I am installing Racedeck garage floor tiles and have hit a snag. The sections of concrete at the expansion joints are uneven and the flooring will not lay flat. I am debating about using a leveling compound or just grinding off the areas that are raised. Does anyone have any experience with this? I would only need to grind 3 areas totaling 10-15 sq ft. With the leveling compond it sounds like I would need to clean the entire surface that the compound would contact. Could use some advice.