How to fill the void under a concrete driveway?

The article aims to answer the question “How to fill the void under a concrete driveway?”. The article will also discuss the best possible method for you to use depending on the size of the void underneath your concrete. 

How to fill the void under a concrete driveway?

• There are several ways to use polyurethane to fill voids under concrete driveway such as cracks, holes, and gaps. It may compact organic matter, sand, and rock fragments. 

• Polymer injection, when done correctly, may offer support without raising or straining the slab to the point where fractures occur.

• In the case of a home, a typical void fill application would be beneath the front door. Rebar is often used to “pin” them to the foundation wall. 

• Some significant settling may be caused by fill material that is often utilized around the foundation, as well as by gutters and downspout locations that are incorrectly fitted on new construction. 

• The entrance will begin to settle if it isn’t nailed down firmly to the foundation. A vacuum will be created beneath the entrance if it is anchored to the foundation. 

• As time passes, the rebar that holds the door in place will either flex or eventually corrode and shatter.

• Other compounds, such as soil stabilizers, may be used to harden deeper layers of soil, but their expense makes them unsuitable for domestic work, therefore they’re more often seen in municipal and commercial settings.

• Concrete slab maintenance, whether residential, commercial, industrial, or municipal, necessitates knowing how to deal with voids, both static and dynamic.

What do I need to fill the void under a concrete driveway?

• Drill
• Concrete slabs
• polyurethane 
• Polymer injections 

Can I use geo-polymer to fill the void under a concrete driveway?

No, You can’t use geopolymer void filling to fill deeper layers of compacted fill thus you’ll have to use polymer injection to stabilize and densify the fill.

Cracking and/or sinking concrete may occur as a result of voids beneath concrete. Soil support, anchors, rebar, or Sonotube usage all contribute to the formation of cavities in concrete. A gap forms between the earth and the bottom of the concrete slab when it settles or is somehow moved away, causing the slab to lose support.

Fill dirt, erosion, burrowing rats, rotting organic waste, and even a lack of moisture in the soil may cause gaps in the foundation. 

Once they’re there, it’s hard to fill them back in. Smaller slabs such as pathways may be filled with gravel or sand, while bigger slabs such as driveways or patios cannot be filled with gravel or sand. 

These need a mechanism that does not elevate the slab, but rather supports it. Using an expansive polymer for void filling is useful for a number of reasons, including:

Can I use polyurethane foam to fill the void under a concrete driveway?

Yes, Injections of polyurethane foam are far less expensive than tearing out concrete slabs or redoing the driveway entirely. Additionally, there is little indication of the work that was done other than a rebuilt and level driveway. 

For residents in and around Alpharetta, Georgia, Advance Concrete Lifting & Leveling has an option for a concrete driveway solution.

The polyurethane foam is injected into the slab via tiny holes drilled on the surface, expanding and filling up the space. In order to prevent future soil movement or erosion, the substance is intended to cling to and adhere to the current soil.

Gravel is another ideal sub-base material for a concrete slab because of its strength and flexibility. To lay gravel, the soil must be prepared beforehand; pouring concrete straight upon rock is not recommended. 

As long as the gravel is clean and of a consistent size and shape, any kind of gravel may be used as a subbase.

Removing the concrete driveway would need a practice known as slab jacking in order to fix an issue that can be fixed by jacking up the earth. You don’t have to remove the driveway’s surface slabs or spend a lot of time reinforcing the structure.

How to fill the void under a concrete slab?

• Sloping sinkage and concrete cracking are both caused by voids in your concrete. If the supporting soil is weak or compressible, concrete will sink. 

• This might also be caused by a lack of effective drainage under your concrete, which allows water to build up. Soil underneath a slab can’t maintain its weight, thus it sinks or cracks depending on how much pressure is produced by an above slab.

• A portable pump and flexible hoses are used to pump a particular mixture into holes drilled in your concrete slab as part of the jacking process.

• When compared to removing and replacing your concrete slab, this is a more convenient and mess-free option.

• As a result, it helps keep your slab in good condition while also adding to its strength. Stable footing is provided by this structure. In addition, the color of your concrete is preserved.

• Slab replacement produces a lot of noise and garbage. Dust and debris are generated as concrete is broken apart. A landfill will be needed to dispose of the slab that is to be replaced.
• No demolition or re-landscaping will be necessary since the area around the project site will not be significantly impacted.

• Any kind of weather will work for this repair.

• Drilling four holes in the slab with a masonry bit on a drill is required. Depending on the size of the slab, the number of holes may vary. At least one or two holes are needed in the center of a smaller slab. In contrast, larger slabs may need the use of up to three holes.
  
• The thickness of the slab also has an effect on the distance between the holes you drill. There are a variety of methods for drilling the holes, but the most common is to drill three to eight at a distance of no more than one foot from the edge. 

• The holes are typically 1 to 2 inches in diameter and positioned such that they are in important locations.

Conclusion

A ‘void’ is the gap between a concrete slab and the ground. It is common for a gap to appear at the end of a driveway or path leading to a property. When you walk on concrete, you may sense a void under your feet, and you may feel it sag. It is clear that there is a gap in this world. 

In order to reinforce the concrete and prevent it from cracking and fracturing, drill tiny 5/8″ holes in the surface and inject our polyurethane foam into the holes. A polyurethane coating is applied to the concrete slab’s edges.

Frequently asked questions (FAQS): How to fill the void under a concrete driveway?

How to fill the void under a concrete driveway?

There are several ways to use polyurethane to fill voids under concrete driveway such as cracks, holes, and gaps. It may compact organic matter, sand, and rock fragments. 

Polymer injection, when done correctly, may offer support without raising or straining the slab to the point where fractures occur. In the case of a home, a typical void fill application would be beneath the front door. Rebar is often used to “pin” them to the foundation wall. 

Can I use geo-polymer to fill the void under a concrete driveway?

No, You can’t use geopolymer void filling to fill deeper layers of compacted fill thus you’ll have to use polymer injection to stabilize and densify the fill.

Cracking and/or sinking concrete may occur as a result of voids beneath concrete. Soil support, anchors, rebar, or Sonotube usage all contribute to the formation of cavities in concrete. A gap forms between the earth and the bottom of the concrete slab when it settles or is somehow moved away, causing the slab to lose support.

Bibliography

Bag of concrete. how to fill a void under a concrete slab (DIY). Retrieved from: https://bagofconcrete.com/how-to-fill-a-void-under-a-concrete-slab-diy/