Grouting can be a rewarding task. It's the last step in a tile job, so you know you're almost done. And filling the joints with grout brings out the beauty of the tile. But if you've ever had grout turn rock hard before getting it off the tile, you know grouting can also be a nightmare. So to help you avoid problems and get the best results with the least effort, we've assembled these grouting tips.
Let the grout slake
It's tempting to skip this step, but it's important to let the grout set for 10 minutes after mixing. This step, called slaking, allows the water to completely moisten the dry ingredients. Remix the grout after the slaking period and adjust the mixture by adding a little more powder or water until you reach the viscosity of mayonnaise. Be careful, though—it doesn't take much of either to radically change the consistency.
Don't spread too much grout at once
Temperature and humidity affect how quickly grout starts to harden after you spread it on the wall. And once it does start to harden, you'll really have to hustle to get it cleaned off the tile and get the joints shaped before the grout turns rock hard. Avoid this problem by grouting small areas at a time. Start by spreading grout onto a 3 x 3-ft. area. Finish grouting, shaping the joints and cleaning each section before proceeding.
Force grout into the joints
For a long-lasting grout job, make sure all the joints are completely filled with grout. To accomplish this, make several passes over the same area from different directions with the grout float. Hold the float with its face at an angle of about 45 degrees to the tile to force the grout into the joint. When the joints are filled, remove excess grout from the face of the tiles by holding the float at almost 90 degrees to the tile and scraping it off.
Tool the joints
Shape and compact the grout by dragging a tool across every joint. The tool can be anything from the rounded corner of the grout float to the rounded end of a toothbrush handle. Whatever is handy and has about the right radius to create a slightly concave joint will work. Don't use metal tools. They can damage the tile or leave marks.
Use a clean, damp sponge to remove grout
Start with a clean bucket of water. Wet your grouting sponge and wring it out until it's just damp. Then, starting along one side of the grouted area, position the sponge so that the corner of one long side of the sponge is in contact with the wall and drag the sponge in a continuous stroke up the wall. Now rotate the sponge to expose a clean corner and repeat the process alongside the first stroke. When you've used all four corners of the sponge, rinse it in clean water, wring it out, and continue the process until you've cleaned the entire area once. Clean the tiles two or three more times using the same process until they're free of grout residue. A thin film of grout may appear when the water evaporates. Buff this off with a soft cloth.
Don't scrub the grout or use too much water
Let the grout harden slightly before you clean off the excess. Test the grout by pressing on it with your finger. When it's hard enough to resist denting, you can start cleaning the excess grout from the face of the tile and shaping the joints. Two common mistakes at this point are using too much water, and scrubbing the tile like you're washing a wall. Too much water will weaken the tile and cause the grout color to be uneven when it dries. And scrubbing doesn't remove grout efficiently; it just moves it around.
Remove grout from corners before caulking
Because it's flexible and can handle slight movement, caulk is used at corners instead of grout. For a good tile installation, apply a neat bead of matching caulk at vulnerable areas like along the tub or countertop and at inside corners. But to achieve a good-quality caulk joint, you'll first have to remove the grout from these areas. Most home centers and tile shops will have caulk to match the color of your grout.
Seal porous tile before grouting
If you don't seal porous tile and stone, grout will stick like glue and be nearly impossible to clean off. There are two different products that can make it easier to clean grout from porous stone and tile. If you're installing a matte finish tile or other tile with a rough or porous surface but don't want the sheen that a sealer would leave, apply a liquid grout release product. Grout release forms a thin film that prevents grout from sticking but washes off as you clean off the grout.
Use a sealer rather than grout release if you want to enhance the color of stone or leave a “wet” looking finish. You may have to apply another coat of sealer after grouting for maximum protection and to enhance the color of the stone.