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. And the crowning touch of all tile installations is the application of grout. Knowing how to use a rubber float with the grout means the difference between a clean tile job that lasts for years, even decades, and a tile job that cracks and eventually falls apart.
Why Use a Rubber Grout Float?
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. Not so. The way grout is applied is more of the shotgun approach rather than the 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 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 that 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.
Choose the Right Float: Wall or Floor
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.
Move the Float Diagonally
As a general rule, almost always 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.
Use a Lower Angle for Filling
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.
Use a Steeper Angle for Cleaning
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.
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.