Workers poorly grouted the tiles on the facade. Requires grouting of tile joints. Joints need to go a little deeper and make them even. In what way and with what tools can it be done? It is dangerous to use a grinder or a drill as it can damage the tiles. Suggest a method and the approximate cost of the job. Thank you.
You need a grinder with adjustable speed, put one after the other a few discs on the concrete to the width of the joint. And accurately begin to grind, only this option is suitable for horizontal joints.