How to Use a Float for Grouting

Anyone who has successfully laid a tile floor or wall knows the satisfaction of a neat tile job. To take a stack of fired ceramic sheets and stick them in place with wet mortar is something approaching magic.

Once you master the skill of tiling, you'll want to tile every part of your house. The final tiling step that brings it all together is grouting. Grouting is done with one simple tool: a grout float.

A grout float is a simple, inexpensive tool that will last for years. Knowing how to effectively use a rubber float with grout means the difference between a clean tile job that lasts for decades, and a tile job that cracks and eventually falls apart.

What a Grout Float Is

Grouting is an important part of any tile installation. Grout fills the spaces between tiles, called grout joints, to create a continuous surface.

At first glance, the most logical way to add grout would be to squirt it into the seams, as you already do when caulking other areas of your house.

Instead, grout is applied with a broadcasting approach rather than a laser-targeted approach. Large mounds of wet grout are scooped into the entire tire surface—seams and tile surfaces alike. Then, the grout is wiped across the tile. Grout embeds in the tile seams but not on the tile surface. Excess is picked up by the grout float and redeposited elsewhere on the tile.

The only way to apply grout properly is by using a rubber grout float, which consists of a rectangular non-stick gum rubber or soft nylon pad. This pad is firm but flexible and which prevents the absorption of materials.

The user holds the float with a C-shaped handle. The process of grouting with a float includes filling the joints with freshly mixed grout and scraping the tiles clean of excess grout. It is a simple yet elegant technique that has served tile setters for centuries and it's still used today.

How to Use a Grout Float

To use a grout float, you'll need a grout float, mixed grout, a bucket, and a tile sponge.

1. Add Grout to Tile Face

   Add some grout to the face of one of the tiles. Start with a small amount: roughly a ball that's about 3 to 4 inches diameter.

2. Sweep Float at 45-Degree Angle

   Holding the grout float at about 45 degrees, with one edge on the top of the tile face, sweep the grout across the tiles. Work in sections that are about 3-foot by 3-foot.

   Be sure to sweep across the tile diagonally; that is, the float passes over the tile seams at a 45-degree angle to them. Otherwise, the edge of the float will pull grout out of the seams.

3. Scrape Grout at Nearly 90-Degree Angle

   With the grout float held at nearly a 90-degree angle to the tile, scrape across the tile to remove as much grout as possible. You may need to make several passes. As before, sweep diagonal to the tile seams.

   Redeposit the grout back in the bucket, to be used in the next section of tile.

4. Wipe Down Tile

   With as much grout removed by the float as possible, switch to the tile sponge. Soak the sponge in clean water, wring it out, then pass it lightly across the face of the tile. Use a couple of buckets of clean water in rotation to keep your sponge clean. Be careful not to pull out grout from the seams.

Floor vs. Wall Grout Floats

Rubber grout floats come in two types: wall floats and floor floats. The chief difference is that wall floats have softer rubber pads than floor floats, which can be quite stiff.

Wall floats are generally easier to use and are better for reaching into corners, so they are a better all-around choice for beginner tilers. The tools you find at the store may not indicate whether they should be used for walls or for floors. Some may be called a universal float.

Compare the softness of the pads to identify the type. Sometimes it is worth spending a little extra for a quality float, especially if you have a large tile job or if you plan to tile other rooms.

Grout Float Troubleshooting

Grout keeps getting pulled out by the grout float

As a general rule, move the grout float diagonally over the grout joints. This prevents the edge of the float from sinking into the joints and pulling out the grout.

Sometimes you have to work parallel to joints, such as when grouting along the edge of a wall or floor, but do so with care. Otherwise, sweep the float diagonally. 

Grout smears across the tile but doesn't embed in the seams

Fill the grout joints by spreading the grout across the tiles while holding the float at an angle of about 45 degrees to the tile surface. This is the standard for floor tile. A higher angle might pull out too much grout from the seams, while a lower angle will smear the grout across the tiles.

When tiling walls, you may find a lower angle (about 30 degrees) more effective for filling the joints.

You can also reduce the angle if you reach a problem section that doesn't seem to be taking the grout very well.

Grout remains on the tile after using the float

When all grout joints in a work area have been filled, make a second pass with the float to remove excess grout from the tile faces. This time, hold the float at a steep angle of about 80 to 85 degrees—almost straight up and down. When working carefully, a steep angle can clean the tiles without pulling grout from the joints. 

Haze remains on the tile even after many passes with the grout float

Leave the grout haze for later. A rubber grout float does a nice job of scraping the excess grout from the tile faces, but it cannot make the tiles perfectly clean. It usually leaves a film of chalky grout residue that you clean up with a grout sponge after the grout has set.

Your cleaning pass with the float should remove all blobs and chunks of grout, but you can leave the haze for later. Clean off the grout haze with a special solution called haze cleaner applied with a clean sponge.