My bathroom had 12" square vinyl tile squares which I chipped off. There is some residue of adhesive left on the concrete. Do I need to try to remove it? The floor scraper I have is not working. Will a solvent help? I am laying large ceramic tile with thinset.
I have successfully used orange oil to soften the adhesive holding vinyl squares. I used it undiluted in just enough quantity to soften the adhesive. Then I scraped up the softened adhesive with a floor scraper frequently scraping off the floor scraper with a 3 or 4" putty knife into a trash can.
I then went over it again with more orange oil wiping with paper towels. Finally I used an electric floor cleaner and mopped. The concrete was still glazed and the tile installer used some kind of floor grinder to roughen the floor. I was not present for this; I was out of town. (The serious professional installation specifications for ceramic tile state that fresh concrete is not to be finished with a metal trowel prior to ceramic tile installation.)
Another way to get a porous top, is to etch the concrete. There is an acid etching solution you can spray on and mop off. Its best outdoors since it gives off fumes, but a few fans to exhaust the room and you should be good. Check for this at a hardware store. I have used muriatic acid etch for many things, patio, sidewalk, driveway, even to stabilize hot tub ph.