Have poured my ICF basement, and put waterproofing membrane on it, now I want to cover the exposed foam above grade with either Durock, Wonderboard or Hardibacker. It will then be covered in stucco or cultured stone. HD here carries all three in 1/2" thickness. I hate working with the cement board tile backer because of the weight and mess involved, but the Hardibacker says right on it that it is for only interior use.
So what's the big deal? Both products can be used under tile in wet locations, but only the cement board can be used outside? Can anybody offer some insight on this one? I'd really like to use the Hardie product, it seems so much easier to use, but I'm now worried about durability and lifespan if applied to an exterior wall (even if it's covered). The Hardie siding products get wet - why can't this stuff get wet?