How to Finish Concrete like a Pro
Regardless of what type of concrete project you are contemplating on doing you need to know the basics. Concrete finishing is very much like smoothing out frosting on a birthday cake. It does look better when someone does it that has a lot of experience but it also turns out good with a little practice by even the complete novice. This may be over simplified but it gets the point across that it isn’t rocket science.
The first step is pouring the concrete into your prepared forms. This doesn’t just involve discharging the concrete from the truck to the ground but includes methods to ensure that the concrete you are pouring will not for air cavities during the pour that can weaken your finished product. This is done by agitating the poured concrete from the top down to remove these air bubbles. Some pros go as far as the use a power agitator for this task. For smaller residential applications the process of screeding he concrete can accomplish this.
Screeding takes two in most cases. One person on each end of a screed board will do. The board is rubbed back and forth and towards one end of the forms. This causes the concrete to compact in the forms and also helps remove those air pockets. As the board passes over the two tops of the forms a rough surface develops.
Once the concrete has been screeded and a uniform flat surface appears it is time to “float” the surface. For a large and hard to reach pad using a bull float will do the trick. These bull floats incorporate sections of threaded handle that can be put together to reach quite some distance. The bull float takes some practice to get used to it and does its trick on when it is pulled back across the surface that you are finishing. Bull floats can be rented for about $20 per day and are essential if natural arm reach is not going to be enough.
Smaller surfaces may require a regular float or Mag. The term Mag refers to the magnesium that is used in some of these tools. These tools are best used in a light semi circle action or arc. The purpose of both the Mag and bull float are to smooth the surface beyond what the screed board is capable of. The concrete gets a wet look on the surface when conditions are best to trowel.
After putting a smooth troweled finish on the concrete it is now time to use and edging trowel or tool to round off the corners of the concrete to prevent cracking and make the project look more professional. This would also be the time that sections of sidewalk would be etched across at even distances to prevent large cracks from forming. There is also a specialty tool for this task. Unsure about just how far apart the pros would do it just take a look at your neighborhood sidewalks for ideas on distance between sections.
Now that we have done all of that fussing and gotten a pretty smooth surface to our concrete we are going to now want to rough it up a bit. This is done on surfaces that are going to be walking surfaces and the purpose is to prevent slips due to your mastery of mag and float. This is simply done by using a stiff push broom to leave its texture behind as it is passed over the surface. Ideal conditions for brooming would be when concrete is beginning to set up and you can lay your hand on top of it without your hand sinking.
O.K., now we must be done, right? Wrong, because now is one of the most crucial parts of finishing concrete that is going to last and last. We need moisture and preferably cool temperatures for the concrete to cure to a granite hard strength. Ideally, you would not pour and finish concrete on extremely hot days. To ensure that the concrete does not dry out too quickly plastic sheets can be placed over the curing concrete and water should be sprayed under the plastic sheeting to keep the surface moist for 3 days. Once the 3 days are past, remove the covering and use. After 14 days and before 20 days be sure to buy some concrete sealer and apply according to manufacturer’s instructions.
Most of the tools needed are relatively inexpensive to rent or to buy. But remember that the only thing that usually can ruin good concrete finishing tools is not cleaning them off before the concrete dries
That’s it. You can make it look like a pro lives there! Good luck.
