Which is better adhesive or mourter for applying ceramic tile on cement board floor?
Muself, I use mortar for the application. But you will probably get answers each way.
Specific brand and line, TEC Sturdiflex, the best I've used. It is a latex modified thinset mortar. Really easy to work with, and in 10-12 hours is bonded. With some other brands I have seen them still soft after that amount even in dry warm weather. TEC also has a full line of other mortars. In fact for setting the board, you should regular thinset mortar, not latex modified. TEC's line is SturdiSet, as opposed to SturdiFlex, for backerboard. But they are other brands that do well, too. As a contractor, you find something that you trust and works well, you tend to rely on it. With that in mind, it is the best mortar I used, and would use it in my own house. I wouldn't use a mastic or premix, in the average situation, for a floor. There's my unpaid endorsement for the year. haha.
The first and most common is Polymer Modified thinset. It's the least expensive, and the most common for a floor. MAKE SURE YOU GET POLYMER MODIFIED. It will say on the bag. The next is a premixed tile mastic. This is usually used for walls since it has more initial grab and helps keep the tiles from vertically sliding. There is nothing wrong with using premixed mastic as long as the tile is indoors. It will cost more however, and will also take longer to dry. If your doing a small area it might be easier since you don't have to mix it.
Use a thin set that has some flex to it. It is best for most applicatons even on a concrete slab. I have found that with ultra flex brand I have never had a problem like with others. Your floor can move slightly and the other stuff will either cause your tile to crack or pop loose. Make sure you mud the joints and use mesh tape. If you are doing this in a manufactured home all the precautions in the world sometimes don't help.
I would use canned adhesive that you spread with a trowel. It is more uniform. Does not break down like morter will, since morter has sand products in it. Besides, ceramic tile usually has spacing that will be filled in by grout, but some actually butts up together, and some comes already attached to a mesh backing. I believe adhesives that are on the market are much better than morter. In addition, adhesives have better holding power, even on cement board flooring, as long as when you trowel it in, you assure you apply pressure on the trowel to force the adhesive into the cement board matrix.
