Concrete flooring is one of the oldest and most widely used long-lasting and durable floors. However, fractures, gaps, and fissures can occur and eventually lead to massive cracks in your concrete floor slab. However, how can you repair cracks and gaps in your concrete floor, basement, or garage floor?

Determine the type of crack and its cause before attempting to repair concrete flooring cracks. Clean the area, mark it with a marker, then fill it with concrete floor fillers. Once completed, seal the area and take precautions to prevent a crack from recurring in your concrete patio, basement, or garage flooring.

Identify the cause of concrete cracks, how to repair such cracks and gaps, and what preventative actions you may do to lessen the likelihood of your concrete floor cracking.


What Causes Concrete Floor Cracks?

Identifying the roots of cracks in a concrete floor is the most important step in repairing it. Drying shrinkage is a typical cause of concrete defects. It is the point at which plastic concrete sets, hardens, and begins to shrink by 12.5 percent for every 20 feet. All of the factors that promote drying shrinkage can also induce and exacerbate concrete cracking. Furthermore, when the internal tensile stress of the concrete exceeds the tensile strength of the concrete, gaps and fissures might occur on your concrete floor.

Some of the reasons why your concrete surface may develop cracks are as follows:

  1. Too much water in the concrete mix produces additional drying shrinkage when the extra water evaporates, increasing the likelihood of cracks appearing on your floor.
  2. Subpar subgrade- In order to construct a good base for your new concrete surface, you must provide correct sub-grade preparation, with a smooth, uniform, and frost-free sub-grade being advised if you want to avoid concrete settling and cracking. A well prepared, smooth subgrade reduces pressure during concrete shrinking, which prevents cracking.
  3. Improper concrete curing- Improperly cured concrete is prone to breaking at an early age. Concrete curing is often conducted to aid with moisture retention, hence minimizing fast moisture loss, which causes cracking. As a result, if the procedure is not done properly, the concrete surface is prone to map cracking, which occurs when the surface concrete shrinks quicker than the concrete underneath the surface owing to rapid drying. Severe concrete floor cracks caused by inadequate curing generally necessitate repairs because they might damage the structural integrity of the floor. Curing also aids in the prevention of concrete scaling.


Is Cracking in a Concrete Floor Slab Normal?

Yes, concrete floor slabs crack on a usual basis, often by 0.5 inch for every 100 feet. As a result, there's no need to be concerned if you come across very small (0.125-inch-wide) slab defects. However, if you see fissures that are substantially wider than 0.125 inches, the structural integrity of your floor slab may be affected, and repair work may be required.

Concrete slab cracks are classified into three categories.

  • Plastic shrinkage cracks,
  • Drying shrinkage cracks,
  • Structural fissures

It's essential to comprehend which kind of cracks are most likely to form on your slab, as each has its own set of management procedures.


How to Repair Concrete Floor Cracks

You can repair cracks in your concrete patio, basement, and garage floor without spending a lot of money. It's essential to repair any major cracks in your patio and garage floor as soon as they develop. This will assist prevent cracks from widening into major gaps and holes, which can have a severe impact on the structural integrity and floor durability of the concrete. Furthermore, cracks are unsightly and detract from the aesthetic value of the floor. Repairing them, on the other hand, goes a long way toward increasing the value and general appeal of your property.

Here's a quick and easy DIY method for fixing shrinkage gaps in concrete floors:

  1. Scrub the Cracks in the Floor Section

Dirt and debris including oil or grease can reduce the effectiveness with which concrete filler material binds with cement.

  1. Close the Crack Hole

This can be accomplished by cold chiseling the crack's base to make it bigger than the surface. This enhances the bonding effectiveness of the filler material to the old crack.

  1. Vacuum or sweep the floor

Sweep the area to remove any dirt or debris. To fully remove any dirt and dust particles that may impact the hole and crevice repair, use a soft broom, a dry mop, or a vacuum cleaner.

  1. Fill the cracks in the concrete floor with concrete floor crack filler.

Apply the concrete filler along the crack's length. After the filler material has settled, smooth up the concrete surface using a trowel. Allow the filler material to dry overnight.

     5. Seal the Repaired Concrete Floor Area

Seal both the filler/patch and the concrete as a last step to avoid stain absorption by the concrete material. Use a high-quality sealer (Armor Solvent Based Acrylic Sealer) or a water-based polyurethane sealer.


Filling Large Gaps on Concrete Floors

Wide cracks, as opposed to smaller cracks, are best repaired with concrete patching cement. To blend with the surrounding floor, the pathing compound is mixed with water and applied with a towel, smoothed, and textured. It is then painted and sealed to match the current flooring.

You will need the following tools:

  • Masonry chisel
  • Masonry hammer
  • A wire brushes
  • Patching compound for concrete

Here's how to repair large cracks on your concrete floor.

  • To allow for disruption, remove any furnishings. Thoroughly clean the area.
  • Using the chisel and masonry hammer, chisel the crack to expand the gap.
  • Remove any dirt and debris from the area using a wire brush. You may vacuum the area to eliminate any remaining water and debris.
  • Get your concrete repairing compound (such as EPOXY Mortar Patching System) Mix the pathing compound and trowel it into the holes or cracks. Stab to eliminate any remaining air pockets until the gaps are completely filled.
  • Smooth and feather the patching compound, then brush off any debris and let it cure fully.
  • Paint and seal your concrete floor in the color and tint of your choice.


How Do I Prevent Concrete Floor Shrinkage Cracks?

Preventive treatments against cracks in concrete floors can be implemented during the concreting stage or after the concrete has been formed. Here's how to keep concrete floor cracks:

  1. Assuring that there is no extra water in the concrete – because the water-cement ratio impacts the quality of concrete, an appropriate water/cement ratio that should not be exceeded during concreting is 1/2. Concrete with a lower water content has a higher durability.
  2. Ensuring that the right concrete mix design is used, which includes using the necessary amounts of concrete aggregates for lower-shrinkage concrete. This also entails utilizing the appropriate amount of cement in the water/cement mix.
  3. Using high-quality concreting materials – your aggregates should be thick, firm, large top sized, and have ideal gradation. Using high-quality aggregates helps to reduce concrete shrinkage. Low-quality admixtures, such as filthy aggregate, with increased water needs, on the other hand, tend to worsen concrete shrinkage.
  4. Using the correct finishing techniques- Proper timing is normally essential in between concrete finishing processes as this might impact the risks of cracking later on. Furthermore, high finishing processes like as flat troweling and flat floating are required. Among the finishing procedures to avoid are:
  • Using vibrating screeds to overwork the concrete, which causes aggregate settling.
  • Finishing in areas with surface bleed water, as this increases concrete cracking.
  • Ensuring adequate concrete vibration - properly vibrated concrete is typically devoid of any entrapped air that might contribute to the formation of fissures later on.
  • Contraction joints, which are plastic or hardboard strips that are simpler to repair than concrete floor fissures, can be installed. Contraction joints are often built at strategic depths and at specific points, taking into consideration the slab thickness, to provide maximum efficacy in the prevention of random fissures.