Concrete cracks. That's nearly a fact of life. Only the best concrete work will steer clear of cracking. But just give it enough time—it will crack.
So you need to know how to repair a concrete floor. "Patch" is more the word, because it's impossible to truly stitch together a cracked concrete floor.
The great thing is that it's an easy job, requiring few materials. Not only that, the materials (and tools) are inexpensive.
Difficulty: Easy
Time Required: 2
Here's How:
- Use a mortar or concrete 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 more solid material.
- Use a wire brush and Shop Vac to clean out all the junk from the crack.
- Brush on a bonding adhesive to the entire crack. Let the bonding adhesive thoroughly dry.
- Mix up your concrete patch material. Do not buy a bag of ready-mix concrete and expect to use this for patching. Instead, buy a material designed specifically for patching concrete.
- Push down the concrete patch compound into the crack as far as possible with a paint stirring stick. Make sure that no voids are in the patch material.
- Let this deep, below-grade patch material thoroughly harden.
- Trowel on the 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.
- Cover area with plastic and weigh it down so that it does not blow away. Let cure for 3 days.
Tips:
- Chipping out the "good" concrete in the initial stages may give you some pause. But you'll soon find that this "good" concrete isn't so good. It's probably quite unstable.
- For the concrete patch, I recommend Dap 31084 Concrete Patch Interior and Exterior 1-Quart. It's cheap and widely available.
- Why use concrete bonding adhesive? This eliminates the need to roughen up the surface for new concrete to adhere.
- Alternatively, you can squirt some Liquid Nails Concrete Repair into the crack. But be forewarned: this is nothing more than super-strong caulk. It will do nothing to cover up the crack.
- Warning: this type of patch is not appropriate for basements. You'll need to use hydraulic patch compound for basements.
What You Need
- Concrete or mortar chisel
- Wooden paint stirring stick
- Concrete bonding adhesive, like QuikRete Concrete Bonding Adhesive
- Concrete patch compound, like DAP 31084
- Large sponge
- Wire brush
- Shop vacuum
- Hammer
- Safety glasses
