[kevino2640]

Jaz man, I’m not trying get personal and it seems you are, and I’m certainly not trying to hide behind a username. I was just trying to help a beginner who seemed confused since he’s been told 2 different things.

My code doesn’t require a vapor barrier and my point is you don’t need one with Hardibacker by the nature of it’s composition. Your plain wrong on them requiring a barrier - their directions say “check your local code” and doesn’t say you absolutely need it. Why would they leave that out of their installation videos if you really needed it?

They specifically say not to use a Redguard or similar waterproofing on the face as it will not allow thinset to bond as well. I’ve had a number of pro tilers tell me they never install a vapor barrier behind or waterproof the front of Hardi-backer. It's already waterproof. To say you must have a vapor barrier with Hardi is just not true. Now again, I'm talking about tub surrounds, not pans.

To say an installation may fail w/no barrier is nuts. We've all seen 30-40 year old homes with tile that was just stuck to regular old drywall with mastic
in a tub surround and no leaks or mold. Of course, I don’t condone this, but my point is it’s still on the walls and in decent shape.

back in the good old days homes were made with plaster on the inside no mold would grow no matter what then they came out with drywall a substance mold loves to grow on stachibautrous a poisonous type of mold loves drywall will grow when drywall gets wet. So mold and moisture are much more of a beg deal now.
every competent tile man will tell you that a vapor barrier is needed between the studs and hardie backer

if you want to know if hardiebacker is water proof just take a bucket cut a hole in the bottom glue the bucket to the hardiebacker and poor 8 ounces of water in the bucket. if the water goes through the hardie backer in less than 7 days obviously it is not water proof.