Hardibacker on concrete

[600rob]

I contacted the manufacturer about using hardibacker directly on top of a concrete floor to serve as a flat base before tiling.
They advised me that they dont recommend using it on concrete but didn't say why.

Does anyone know why this might be?

 

[23vc]

Probably because it wouldn’t be solid bedded and you’d get weak spots, why would you want to attempt it? Just Self level it.