Mudjacking (Grout Injection) vs Polyurethane Foam

BASED ON CONCRETE LIFTING KNOWLEDGE AND EXPERIENCE Since 1991

MUDJACKING SINCE 1991 / POLYJACKING SINCE 2012.

MUDJACKING CHARACTERISTICS

1″ inch diameter holes.
Non-expanding material.
Material: Sand, Fine Clay and Cement Grout Mix.
Double piston hydraulic pump to inject grout mix.
Enviromentally friendly.
Material starts setting within hours.
Proper grout material doesn’t erode away and will last the life of your concrete pad.
The fine clay content allows the grout material to slide underneath the concrete and gives the grout material its structure. The cement is for added strength and the strength can be changed by how much cement is added to the grout mix.
Long term solution if ground settlement is finished and water is directed away from the concrete pad. The installer raises the concrete to its proper height and fills all the voids.

MUDJACKING PROS

Long term solution.
Non-expanding grout material.
Grout material can be adjusted in strength depending on how much cement material is added to grout mix.
More precise lift and more control when lifting concrete with a non-expanding grout material.
Better job done in the void filling process. Higher sucess rate of all voids being filled.
While installing the grout material the longer set up times allows the concrete to float up to height causing less cracking and a higher success rate of raising the sunken concrete to its original height and filling all the voids.
Longer set up times allows the concrete to tilt and match trip spots better, take dips out of the concrete better as it allows the concrete to slide on the grout layer.

MUDJACKING CONS

Materials are harder to fine and not as readily available.
More equipment and labor is needed to raise concrete with.
Sucess rate raising sunken concrete and understanding how to fill voids properly totally depends on the experience and knowledge of the installer.
Every job is different when raising concrete, this is why it takes many of years and decades to fully understand how to raise sunken concrete and how to properly do the void filling process to ensure all voids are filled. Concrete Lifting is not just about raising the sunken concrete it is also about filling all the voids too.

POLYURETHANE FOAM CHARACTERISTICS

Polyurethane foam material: Expanding 2 part chemical reaction.
5/8″ inch diameter holes.
Polyurethane foam materials are engineered and have different denisty of foams for different applications.
A Reactor is used to heat and pump the 2 part chemical to the injection gun. The injecton gun mixes the 2 part chemical and injects the liquid material through 5/8″ inch drilled holes. The 2 part liquid reacts underneath the concrete making the expanding polyurethane foam material which fills the void in the area its being injected and then lifting the concrete.

POLYURETHANE FOAM PROS

Less labor and equipment to raise concrete with.
Lightweight material
Fast set up time fully set with in 15 mins which can be advantage in certian applications
Long term solution if ground settlement is done and water is directed away from the concrete and this also depends too on installer knowledge and experience.
Can be good solution for limit access interior sunken concrete projects.
Can be a good solution in certian applicatons for heavy sunken commercial and industrial concrete slabs.

POLYURETHANE FOAM CONS

Expanding material
Harder to control the concrete while raising the slab because of the expanding polyurethane foam material.
Void filling process is guess work because you can’t see underneath the concrete to know how much expanding polyurethane foam material to inject.
Installers tend to skip putting enough 5/8″ inch holes in the concrete to raise and fill the voids.
Risks of over lifting the concrete slab are high while raising the concrete to height and trying to fill the voids underneath the concrete.
Installers need to express patients when installing the expanding polyurethane foam material while raising the concrete to height and filling the voids best as possible.
Set up times being almost instant doesn’t allow the concrete to be floated but forced up to height which can cause more cracking. and harder to obtain original height.
Voids not being filled properly and concrete pads left hollow.
Taking out dips in concrete can be impossible because of the fast set up times it doesn’t allow the concrete to slide and makes foam layers underneath the dip not allowing the dip in the concrete to be pushed out.
Fast set up times makes it harder to tilt and match concrete panels.
Every job is different when raising concrete, this is why it takes many of years and decades to fully understand how to raise sunken concrete and how to properly do the void filling process. Concrete lifting is not just about raising the sunken concrete it is also about filling all the voids too.
Polyurethane foam material is very flammable while installing the expanding material. If the installer makes too long of injections while installing the polyurethane foam material because of the heats that are involved with the chemical reaction process it can cause a fire.

