrete slabs.
Frequently Asked Questions
Let’s take a look at some common questions regarding mudjacking:
Is Mudjacking a Permanent Fix?
How Much Weight Can Mudjacking Lift?
Mudjacking Is a minimally invasive procedure used to raise and level sunken concrete and can lift weights ranging from 600 pounds to 1400 pounds per square foot of concrete. However, depending on the extent of damage and quality of the concrete, these values might deviate on either side.
Is it Cheaper to Mudjack a Concrete Slab or Replace it?
If the concrete slab is not damaged, it is much cheaper to mud jack it than to complete a concrete replacement. Mudjacking requires less labor, material, and time making it the more cost-effective option. However, concrete slab replacement might be the only viable option in case of adverse concrete damage.
Mudjacking, despite being considered a traditional version of slab jacking, remains an effective way to fix unlevel concrete slabs through hydraulic lifting instantly. It is minimally intrusive and less likely to produce mismatched slabs, as in concrete slab replacement.
However, if you have a few extra bucks to spare, then you are better off going for polyurethane foam lifting as it is more durable and cost-efficient in the long run.