Mosaiclegs.. Grouting 101 Byzantine, Bisazza, Sicis

How you grout can make or break your mosaic artwork! Grout not only protects and supports your tile, it frames it and gives it life. Like framing a picture, your choice of color can enhance or compete with the finished piece. The color can emphasize or de-emphasize the design. Lumpy, rough or cracked grout can ruin even the most beautiful mosaic.

Make sure you allocate enough time to complete the grouting process. How it looks when you go to bed that night is how it will look forever! Try not to grout more than you can complete in 2 hrs. For large projects, like walls, where you may use more than 1 bag of grout, mix 2 bags together as color and dye lots may differ between bags.

Humidity can affect how the color dries and how much water is needed to mix the grout. In addition, if you are using different types and different thicknesses of tile in one project you may notice that the grout dries differently around some of them. For instance, a more porous tile may draw more water from the grout and cause it to dry more quickly, causing it to dry lighter as well. These changes are more noticeable in darker shades of grout.

A good estimate is 1 1/2 - 2 cups of dry grout per sq. foot, but it really depends on how far apart and how deep your grout joints are. I usually have leftovers, but prefer that to stopping in the middle of a project to mix more grout.

Do not grout in direct sunlight or use artificial means to speed drying time. This will cause the grout to cure too fast and will cause cracking. To cure more slowly, spray mist with water every hour or so the first day or cover with a paper bag or plastic sheet. Cool, dry places such as a basement, garage or carport are good places to do your grouting.

Grout comes in 2 forms: sanded and un-sanded Un-sanded grout should ONLY be used for grout joints that are 1/8". If the joint is any larger the grout will crack and is also very difficult to smooth out. I almost always use sanded grout. Grout comes in an assortment of colors that are pre-mixed, however, I often mix acrylic paint to white sanded grout to make my own shades. Only lighter colors can be achieved. Too much paint will compromise the strength of the grout. Be sure to mix enough as trying to match the color a second time is usually impossible.

Steps

1. Prepare your project: Use a Dremel drill (available most home improvement stores) with a cone shaped grinding bit to dull all sharp edges before you grout and after the glue is set. Use masking tape to tape over anything that may absorb the grout (wood, seashells, unglazed tiles, etc.) .
2. Prepare your workspace. Lay drop cloth and newspaper to protect the area. Fill one bucket with water and pre-rinse your sponge (some pre-moistened sponges will stain your grout).
3. Mix your grout. Place grout in bowl first and add water a little at a time. It should be wet enough to spread easily, but not runny (thicker than pancake batter but not as thick as peanut butter). Mix well then allow to sit (slake) for 5-10 minutes, then re-stir. I mix grout a little thinner for very porous tiles like Mexican tile (which draws more water from the grout), and thicker for glass-on-glass projects which absorb no water.
4. Spread the grout. With a rubber float or spatula, spread grout over the surface. For uneven or small areas grout can be applied by hand (wear gloves). Watch out for sharp edges! The use of different thicknesses of tile or other elements requires careful placement to accommodate 'beveling' the grout from one piece to the other.
5. Finishing. As soon as the grout is spread 'clean-up' should begin. Remove as much grout from the surface with a damp sponge (wring as much water as possible first) being careful not to pull grout from the joints. After about 10 minutes and/or a grout haze appears (longer for glass-on-glass), buff surface with DRY cloth (no terry-cloth) and then polish each tile again. Q-tips can be used also. Should you notice any pinholes or low spots additional grout can be added with no problem at this time. Grout bags, similar to cake decorating bags, can also be used to apply grout to difficult areas.
6. Sealing. I only use grout sealers for areas that are prone to staining such as counter tops and tables. I prefer a 'penetrating, water-repellant sealer' which does not affect the color or appearance of the grout. I put it in a spray bottle and spray until the grout will not take anymore, then immediately wipe it off tiles with a damp cloth. The use of chemical cleaners will cause the sealer to wear off over time.

If grout haze is difficult to remove, you can use vinegar to remove it! Use sparingly. Apply with a Q-tip when using darker grout colors as the vinegar can 'bleach' the grout. This should be done after you have buffed the surface and before the grout has dried completely, although it will still work several days later to remove haze. Another thing that I recently discovered was Armor all glass cleaner in Can ... these things work really good for getting haze off.