Surface Preparation Frequently Asked Questions
What About Acid Etching for Surface Preparation?
Were you interested in concrete etching or engraving information?
For Concrete polymer-modified overlays:
Contractors and manufacturers are split between roughening the concrete by mechanical profiling or acid etching. Large or difficult surfaces will usually be mechanically profiled.
Acid etching can provide adequate surface preparation for horizontal installations of coatings, and toppings in areas that are well ventilated and require a spark and/or dust free environment. But they will not remove petroleum-based products or animal vegetable oils from the concrete. Acid etching is meant to create a surface profile not clean the concrete. To clean or degrease concrete use specialtly cleaning products. Newlook International has products available to clean and profile concrete.
After acid etching is done the surface must be neutralized. Bonding problems can occur if acidic residue remains on the concrete.
ASTM D 4262-83 is the test method for pH for chemically cleaned or etched concrete surfaces.
You can review and buy the ASTM documents. Click here.
For Floor Coatings in Industrial or Commercial Applications:
Mechanical profiling is the method of choice. Thomas Kline of Structural Preservation and William Perenchio of Wiss, Janney, Elstner Associates, Inc. note that acid etching should only be done when no alternative means of preparation is possible.
Again, the safest measure is to follow the floor coating manufacturers installation instructions.
What About Installing a Non-Breathable Coating?
If shotblasting or scarifying is used to remove the top of the concrete surface to profile the concrete, this opens the pores of the concrete. Open pores means air can now more readily escape from the concrete.
If a non-breathable coating is applied, the escaping air can create air bubbles and craters in the cured coating. In this condition- multiple primer coats should be applied prior to installing the coating. Again, check with the coating manufacturer.
It may also help to apply the coating at night: there is less chance of water vapor to be drawn out into the air when the air and concrete temperatures are similar.
What Happens if Surface Prep Contractor and Coating Installer are Different Companies?
Communication must be very clear in these conditions. A natural conflict can occur if problems develop with coatings: each party can find something wrong with the other ones work.
The surface preparation contractor should present a work plan that is checked for compatibility with both the coatings to be used, and the job schedule.