Polyurethane Foam Fires That Have Happened In The Past (Click On Links Below For More Information)

See What Other Compaines Are Saying (Click On Links Below For More Information)

Google Polyurethane Foam Concrete Lifting Case Study (Click On Link Below)

Search for engineering reports on polyurethane slabjacking failure modes – Google Search

Experience of Raising Sunken Concrete With Mudjacking (Grout Injection) & Polyurethane Foam. Concrete Industry Experience Since 1984

Since they first started raising concrete with foam, there has been a rivalry over which is better for lifting concrete, Mudjacking or Polyurethane Foam. Mudjacking was first used to raise concrete around 1930’s, making it a proven method over a long period of time. Polyurethane Foam was first used to raise concrete around 1980’s, but it became more common only since 2010, making it a new method of raising concrete. When Polyurethane Foam companies talk about the benefits of foam, the main reason they say it’s so great is that it’s engineered, lightweight, sets fast, and is durable. What they don’t talk about are other important aspects that are needed to complete a concrete raising job. They don’t mention that foam can put a lot of pressure on a small area, causing unnecessary cracking. They don’t talk about how easy it is to over-lift a concrete pad or how difficult it is to fill voids under a concrete pad without over-lifting it. They also don’t talk about the difficulty of lifting a variety of jobs, and they don’t talk about the benefits of Mudjacking.

Two of the main complaints about mudjacking is that the grout mixture is too heavy for the soil conditions causing the concrete to sink again and the material deteriorates and washes away over time. If you ask Google AI, that’s what it will say about mudjacking grout material. Because my beliefs differ from Google’s AI, I asked AI how it came up with that conclusion. It stated that AI often projects an ideal scenario rather than other variables, such as on-the-job problems and applications. In other words, AI likes to talk about how effective it should be rather than how effective it is.

There are very few case studies examining whether the material is responsible for concrete resettling when raising residential driveways, sidewalks, and patios. The ones that exist are conducted by Concrete Lifting companies that just raise concrete with Polyurethane Foam, which claim the material’s weight is why concrete resettles. I have seen studies by the Missouri Department of Transportation on raising roads, with mixed reviews. Put into Google “Search for engineering reports on polyurethane slabjacking failure modes,” you can find these reviews. Some findings include that inexperienced operators can raise a pad too high, requiring further, often uneven adjustments. Another is that failing to properly fill voids can lead to localized support loss. There are also other problems that I haven’t mentioned. The problem is that roadways are very different from residential concrete. The soil beneath them is properly compacted, making both methods less likely to settle. The concrete is also much thicker, which allows both Polyurethane Foam and Grout material to travel farther, thereby filling a pad more effectively. I’ve mudjacked bridge approaches, which are typical of roadways, and found no issues with settlement, and I never raised them too high.

Owner Kurt Lummerding knows how well Mudjacking (Grout Injection) works and has been raising sunken concrete since year 2000, longer than foam has been used to raise concrete. I’ve paid attention over those years to how well Mudjacking works, which is a case study that is far more effective than looking at individual jobs. Even though I raise an abundance of concrete pads, it’s not that common to hear complaints about future settlement, although it does happen occasionally. If settlement from using a grout mix to raise concrete were such a big issue, and since I have the equipment to raise concrete with Polyurethane Foam and I know how to raise concrete with Polyurethane Foam, I’d be using it for most of the concrete pads I raise. In many ways, that would be a benefit to me. Concrete Lifting with Polyurethane Foam takes less equipment, less help, and if I do it the same as other companies, less time. All of these would make raising concrete much easier for me compared to Mudjacking. The problem is, I don’t see that many pads settle. At least not enough to call it a material problem. Besides, concrete pads also re-settle when Polyurethane Foam is used to raise them also. In fact, because many pads are never properly filled underneath after being raised with Polyurethane Foam, future settlement is highly likely. I’ve also seen concrete pads replaced, only for them to sink again. There is no question that it’s possible for a settling concrete pad to re-sink after being repaired. That can occur because the soil under the pad was never compacted properly when first installed and, as a result, takes years or decades to compact properly. Having a pad settle is proof that the soil beneath the concrete was never properly compacted.

