Do I really need thinset under my backerboard?
Yes absolutely, The manufacturer requires it, and if, for some reason, there’s a problem with the floor afterward, you’ve immediately lost any warranty protection. There’s a big controversy in the industry right now concerning the type of thinset to use. The manufacturers, for the most part, recommend latex modified thinset, whereas the Tile Council of America recommends unmodifed, or dryset thinset. The reason is that the thinset isn’t there to bond the backerboard to the subfloor. If it were, then the modified thinset would make a difference. In reality, it’s actually there to fill the paper thin voids between subfloor and backerboard, thereby eliminating another source of and extending the life of your floor.
The short answer is ABSOLUTELY. The manufacturer requires it, and if, for some reason, there’s a problem with the floor afterward, you’ve immediately lost any kind of warranty protection. Now, there’s a big controversy in the industry right now concerning the TYPE of thinset to use. The manufacturers, for the most part, recommend latex modified thinset, whereas the Tile Council of America (TCA) recommends UNmodifed, or dryset thinset. The reason is that the thinset isn’t there to bond the backerboard to the subfloor. If it were, then the modified thinset would make a difference. In reality, it’s actually there to fill the paper thin voids between subfloor and backerboard, thereby eliminating another source of flex, or movement, and extending the life of your floor.
