How to Grout Natural Stone Tiles

  • 2-6 hours
  • Beginner
  • 50-150
What You'll Need
Grout bag
Wet cloth

Natural stone tiles can look stunning, both outside and inside the house. They can cause some problems, however, first in making sure they’re laid even and second in grouting. Because the tiles aren’t square the gaps between the stones can be quite large in some areas. Add to that the fact that stone is often very absorbent, it can make the usual form of grouting very difficult.

Step 1 - Preparation

If the stone tile is outside, after the natural stone tiles have been had and had ample time to set-about a week-hose them down. If the tiles are inside a hose won’t be an option so you should wash them down instead.

After that, sweep vigorously with a stiff broom. You want to get as much water as possible out of the area between the natural stone tiles. You don’t want any standing water but you do want the area to be damp, as this will help the grout adhere and sit more easily.

Step 2 - Grout Options

There are 2 ways to apply the grout to natural stone tiles. The first is a grout bag. This is very similar to a pastry bag where you squeeze and direct the grout into the areas between the tiles. It take much longer than normal grouting but produces a better finish where there are more spaces between the tiles.

You can also use the more usual method of grouting. The real problem here is the absorbency of the stone. It can prove to be difficult to remove the grout from the stone without a great deal of work, so you end up spending longer grouting then you might with the grout bag.

Step 3 - Grout Bag

With the natural stone tiles damp, fill the grout bag with grout and pit the tip in the space between a row of tiles. Start to squeeze and continue until the gap is filled with the grout, to the point where it’s just beginning to mound over the stone.

Start to pull the grout bag backward along the line, keeping the fill level between stones the same. Continue until you’ve filled the first line between the natural stone tiles with grout, then carry on until you’ve filled all the gaps to the same level. You’ll find that the process moves more quickly as you continue.

Step 4 - Finishing

Give the grout 30 minutes to harden slightly. Use the trowel to level the grout with the natural stone tiles and also to wipe of excess, cleaning up with a damp cloth. Continue until you’ve done the whole floor, although this can take some time.

After you’ve finished, leave for another few minutes and then sweep the entire floor with your broom. This will ensure that the grout is level and also take away any small pieces of grout that might be on the tiles. The grout will need to set for three days before you walk on the floor.