How to Level a Concrete Floor or Driveway Using a Bull Float
Making the Concrete Floor or Driveway Flat
So you are ready to take on the job yourself. You know exactly what you want done. You have it all laid out. The concrete has been poured. Now for the fun part: Leveling off the concrete floor yourself....
I have installed concrete in West Virginia for many years, so I know being prepared for the job can mean the difference between an easy, nice finish and the biggest mess imaginable. Seriously: Not finishing this job in a timely manner could easily mean you are tearing back up your concrete and starting from scratch.
What You'll Need
First, you are going to need a basic set of hand tools for the job. In addition to your shovel, hoe, and rake, these tools will help you place and begin the actual finishing process of the concrete itself. For the flat work you are going to need:
- Level. Levels come in many lengths, and for sidewalks and small areas, a 2-foot level should be fine. Bigger jobs require a bigger level. A 4-foot level almost always works, but you can get one up to 8 feet long if you need it.
- Strike-Off Board (aka the SOB, lol). The strike-off board can be a straight piece of lumber, usually a 2x4, or a specialized piece of aluminum. The SOB should be long enough to span between your leveling points and light enough to move with your hands.
- Bull Float. A bull float is used to smooth out the concrete. Wider and longer is usually better for a smoother surface.
- The oldest and most common tool for striking off is a trusty old 2x4. The 2x4 should be straight and have a smooth surface. You could even paint or seal it to make it smoother and help keep the water out.
- Another choice, the one chosen by most contractors today, is an aluminum strike-off board. An aluminum SOB (still loling) is preferred because of its consistent straightness which keeps it far more accurate. It's less likely to bend or warp because it doesn't absorb water, either.
Once you've chosen your tool, the fun begins. The smooth surface some finishers achieve yet some never accomplish is a daunting task! Performing a good strike off is a higher art. Even after years of practice, some people just don't get it.
In order to be good strike-off artist, you must visualize how your board is going to move and spread or place the concrete. "Wet screeding" is also part of this process. Being able to screed off the concrete without hitting those elevation marks or the form takes practice.
- In order to accomplish a good strike off, the leading edge of your SOB should be just above the actual finished plane of the floor. This allows excess concrete to flow under the strike-off board and fill in the uneven gaps like a grader would even a road.
- For this reason, several small passes will be more effective than one hard pass. Hard passes that move a lot of concrete causes concrete below the finished plane to be moved, too. This will result in your finished floor being too low or uneven.
- When you're finished striking off, you should have a fairly flat surface with a few minor ups and downs that can be easily corrected with a bull float.
Finishing up With a Bull Float
Time to finish smoothing out the surface and make it nice and flat! That's exactly what the bull float was made for. Those small ups and downs you left after using your strike-off board will come out easily with a bull float, providing you haven’t let the concrete sit and dry too long.
Bull floats are commonly available at any hardware store and come in a variety of different styles, lengths, and materials. Most commonly available in aluminum and magnesium with rounded, squared edges, and handles that easily adjust or stretch. Most contractors prefer the 45-inch float with squared edges for concrete floor situations.
- Immediately after striking off, start using your bull float.
- Keep the float at a low angle (almost flat to the surface). Otherwise, you will ruin your strike off by pushing concrete ahead of your float.
- If an area is just a tiny bit low, you can "juke" or shift some concrete over by gently but quiclky shaking the float over the concrete. This will cause the concrete to sort of liquefy and move towards the lower area.
- Once you're done with the initial bull float pass, you are going to have to touch up those edge marks with a second light pass after the concrete floor has somewhat stiffened. The stiffer concrete will help keep the surface smoother as you float it out.
- The next steps will be waiting for the initial setting and the "bleed water" to evaporate so you can trowel, edge, and joint.