• Fix the crack in your concrete garage or basement floor yourself by following these step-by-step directions. Using a diamond blade on your circular saw, cut a 1/2-in.-deep groove along each side of the crack. Wear an N-95 respirator and turn on a fan to blow the concrete dust out of the garage.
• Concrete floor patching is your solution to minor cracks that are more about aesthetics, moisture intrusion, and insect infestation than about major structural integrity. Cracks make your basement look bad and they do not help your property's resale value.

• Fix Cracks In Concrete Basement Floor
• Fix Cracks In Concrete Floor
• Fixing Cracks In Concrete Slab
• Fixing Large Cracks In Concrete Floors
• Repair Small Cracks In Concrete Floor

Wide cracks in concrete are best patched and sealed with a concrete patching compound. Smaller cracks, less than 1/4 inch wide, can be repaired with a concrete caulk or liquid filler. Patching compounds typically are mixed with water and applied with a trowel. They have a texture similar to grout and can be smoothed and textured to blend with the surrounding area. However, the color of the patch will look like new concrete and will not match the old concrete. Hiding the patch completely requires painting the surface with an appropriate concrete paint.

How to Repair Wide Concrete Cracks

Basement floor cracks can be repaired with an epoxy floor crack repair material. A diy basement crack repair kit is the best way to fix cellar floor cracks.

The secret to fixing wide concrete cracks is to undercut the sides of the crack to give it an inverted 'V' shape. This helps the repair material to 'key' into the crack, creating a mechanical bond in addition to the chemical bond between the patch material and the concrete.

1. Chisel the crack with a hammer and masonry chisel to widen the base of the crack and to dislodge any loose material from the old concrete.
2. Remove all debris from the crack, using a wire brush. If desired, clean the crack with a pressure washer or a garden hose and spray nozzle.
3. Remove all water and debris from the crack with a wet/dry shop vacuum or a brush. Work carefully to remove all dust and grit from the crack. It's OK if the surfaces are wet, but there should be no pools of water.
4. Mix the concrete patching compound, following the manufacturer's directions.

1. Trowel the compound into the crack. Stab the trowel into the compound to remove air pockets and help work the patching material deep into the crack. Fill the crack up to the surrounding concrete surface.
2. Smooth the surface of the patch with the trowel, feathering the compound into the surrounding concrete.
3. Brush the surface of the patching compound with a dry paintbrush to texture the surface, if desired.
4. Let the compound cure as directed.
5. Paint or seal the surface of the patch and surrounding area, if desired.

How to Repair Narrow Concrete Cracks

Narrow concrete cracks can be filled using masonry crack elastomeric filler that can be applied with a caulking gun. Alternatively, many products come in bottles with an applicator tip. Very small cracks, such as hairline cracks, can be repaired using a vinyl concrete patching compound applied over the crack and then smoothed with a putty knife or trowel. For hairline cracks, applying repair caulk or crack filler over the cracks usually is not effective, as the caulk tends to peel off of the surface over time.

Narrow cracks can be deep, often extending through the entire thickness of the concrete slab. Therefore, it's a good idea to start the repair by stuffing foam backer rod into the crack to create a base to hold the repair material. Backer rod is solid in a variety of sizes; use a rod diameter that is slightly larger than the width of the crack. Stuff the backer rod into the crack with a screwdriver to a depth of 1/4 inch. Fill the crack with the repair material, following the manufacturer's directions.

Concrete flooring will eventually crack. Only the most expertly laid concrete will steer clear of cracking, and even then you're only buying yourself extra time. Factor in additional stresses, such as tree roots, shifting ground, earthquakes, flooding, rising water tables, and the weight of heavy appliances, and the concrete cracking will begin sooner rather than later. Basement floors especially are prone to cracking since they are below-grade areas and thus are closer to tree roots and water tables. It doesn't help that some basement concrete floors are poured quickly and without much attention paid to quality.

Concrete floor patching is your solution to minor cracks that are more about aesthetics, moisture intrusion, and insect infestation than about major structural integrity. Cracks make your basement look bad and they do not help your property's resale value. Rising water can find its way through cracks. Carpenter ants, termites, and even vermin can find their way through cracks. When you patch a cracked concrete slab, your work will look like a patch. It will not blend it with the rest of the floor unless you paint and seal the concrete.

The great thing about concrete patching is that it's an easy job and requires few materials. Not only that, the materials and tools are inexpensive.

Tools and Materials

• Concrete or mortar chisel, not a wood chisel
• Wooden paint stirring stick
• Concrete bonding adhesive, like QuikRete Concrete Bonding Adhesive
• Concrete patch compound like DAP 31084 Concrete Patch Interior and Exterior 1-Quart, an inexpensive, easily available concrete patch material
• Large sponge
• Wire brush
• Shop vacuum
• Safety glasses
• Trowel or large putty knife

Remove Chunks of Concrete

Begin by running your chisel through the crack to remove any obviously loose chunks of concrete. Pull them from the crack with your fingers, if possible, or by knocking them free with a dull screwdriver.

Taper Down the Crack

Use the chisel and hammer to taper down the sides of the crack. This may seem counter-intuitive, but you need to get rid of the unstable edges of this crack and get down to the more solid material. Chipping out the good concrete in these initial stages may give you some pause. But you'll sometimes find that this good concrete isn't so stable after all. Be careful of extending the taper too far, though.

Clean out the Crack

Use a wire brush and a shop vacuum to clean out all the debris from the crack. The crack needs to be completely clean and free of chunks, pebbles, dirt, dust, weeds, and anything that might hinder the adhesion of your patching material.

Apply the Bonding Adhesive

Brush on a bonding adhesive to the entire crack. Let the adhesive thoroughly dry. Concrete bonding adhesive eliminates the need to roughen up the surface for the new concrete to adhere.

Mix the Concrete Patch Material

Mix up your concrete patch material. Do not use ready-mix concrete such as Quikrete as this is not suitable for patching. Instead, buy a material designed specifically for patching concrete.

Apply the First Layer

Push the concrete patch compound into the crack as far as possible with a paint stirring stick. Make sure that no voids remain in the patch material. Let this deep, below-grade patch material thoroughly harden. The idea with this first layer is to occupy large areas toward the bottom of the crack. Do not bring the patch material up to the level of the concrete floor yet.

Fix Cracks In Concrete Basement Floor

Apply the Second Layer

Fix Cracks In Concrete Floor

Trowel your next layer of concrete patch compound to bring the patch up to grade. Smooth out the patch with the flat face of your trowel. To further smooth out your work, use a wet sponge while the patching material is still wet. If you wait until the material has dried, it is not possible to work with the material any longer.

Fixing Cracks In Concrete Slab

Let the Patch Cure

Cover the area with plastic and weigh it down so that it does not blow away. Let it cure for three days or for the period recommended on the product packaging.

Fixing Large Cracks In Concrete Floors

An Alternative for Narrow Cracks

Repair Small Cracks In Concrete Floor

Thin cracks in concrete that are less than 1/4-inch wide are even easier to patch. Purchase a liquid concrete patch repair, such as Liquid Nails Concrete Repair or Quikrete Acrylic Concrete Patch. These watery repair materials are superb for narrow cracks as they conform to the crack.