When you are tiling, you can choose either thinset or tile adhesive (also called mastic) for your glue. There are several things to consider when making the decision between thinset or mastic. Mastic (also called tile adhesive) Premixed, so you don’t have to worry about getting the right consistency Easy to use, which makes it great for beginners Sticky & grabs tile fast, which works great for vertical installations Use in fairly dry area (like backsplash) that doesn’t not get submerged in water  Not recommended for large format tile (over 15 inches on any side) Thinset Mortar Stronger than mastic (all flooring should use mortar)  Can be used in high moisture areas (showers, bathtub, bathroom flooring)  Must be mixed and needs to be the right consistency to work correctly (consistency is like creamy peanut butter)  Must use all mixed mortar immediately Takes longer to dry than mastic, so easier to adjust crooked tiles, but risk of tile sagging when installed vertically  There are several different types of thinset mortar, which depend on your tile size and tile materials so be sure to read up and choose the right one for your job.