This isn’t an uncommon issue. Existing concrete layers often have paint drips, dirt, liquid stains, carpet glue, or other markings. These defects can be as old as the house. While building or painting, builders tend not to clean up these types of spills. They expect any spills to be covered up at a later time by carpets, wooden boards, tiles, or other flooring materials. The spills aren’t an issue until the flooring materials are removed and the concrete floor is once again exposed. This was exactly what had happened at the home in Richardson.
In all concrete refinishing situations, we clean the existing concrete surfaces thoroughly to remove dirt and stains, but other defects may not be removed. When we apply a color stain to the concrete, any remaining defects can cause unwanted colorations.