The rubber tile grout float is a tool that is used to apply tile grout, which is basically colored cement, in the joints between ceramic tile or flat natural stone after it has been set. Tile is usually set with spacers which dictate the size of the grout joint, i.e. 1/8", 3/16", etc. After the tile has cured for at least twenty four hours, it is ready for grout.
For large areas such as floors, a twelve-inch rubber grout float is suitable. It has a rubber base about four inches wide and a curved handle on the top. The grout is mixed with water to the desired consistency and a bucket of clean water and large sponge are used as well. Dip the edge of the rubber float into the grout mixture and scoop out a quantity. Place it on the grout joints between the tiles and holding the float at approximately a forty-five degree angle force the grout into the spaces between the tiles and draw the float toward you. Make sure the grout is being forced down between the tiles as it is important that it completely fill the grout joint, for when it sets it becomes a strong structural part of the tile application. After an area of approximately eight square feet has been grouted, take the sponge from the bucket of clean water and wipe off the excess grout. This should be done several times to get the tile as clean as possible, rinsing and squeezing the sponge regularly. Continue the procedure until the entire tile is grouted.
For smaller or hard-to-get-at areas, a smaller rubber grout float called a margin float is available. This rubber grout float is about six inches long and two inches wide and has a handle extending from the back which makes it easier to get to tighter areas. This float is not recommended for larger areas but is essential for reaching behind faucets on bathroom sink cabinets, etc.
Rubber grout floats are available in different sizes and with varying surface types. Epoxy grout floats, for example, are stiffer than the typical float to allow for the different composition of epoxy grouts. Other, more inexpensive types, are made from dense foam rubber and are meant to be used for smaller projects.
After using the rubber float, clean it up with the sponge and clean water and it will be ready for your next tile project.