Do you need an additive?
You might use additives in your vehicle’s fuel tank, but can they do anything for your grout? Well, they can make the grout more flexible and also stronger after it has cured. They can help the bonding and improve color. If you decide to use additives, add them when you mix the grout [source: Online Tips.org].
Epoxy Tile Grouting
All grouts are not created equal. You may have used grouting to caulk a window. That kind of grout is composed of elastomer and is cement-based. It's not what you want for a tile project. What you need is an epoxy grout, which comes in unsanded and sanded types. It's resistant to most stains and chemicals [source: Kolle, Online Tips.org].
Epoxy grouts include a hardener and an epoxy resin. This gives the grouting a strong bond, chemical resistance and better resistance to items that may be dropped on the floor. Because it's expensive, it's generally reserved for industrial and commercial use. It won't work well if you're using tiles that are more than half an inch (1 centimeter) thick, or if your grout joints are a quarter -inch (centimeter) or smaller. However, if you're placing tile in an environment where it will be exposed to grease or acids, or in a heavily trafficked area, epoxy grout is your best choice [source: Online Tips.org].
Applying epoxy used to be tricky, because it was hard to apply and had to be used within 45 minutes of being mixed. Newer epoxies have detergents added to the hardeners. This means that they're easier to work with and can be quickly cleaned up with water. Epoxy tile grout can cost four times more than cement-based grout. However, those less expensive grout mixes last about a year; two-part liquid epoxy lasts forever in sealed containers if not exposed to extreme temperatures [source: Kolle].
Some epoxy grouts are modified with Portland cement. This gives the epoxy many of the qualities that make cement grouting easier to work. Consider your needs and the strength of bond you will need for your project [source: The Tile Doctor].
All's well and good, you may be thinking, but are epoxy groutings my only option? By no means -- read on to the next section.