Surface Preparation

Surface preparation is the most important aspect of any decorative concrete overlay job. If the surface of the existing concrete is not properly prepared, your concrete overlay could have problems. Here are some of the most important aspects of surface preparation.

First, the surface must be clean and free of oils, paints and sealers. Oils can be removed with a degreaser or detergent. Paints and sealers are a little more difficult to remove. They can be stripped mechanically, with a floor grinder or sander, or they can be stripped with a chemical. A chemical stripper will be sprayed onto the paint or sealer, allowed to sit for 15 or 20 minutes, and then pressure washed off of the surface.

Second, the surface should be pressure washed. A pressure washer of 4000 PSI or greater should be used. This will clean the surface of dirt and dust and it will remove any loose concrete or debris from the surface.

Third, the surface will need to be acid etched with a muriatic acid and water solution. You should use 4 parts water and 1 part muriatic acid. This will etch the concrete and give it "bite" so that the overlay will bond to the surface. Before the muriatic acid solution is allowed to dry, it must be neutralized. Acid can be neutralized with baking soda and water or ammonia and water. If the acid is not properly neutralized, it will leave a film on the surface and the acid etching process will have to be repeated.

Fourth, you will need to repair any cracks that are in the concrete. You will need to make the cracks wider using diamond blades . Then you will use a crack repair epoxy and mesh to fill and bridge the cracks. Some cracks are too big and wide to repair. If you can stick a screw driver down the crack, all the way to the dirt, then the crack is too wide to be repaired and you should just replace that section of concrete. If a section of concrete is replaced, you will need to wait until it is fully cured to apply your decorative concrete overlay.

The fifth and final step will be to patch and level the surface. The patching compound can be used to fill spalled and popped concrete. It can also be used to level concrete that has sunk or fallen.

After these surface preparation steps have been completed, you should be ready to apply your decorative concrete overlay .

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