Adhesive for concrete board and tile

[hotinhawaii]

I've done it both ways, liquid nails and thinset. I have never had a problem either way. I suspect that thinset fills any gaps between the subfloor and backer board better, but once it is screwed down and the tile is installed, will tiny gaps make a difference anyway? The liquid nails approach is faster and easier in my opinion. I did encounter a problem once when I used a non-modified thinset (without any latex additive). The backer board sucked the moisture out of the thinset before it set up and months later the tiles all popped off. If using thinset, either use the modified or add the latex additive. Another lesson learned.