If I am not mistaken hardibacker came out just a few years ago and does not have a proven track record. If I am wrong does anyone have long term experience with this product (10 or more years)?
Hardibacker
don't forget it's not the backerboard's job to stop water,but to allow water to pass through it,if it did not the mortar would not dry,....good luck
As for your "water test" of the hardibacker, that is irrelevant. Water and mositure is supposed to pass through it, as opposed to repel it. (That is why thinset mortar adheres to it instead of just slipping off of it; it draws the thinset into it for a better bond.) The TILE and grout are supposed to stop the water before it gets to the backerboard. Moreover, wetting the back of a tile will yield similar results. If the Hardibacker became brittle when wet, then that would be a disadvantage, but, as you might have noticed, it does not, which is another one of its assets.
The backerboard is there to support the tile so that individual tiles set together as one unit once the thinset cures. Hardibacker does not shread like cement board under pressure or jolts, but it adheres to thinset just as well. That is why it is reputed to be better than cement board and often is the preferred backerboard. The primary (and perhaps only) significant advantage to ordinary cement board/wonderboard is that you can score and break it with a utility knife, whereas you should use a circular saw to cut Hardibacker.
I have read the following: "Cement board is not waterproof ... water can wick right through it. And what's on the other side of the cement board? Your house's wood framing.
You'll find manufacturers telling you about their specific product, but they can't say how their product will interact with or protect materials attached to it.
So cement board is essentially not affected by moisture.
Your house's wood framing will be affected by moisture.
Insulation can be affected by moisture."
I AM VERY SENSITIVE TO MOLD, AND I AM CONCERNED THAT IF A WATERPROOF MEMBRANE, SUCH AS REDGARD, IS NOT APPLIED TO THE HARDIBACKER WALLS OF MY SHOWER, (AND ON THE HARDIBACKER WALLS OF MY TUB/SHOWER SURROUND), THAT MY WOOD FRAMING WILL BE (AND MY INSULATION CAN BE) AFFECTED BY MOLD, NOT TO MENTION THAT "UNTREATED MOISTURE DAMAGE CAN ULTIMATELY CAUSE EXPENSIVE STRUCTURAL DAMAGE TO WOOD STUDS AND SUPPORT BEAMS." REGARDING THE HARDIBACKER, THE PERSON TILING MY SHOWER AND TUB/SHOWER SURROUND THINKS IT'S SUFFICIENT TO APPLY REDGARD TO THE SEAMS, PENETRATIONS, AND CORNERS WHERE TWO PLANES MEET. SINCE WE ARE TILING WITH LARGE (AND SOMEWHAT HEAVY) VERTICAL PANELS, SHE IS ALSO OF THE OPINION THAT THE TILE WILL HAVE A STRONGER ADHESION TO THE HARDIBACKER THAN TO A [SOLID] REDGARD MEMBRANE. HELP, I'M VERY CONCERNED AND REALLY NEED SOME GOOD ADVICE JUST AS SOON AS POSSIBLE, AS MY TILE PERSON IS RARING TO MOVE FORWARD. MANY THANKS, JOANNE