So blasted confused about hardiebacker and vapor barriers
 

I plan on tiling my bathroom and using hardiebacker to do the job. I also plan on tiling my shower. Its already gutted, the walls I plan on tiling are already gutted so the next step is to get the hardiebacker and install that. The room behind the bathroom is a bedroom.

Now the question is, do I need to install a vapor barrier behind the hardiebacker? Like plastic or something? Or can I just screw the backer right to the studs and then put on a coating of something on the face of the backer to seal the backer before I seal up the seams and screws before I put in the thinset and tile and so on?

Do I need a vapor barrier behind the shower stall it self?
What about out side of the shower on the regular wall that I plan on tiling as well?

It can be done either way, but not both at the same time. You do not want to end up with a moisture sandwich. This includes a vapor barrier that is installed on an outside wall. If your bath or shower is installed on an outside wall and the insulation has a moisture barrier on it, then cut or remove that barrier before installing the hardibacker if you are using a product such as Redgard over ther backer.

If your bath or shower is installed on an outside wall and the insulation has a moisture barrier on it, then cut or remove that barrier before installing a 6 mil plastic over the studs and then the backer without using Redgard.

Plastic is a cheaper way to go, I prefer the Redgard.

The outside wall is formed concrete, no insulation. The front and back are just your typical walls. I think I would just go with the Redgard, it probably cost more, but I would rather stop the moisture BEFORE it gets into the walls :)

I need to do some more work in the shower stall itself, so I am not ready to do that just yet, but I would like to get the wall started. I am tired of looking at the studs and the backside of the drywall

For the bathroom walls outside of the shower Hardi is not required. Moisture Resistant (MR) Drywall is less expensive and OK. No moisture barrier is required.

Inside the shower I would forget about the Hardi which is not waterproof and simply use Denshield which is waterproof. Again, no moisture barrier required. Then you can use Redgard to waterproof the Denshield seams and fastener holes. This doesn't have to be that difficult.:)

If you keep ready stuff on the Internet you will only get even more confused.:yes:

The reason for the HB outside the shower is due to a mold problem outside the shower, the reason I have this mess in the first place (due to a shower curtain getting sucked into the stall and letting the steam and water crall out along the wall. I suspect a plastic shower stopper (not sure what they are called, they fit into the corner and help keep water in) would work. That, and I cannot fit the 4x8 sheets into my truck, have no trailer no and nobody to borrow a trailer from. Delivery would cost too much for the 3 sheets I need. I did wonder about cutting the drywall into sheets that are 2x8' to fit them in my SUV (a 03 durango).

Would cutting the sheets of drywall (or purple board) into 2x8' sheets be okay?

I did a search on home depots website for "Denshield" and it has nothing but an article

I wouldn't be cutting those sheets (long ways) in two-feet wide strips if the wall stud spacing isn't also two feet wide. And it likely isn't!:) Maybe two feet cuts along the four foot dimension would work assuming studs on 16" centers. I suppose you could always lay the sheets on their side to install them. A bunch more seams to deal with but if they are being covered with tile I wouldn't think it would be a major issue.:) Seems like a helluva lot of extra work to me. Why not buy your drywall from a real lumber yard? They would deliver for cheap maybe.:)

Thanks Bud. I too appreciate that information, I hopefully will start replacing our tub with a shower one day soon and will try my best to remember this information.

If you can find 1/2 inch Densshield in your local area I would definately use that for the shower surround walls. I could not find it anywhere near me. Next best thing is Durrock IMO. Then do the Red Guard.