Tile salvage jobs are a popular way of reusing old materials. As green building becomes more prevalent, more old tiles are being salvaged from floors, walls and countertops and are being reinstalled in new applications. Porcelain tiles are extremely dense and durable materials, which makes them easier to salvage than some other tiles. The method for removing the adhesive will depend on what type of adhesive was used.
Use a 6-inch razor blade to scrape away the bulk of the adhesive. This will not remove all the adhesive, but it can get up enough to make the solvent's work easier.
Use a foam paintbrush to spread a paste adhesive remover, found at most hardware stores, onto the old mastic. Allow it to penetrate and soften the mastic. The amount of time will vary based on the remover being used and the age and amount of mastic. Test the adhesive frequently by scraping it with the razor blade to see how easily it is coming up.
Scrape off the softened adhesive with the razor blade after the remover is done penetrating. Use a sponge to clean up the remaining adhesive and prepare the tile for reuse. Allow the tile to dry thoroughly before installation.
Use a 6-inch razor blade to scrape off the bulk of the adhesive from the tile.
Grind off the additional adhesive from the tile with an angle grinder. Continuously move the grinder over the tile. Holding the grinder in one place may etch or damage the tile. Grind the old adhesive down to a smooth finish, or until the tile shows through. The tile should be level and flat for reinstallation.
Use a sponge to wipe down the tile and remove adhesive dust and debris. Allow the tile to dry thoroughly before installation.