The grout in between your slate tiles may need to be regrouted after a certain period of time, especially if the floor is a high traffic area. Some parts of the grout may have started showing signs of crumbling, cracking or corrosion. Consequently, it is a good idea to know how to regrout the tiles.
Step 1 - Removing the Old Grout
First you have to remove the old grout. You will need to attach a grout extraction bit to your drill. Place the tip onto the grouted line and turn it on to dig out the grout.
Step 2 - Cleaning Up
Once you are done, sweep the floor to remove the pulverized grout, the dust and other residue. Then, vacuum the area to get rid of the dust particles that remain.
Step 3 - Regrouting
Now you can start applying the new grout. It is best to use unsanded grout for slate floors. Scoop a small amount of grout on a grout squeegee. Then, start to apply the grout into the lines and joints in between the tiles by pressing it downwards. Scrape away any excess grout. Use a dampened sponge to wipe the area, but be careful not to wet the grout you have just applied. Allow the grout to dry thoroughly before treading on the floor so that it can set well.