Future settlement depends more on how well the soil beneath the concrete was compacted than the weight of the Grout material or the Grout material washing away. After all, in most cases, pads seldom sink more than 4 inches. Adding 4 inches of Grout mix under a concrete pad to raise it to its proper height adds very little weight compared to the weight of the concrete pad and the vehicles that drive on it. It’s the total weight of all these, along with how well the soil beneath the concrete was compacted, that has the greatest influence on whether future settlement occurs. The grout material I use is a sand, fine clay and cement mixture. The fine clay portion of the mix gives the material its structure and allows the grout mix to slide underneath the concrete and cement part of the mixture gives the grout mix added strength, the more cement you put in the mix the higher strength the mix is. This grout mix doesn’t wash away when mixed properly and can be higher strength then a Polyurethane Foam.

There are also other factors that can influence settlement, including how much water is allowed to drain under a concrete pad and the experience of the installer raising the concrete pad. When water is allowed to drain under a concrete pad, it can further compact the sub-base, especially if the ground under the concrete pad isn’t properly compacted. I’m sure most think water isn’t an issue but having improperly sloped landscaping away from the concrete pad and downspouts often drain near a concrete pad, water often has easy access underneath without being noticed, water can easily contribute to future settlement of the concrete pad. Then there’s the installer regardless of the method used to raise concrete, experience takes time and after a few years most installers think they’re experienced at raising concrete. That may be true for simple jobs, but many jobs are far from easy, even with experience. The truth is, learning how to raise all types of concrete pads, regardless of the method used, takes many years or even decades of practice to raise concrete properly and to learn how to fill voids properly. Unlike me, most companies don’t have that experience, and most companies hire employees to raise their concrete lifting projects. That results in many companies trying to raise concrete with inexperienced help, which minimizes quality and success. It also increases the chance of future settlement.

Although there are concrete lifting training courses for both Mudjacking and Polyurethane Foam, these courses are only a few days long, hardly long enough to effectively learn how to raise concrete. The rest of the learning takes place on the job, often with very little guidance from inexperienced supervisors. This results in pads being raised incorrectly and excessive voids left under pads, which can lead to future settlement, unnecessary cracks in pads, and not necessarily achieving the proper height. Companies often make excuses for the inability to raise a concrete pad back to its proper height, like the concrete was too heavy or the concrete was too thin or weak and was starting to crack and fall apart. Another problem why companies can’t raise the concrete back to its proper height is the installer not understanding when to cut the concrete slab to make free movement when the concrete is binding or understanding how to cut the concrete properly to achieve free movement. I’ve raised concrete pads that are 3 feet and thicker with no problems. I’ve also raised concrete pads that are thinner than normal with no problem. I understand when a concrete pad needs free movement and won’t raise because the concrete is binding. I achieve free movement in the concrete pad with variety of concrete cutters that cut different depths of concrete. Most excuses for not being able to raise a concrete pad back to its proper height aren’t valid but rather excuses for the lack of knowledge of the installer. When raising concrete, experience does matter.

Some pads are more prone to resettling after being raised, especially those that rest in the backfill zone, particularly when the concrete being raised is completed within the first few years of construction. This is because the backfill zone is never compacted properly, especially when the soil used to backfill a house is clay. The backfill zone is also the deepest area around a house to be backfilled, and it’s the area that is least compacted. That means the only way to ensure the soil is compacted properly is time, rather than anything else. As a result, concrete is more prone to settling again when it sits in the backfill zone compared to other areas, regardless of whether it’s Mudjacked, Foamed or Replaced. The house or building back fill zone or service trenches can take many of years or even decades to compact fully.

