Slab jacking, also known as mud jacking, is a way to level concrete. It can help you save time and money. Instead of having your sinking concrete sidewalk, patio, or floor completely redone, there is a possibility you can hire a professional slabjacker to fix the problem.
Why Does Concrete Sink?
Before we get into slab jacking, let’s look at the main reasons why concrete sinks. If the concrete has been poured on a substandard foundation (fill dirt was used and the builder didn’t compact the dirt properly) or it hasn’t been reinforced with steel, the concrete could possibly crack and sink. The sinking happens when a pocket of air or water, usually referred to as a void, develops under the concrete. Water erosion, natural settling of the soil and the growth of tree roots can all create these voids.
In order to avoid these problems in the future, the next time you have concrete poured, use a superior filling material for a foundation–such as sand or sand and gravel mix. Also, make sure the foundation is compacted properly to remove air and prevent the settling that can occur anywhere within the next few months or several years.
How is it Done?
If your concrete has large sections that are deteriorated or are crumbling, your only option is to replace it. Otherwise, slab jacking can raise almost any block or slab. Here is how they do it.
To start with, a series of holes about one to three inches in diameter are drilled in the concrete slab in a set pattern. Holes that are too large can weaken the block and cause cracking if the grout mixture flows too quickly. Smaller holes are best and most slabjackers have refined their techniques to use them.
Next flexible hoses are run from either a portable pump or a pumping truck and placed in the holes. A specialized grout mixture is then pumped slowly into the holes. The voids under the concrete fill up and the grout mixture will become pressurized, hydraulically lifting the slab. The mixture varies, but it can contain limestone, sand, cement, fly ash and additives to prevent shrinking. At the end of the job, the holes are patched with concrete.
I would like to add that this procedure should only be attempted by a professional slabjacker. This is not a do-it-yourself project. Mistakes can result in further property damage and, in some cases, injury.
The Benefits of Slab Jacking
There are several benefits to using this method of concrete leveling. First, the cost will be at least 50 percent less than what it would cost to demolish and replace your concrete slab. It takes less time too. In just a few hours your slab could be raised and ready for use. If you wish your surrounding landscape to remain untouched, there will likely be little or no disruption to it.
Another benefit to hiring a slabjacker to repair your concrete slab is that in most areas they are not required to get a municipal building permit. Also, slabjackers can work in almost any weather. The only exception to that is if they use a material that is mixed with water and are pumping outdoors during the cooler months. Freezing cold temperatures can cause problems with their slab jacking equipment.