DEAR TIM: Grouting tile is a job I need to tackle before my relatives come over for a holiday party. I don't know how to grout tile, but feel it is easy. What type of tile grout should I use for my ceramic floor tile? Is mixing grout difficult? How much grout should be mixed at one time? Can you share your top grouting tips? Amy H. Oakdale, MN
DEAR AMY: There is not a doubt in my mind that you will succeed grouting your ceramic floor tile. You have asked many of the right questions concerning grouting tile. Although the process of grouting tile is not like laying heavy concrete blocks, I can think of easier jobs to do. If you protect your knees, back and skin on your hands, you should survive the job with very few aches and pains.
Grout that is used for ceramic tile is available in many different forms, but the two most common are wall grout and sanded floor grout. Wall grout is usually colored Portland cement. It is a fine powder that sometimes has dried acrylic modifiers that help it to stick to ceramic tile. Wall grout should be used on ceramic tile joints that are one-eighth inch or less in width.
Ceramic floor tile is often installed with grout joints much larger than one-eighth inch. It is not uncommon to see grout joints as wide as three-eighths inch. Wall grout can shrink when used to fill joints this wide, so sanded grout is used. Sanded grout is a blend of wall grout and fine particles of silica sand. The silica sand makes the grout very durable to wear and tear and takes up room within the grout so as to prevent unsightly shrinkage cracks as the grout dries and cures.
I find it fairly easy to mix either wall or sanded grouts. The trick is to only mix about as much as you can fit into a half-gallon milk container, maybe less. You may discover that when grouting a floor, you can mix two or three times this amount, but for the first batch, mix little until you learn how to grout. If you are doing this job solo, then you need to realize that you will spend time removing excess grout from the floor tile and striking the joints with a grout sponge. As you do this tedious work, the mixed grout can harden in the bucket causing you to waste any grout not placed in a grout joint.
Mixing grout to the right consistency is very important. You want the grout to be workable so it can be spread with a rubber float, but it should not be so wet that it resembles moist, runny cake icing. I feel the best consistency for either sanded floor or wall grout is when the grout is stiff enough that it can be formed almost into a ball and hold its shape.
When the grout is this stiff, the grout paste fills the joints to the top without sagging or creating small depressions when wiped with the grout sponge. Grout joints that are fully filled, look better, clean easier and they protect the fragile edges of the ceramic tile.
Since you are a beginner, the most important tip I can give is for you to practice grouting on a piece of tile-backer board in your garage. Install some scraps of the floor tile or a cheap tile that is similar to the one on your floor. Attach this tile to the piece of backer board that is just laying on the garage floor. The next day, mix some grout and apply it. Wait a few minutes and remove the excess grout and grout film with a grout sponge. Get a feel for the process before experimenting on your real floor.
Always pull the rubber grout float across the grout lines at a 45-degree angle. This prevents the edge of the float from dropping down into a grout joint and scooping out grout from the joint. Remove as much excess grout from the tile surfaces as possible with the rubber grout float. When removing the grout film from the tile, use a grout sponge that has rounded corners, and be sure to squeeze out all excess water from the sponge before the sponge contacts the grout. Change the rinse water frequently.
The biggest cause for grout failure is water. Either too much is used to mix the grout or too much is used when removing the grout film from the surface of the tile. Excess water dilutes the amount of Portland cement in the grout. When this happens, the grout can turn to powder or simply crumble in a short amount of time.
You only want to grout as much tile as you can reach across. Kneeling on top of freshly grouted tile joints is not a great idea as you try to finish the floor. Think about where to start grouting the tile and how you will exit the room once you are finished.
Buy plenty of grout before you start the job. Be sure it is fresh, and absolutely make sure the grout is from the same batch or dye lot. To ensure perfect results, it is often a great idea to blend different bags of the dried grout together to make sure the finished color of the grout is uniform.