You can't truly "level" concrete after it's completely set; the process needs to happen while it's still plastic and workable. What you're likely asking is, "How do you level newly poured concrete before it sets?". Here's how:
The process of leveling newly poured concrete is typically referred to as "screeding." Screeding ensures a smooth and even surface before the concrete hardens.
Here's the general process:
- Pour the Concrete: Distribute the concrete evenly across the area you are working with.
- Screeding: Use a straight board (a 2x4 piece of lumber works well, ensure it's not bowed). The board should be longer than the width of the pour.
- Motion: Use a sawing motion, work the board back and forth while pulling it across the concrete. This removes excess concrete and fills in low spots, creating a level surface. Overlapping passes are helpful.
- Initial Float: Once screeded, use a bull float (a large, flat tool on a long handle) to further smooth the surface and embed aggregate just below the surface.
- Edging and Jointing (Optional): Use an edger to create rounded edges and a jointer to create control joints (grooves) to prevent cracking.
- Final Float or Trowel: Depending on the desired finish, use a hand float or trowel to achieve the final smooth surface.
What if the Concrete is Already Set and Uneven?
If you're dealing with concrete that has already set and is uneven, you have a few options, which are more involved than screeding:
- Grinding: Concrete grinders with diamond grinding wheels can be used to remove high spots and create a more level surface. This is messy and requires specialized equipment.
- Self-Leveling Concrete: A self-leveling concrete overlay can be poured over the existing surface. This requires careful preparation and priming of the existing concrete. This overlay is designed to flow and find a level.
- Mud Jacking: If the concrete slab has settled unevenly (leaving one area higher or lower than the others), mud jacking (or slab jacking) can lift the slab back into place by pumping a slurry material underneath it.
- Demolition and Replacement: In severe cases, the best solution might be to demolish the existing concrete and pour a new slab.
It's essential to address uneven concrete slabs, as they can pose safety hazards and detract from the aesthetics of your property. Choose the appropriate method based on the severity of the unevenness and the desired outcome.
