Do You Have To Acid Wash Concrete Before Sealing

To clean concrete before sealing the surface needs to be free of any contaminants and be porous to allow the sealer to key into the concrete.

Do you have to acid wash concrete before sealing.

Carpet glue tile mastics water and urine stains chalk marks caulk grease stains paint drips and rust spots are just a few of the contaminants you may encounter once you remove an existing floor covering. Improper surface preparation can result in poor bond and lack of coating adhesion. The surface of the concrete should have been neutralized after acid staining with a solution of 1 2 pound baking soda mixed with 5 gallons of water. Concrete sealers enhance the protection strength and longevity of your concrete helping them reach their full potential without problems and costly repairs.

Acid etching removes laitance but cannot remove curing compounds or many of the contaminants found in industrial settings such as oily deposits and water insoluble materials any of which can interfere with the adhesion of a coating. So long as you properly neutralize and rinse the concrete well a couple of times it should be fine. If you do not properly neutralize the stain then the sealer will lose it s bond which will then have to be stripped and re applied. Acid washing is dangerous for people plants and metal objects especially indoors where fumes can concentrate.

Take some water and mop the surface to remove any dirt dust or small debris. A concrete patio may have a smooth shiny surface that makes it slick when wet or that prevents paint or sealer from adhering. Driveways pavement concrete that has been weathered for years may already have the shiny top layer removed naturally and all it needs is a good clean with a water jet to prepare it. Once you clean all these agents off the top of concrete you can begin preparing the surface.

You can also use acid in weaker concentrations to remove white mineral deposits efflorescence and heavy grime. The reason for washing the residue is to neutralize the acid. The concrete surface preparation is very important. If you choose to skip the etching step before applying the paint the paint may bubble up peel or flake off the concrete.

Do choose the right cleaning product for the job see questions to ask when choosing a concrete cleaner or degreaser. You will need to use an acid based solution like muriatic acid to rough up the surface if the top of the concrete is still smooth. Acid washing also known as acid etching prepares a concrete surface to accept a sealer. In addition to creating a rough surface for the paint to adhere to acid etching removes salts from the surface and neutralizes the ph level of the concrete factors that prevent the paint from sticking to the concrete.

However if you have not yet treated your concrete with a concrete sealer it is important to properly prepare the concrete slabs before applying a sealer. Acid washing etches the upper layer of cement exposing more of the sand in the concrete mixture and making the surface feel rougher.