Tile Grout Sealing / Caulking
Caulking and Sealing Tile Grout Tips
When installing new ceramic tile, absolutely make sure that the horizontal seam between the bottom row of tile and the tub and/or shower is not grouted! This seam must be caulked with the best quality 100 percent silicone caulk you can buy. These caulks are available in various colors, should you be using a colored grout. Grout will shrink after installation and a very tiny crack will exist, trust me.
The best way to caulk this crack, believe it or not, is to do it in your bathing or birthday suit. Why, might you ask? The reason is simple. The tub should be filled up to the overflow with water when caulking this joint. The added weight of 30 to 50 gallons of water plus your body weight can cause the floor below the tub to deflect. Leave the water in the tub as long as possible to allow the caulk to cure. Don't leave water in the tub like this, however, if you have small children at home! Left unattended, they may think the tub is a swimming pool. Drownings have been known to occur.
AUTHOR UPDATE - April 2015: The following material not in red color was written before I had extensive experience with homeowners who had SEALED their grout and then had the grout get stained by a liquid that had seeped UNDER the sealant. That can happen along the line where the grout touches the tile.
In these cases, the homeowners discovered it's nearly impossible to remove the stain because all cleaners are REPELLED by the sealer.
Now I suggest to people to NOT SEAL grout. If you use Stain Solver, a Certified organic oxygen bleach, it will remove any stain from grout in minutes.
After the grout is dry (three to five days), seal the grout with a silicone grout sealer. These products are available at your tile supplier. Be careful not to get these products on the tub or shower floor, as they are very slippery. The grout needs to be sealed, as it can and will absorb water. Remember, grout is nothing more than fine cement. The sealers also help to keep the tile grout clean. Reseal the grout every six months, after thoroughly cleaning the grout.
Do all of the above, however, clean, clean, clean before caulking or sealing. These caulking and sealing products will not stick to soap scum very well!