Caliber Mudjacking has many years of experience raising sunken concrete since 1991 with Grout Injection (Mudjacking) and Polyurethane Foam since 2012. Both methods have their place in the concrete lifting industry, and I treat them as a tool in my toolbox.

Jobs I raise concrete with Polyurethane Foam are heavy commercial and industrial concrete pads and interior concrete slabs with limited access. The reasons for this are because the weight of the heavy concrete slabs compresses the Polyurethane Foam as its being lifted which doesn’t allow the concrete pads to lift as fast causing a more controlled lift. Voids are being filled properly because of the heavy weight of the concrete slab and compression of the Polyurethane Foam material as its being lifted, which allows the Polyurethane Foam material to travel farther underneath the concrete and distribute the Polyurethane Foam material everywhere underneath the concrete slab filling the voids. Raising Interior concrete slabs that have limited access with Polyurethane Foam is sometimes the only method that can be used. Sunken residential concrete pads don’t usually fall into either of those categories because how light and easily the concrete is lifted when it comes to driveways, sidewalks, patios, and garage floors.

When lifting concrete pads and if left with large voids underneath the concrete after the concrete is lifted, the concrete can experience stress that leads to future cracking and settlement, and in some cases, replacement is the only option for repairing it. Voids underneath the concrete also make it easy for water to drain under the concrete pad, which can result in heaving in the winter or increase the chance of future settlement. If the concrete pad happens to be in the backfill zone of a house, voids that are left unfilled can easily allow water to drain to the weeping tile, which increases the chance of a leaky basement or structural issues. For these reasons, I like to ensure concrete pads are filled properly, and Mudjacking (Grout Injection) is the only method that can achieve this properly for most residential concrete lifting.

Another advantage of Mudjacking is when the concrete is being lifted it rests on a layer of soft grout material while being installed because of longer set up times, this allows the concrete pad to be floated to its proper height. The benefit is that the concrete pad can move slightly lengthwise or sideways as it’s being raised, which is often needed to prevent cracking and achieve the proper height. Having the concrete pad rest on a soft layer of grout while the concrete pad is being lifted also allows the concrete pad to flex, which helps reduce the chance of cracks. It’s also easier to move around the concrete pad from hole to hole quickly with Mudjacking, this allows the concrete pad to be raised more evenly, again reducing the chance of cracking. The grout material also doesn’t expand and is more controllable which makes it far easier to fill voids and obtain the proper height. There are many benefits to Mudjacking, and experience allows me to raise a much wider variety of jobs.

Raising concrete with Polyurethane Foam has very few of those qualities, when you inject foam into a hole, it expands and sets up instantly within 15 mins. That doesn’t allow the pad to float or move sideways. It can also put pressure on one small area of the concrete pad, often leading to unnecessary cracking. The closer one gets to the proper elevation, the harder it is to know how much foam to inject. Pumping too much foam into any hole could raise the pad too high, and not enough foam will not allow it to travel, which is needed to fill voids. Not only is it time-consuming to try to fill a pad with foam, which can lead to over-lifting, but it also can become very expensive given the amount of foam it takes to fill a concrete pad properly and the labor cost from the time it takes to raise and fill voids best as possible by practicing patience while installing the expanding Polyurethane Foam material.

Because jobs vary so much and many installers lack knowledge, making excuses is very common in the concrete raising business. Caliber Mudjacking Ltd doesn’t make excuses. Caliber Mudjacking Ltd always make sure you get the best possible results, back by industry leading experience and knowledge raising your concrete back to its proper height and filling voids properly with the fewest problems compared to other concrete lifting companies, whether they are using Polyurethane Foam or Grout.