When you contemplate tiling, you're often confronted with a whole array of adhesives. It's hard to know which kind of tile mortar to choose, but we can break it down into 4 main categories.
1.) Thin-Set Tile Mortar
Use thin-set tile mortar for floors and outdoor tiles. Thin-set tile mortar is the stuff you will probably become most familiar with in residential tiling applications.
Thin-set tile mortar provides a very strong bond, and it's fairly resistent to moisture though not impervious. Since thin-set tile mortar has a tendency to crack (beware if using on a floor that flexes a lot), you will most certainly be mixing the dry powdered thin-set tile mortar with a special latex additive. There are two main kinds of thin-set tile mortar:
- Dry, Powdered Tile Mortar. Extremely difficult to mix properly if you don't have the proper equipment. Strongly recommend against getting dry thin-set mortar unless you have huge areas to cover (the dry stuff is far cheaper than the premixed mortar). Also, you will need to add the latex additive to the dry mix.
- Premixed Thinset Tile Mortar. This comes in big tubs, premixed and with the latex additive already in it. Even though it's heavy and more expensive than the dry mortar, I cannot overemphasize how much time and misery the premixed mortar will save you.
Why use thin-set mortar? The main reason is because it's relatively inexpensive and because it stays wet and mushy for awhile: tiles do not stick to it immediately. This is a desirable property. You want tiles that you can jiggle around to get in the right position. Thin-set tile mortar also allows for you to level otherwise unlevel surfaces--to some degree. You can't level wildly out-of-level surfaces, but you can bridge gaps and compensate for slight level changes. Thin-set tile mortar has a very smooth, slippery consistency, similar to mud.
2.) Organic Mastic
For lack of a better term, we call this petroleum or latex-based product organic mastic. Use for wall tiles
or other vertical surfaces where you want tiles to stick immediately, and to stay stuck. Also unlike thin-set tile mortar, the organic mastic doesn't let you level the substrate (or, underlying surface).
3.) Brick Mortar
As the name implies, brick mortar is a coarser type of mortar than thin-set. It has larger gauge sand and even small pebbles, ideal for mortaring brick walls and walkways.
4.) Epoxy Thin Set Mortar
A resin-based mortar that comes in three separate components: resin, hardener, and powder. It sets very quickly, is extremely strong, and unlike thin-set tile mortar, will allow you to get to the grouting within just a couple of hours (thin-set must set for days). It's very impervious to water, so it doesn't need any kind of special additives. Downsides include a powerful smell and its great expense. Also, the fact that it sets quickly can be a deficit because it does not allow for you to make changes.