How to Finish at A Residential Patio?

Have you ever seen a patio poured with new concrete and watched someone finish the concrete? You probably didn’t pay a lot of attention but you noticed someone down on their hands and knees with a trowel moving around the concrete surface. Like everything else that is done by someone with experience, it looked easy. It’s not that easy unless you have done some homework. So consider this your first lesson. If you haven’t done this before or only done it, a few times you are likely to make two mistakes; troweling too soon and troweling too much. Both of these have the effect of pulling fines and water to the surface. This can lead to a weakened surface, tiny cracks, and a white dusty surface. After thoroughly mixing the concrete, pour it into the forms slightly overfilling them. Then take a straight board (a 2×4 piece of lumber works great as long as it isn’t bowed) and simply level off the concrete.

Using a board that is longer than your pour is wide and using a sawing motion work back and forthuntil the concrete is level. You really need someone on the other side to help with this part. This is called “screeding” if you are trying to learn new words with which to impress your friends. Then with a wooden trowel or magnesium float if you want to get fancy, smooth off the surface. This should only take a few minutes. Do not try to turn this into a masterpiece-leave that for art class. This step is simply to put a relatively smooth surface on the concrete. When you are done, go clean your mixer and tools and get something to drink. Keep an eye on the concrete. The first thing you will notice is that some bleed water will come to the surface. This is a good thing. Allow all of the water to disappear before you do anything else. This can take 20 minutes or 4 hours depending on the temperature, humidity and how hard the wind is blowing. After the bleed water is all gone, you can get out your steel finishing trowel and put on the final touches. You will notice the steel trowel is not perfectly flat. Thats done so that when you trowel you will be more prone to lift the leading edge slightly avoiding digging into the concrete.

Even by following my outstanding instructions it is doubtful that your surface will look a pro did it. As I said in the beginning, using a trowel isn’t all that easy. However, most of us are good with a broom. If your mother brought you up right, you’ve had lots of practice. Once you are finished with the trowel, simply take a soft broom and gently drag it across the surface. Always pull the broom (never push) and always go in the same direction. Just one pass should do the trick. I personally prefer a broom finish because it makes the surface slightly rougher. This is very helpful for those occasions when your sidewalk is wet. A hard-troweled surface is very slick. Unless your brother-in-law is a really good lawyer, you don’t want someone take a tumble on your property. Besides this way everyone will think you really knew what you doing and you wouldn’t have to tell them about the broom trick.

Don’t stop reading yet or you will miss one very important point. You need to “cure” the concrete. If the concrete isn’t kept moist for a few days it may crack. The problem is that the surface will dry out while the bottom is still wet causing tension, which basically tears the concrete apart. There are several ways to cure concrete. The easiest is simply to spray it very lightly with a hose. You can cover it with a wet cloth such as burlap (do not let the burlap dry out). Or you can use chemical curing agents such as Sakrete Cure `n Seal. The question of how long to do this and how often is a tough one because it depends on temperature, humidity and airflow. The hotter, dryer, and windier it is the more you will have to re-apply water.

Use a Magnesium Float

Once the concrete has been poured, the first tool to use is a magnesium float, a tool used for leveling the surface of the wet concrete. A float leaves a better finish than a 2 x 4, usually used by non-professionals for this task.

Use a Finishing Trowel

To finish the concrete, use a steel finishing trowel to achieve a smooth texture. The tool brings water to the surface of the concrete. Don’t use too much water, but at the time same time, work the tool to create a smooth finish.

Use a Concrete Edger

The next tool to use is a concrete edger. This tool has an L-shaped edge on one side to break the concrete edge away from the form boards. It also has a tapered edge to give the edge of the concrete a professional finish. Use the concrete edger just as the concrete is beginning to stiffen. Lay it against the edge of the form and drag it across the concrete.

Use a Concrete Control Jointer

Concrete has a tendency to crack. To help control where cracking occurs, use a concrete control jointer. Place a 2 x 4 board across the form boards and drag the tool along the straight edge. A rib running down the middle of the tool draws lines in the concrete. If the concrete cracks, it will crack in the joint, rather than in the center of your patio.

Use a Pressure Washer

An old slab of concrete that has a few pits but is still structurally sound can be resurfaced. Resurfacing is an economical way to fix up an existing slab instead of replacing the entire structure. Remember to pressure wash the concrete before resurfacing. Pressure washing gets rid of oil and debris and washes away the top layer of concrete so that the new product will bond to the old surface.

Keep it Simple

Spray the slab with water to keep the material from drying too quickly. Use a mortar mixer chucked into a standard drill to mix concrete resurfacer and water in a five gallon bucket. Wear safety glasses when performing this step. Pour the mixture from the bucket onto the slab and use a concrete squeegee to spread it. The minimum thickness for the resurfacing mixture is about 1/4″.

Use a Concrete Finishing Broom

After the product has been floated across the slab, drag a concrete finishing broom across the surface. The finishing broom gives the concrete texture to make it skid-resistant.