Dear James: The grout on the bathroom tiles is crumbling and looks dark even after using bleach. I don’t want to remove the tile and redo it. Can I just replace the grout myself? — Damon W.
Dear Damon: You probably won’t have to remove any tiles in the discolored grout areas. Where the grout is crumbling, water may have gotten behind the tiles and loosened them and damaged the wallboard. Carefully pry on those tiles and remove any that are loose. Examine the wallboard for deterioration.
When there are just a few loose tiles and the wallboard is good, you can stick them to the wall again. Don’t just regrout them and think this will keep them in place. After you have taken care of any unruly tiles, you must remove all of the old grout. This is the most difficult job in the whole project. Unfortunately, you cannot just add more new grout over the old bad spots….