dry pack shower floor w/ backer board walls

[jonholzer]

I plan on doing a mudset shower floor and plan to use 1/2" backerboards to do the walls. Got most of the materials then had several emergencies to deal with during which time the company I was dealing with closed and left town.

The information I got from them seems to be similar to info I got from John B.
but several questions Ineed answered have come up, like cure time for the mortar (slope layer) before installing the liner. Also gap between the liner and the backer boards on the wall. John also says to add lime to the top layer and I assume to pound the tile into the top layer, skipping the thinset.
I had planned Custom Products redgard then thinset then the tile.

The previous owher had a shower in the same location- installed in 1994- and the ceiling is drywall (don't know if greenboard) and it is fine, but I would like to add an additional coat of redgard to give a better vapor barrier. The ceiling is dry in the crawl space above the shower and the paint is intact with no pealing or bubbles. Do I need to redgard it?

any thoughts are welcome

Jon Holzer

[Davestone]

24 hours for cure time.I think you're making this hard on yourself, why bot just float your flor and use thinset next day?But if you wanna mudset there's a couple ways of doin it, you can use the lime..or portland,soak ceramic, but this mudset way isn't good for porcelains, unless you're real careful.You can also skim a thin coat of wet slurry thinset over the plastic mudbed and beat them in a little.I don't know what you mean by gap between pan and cbu.I wouldn't worry about redgard on the ceiling.Looks like you have a duplicate thread, i'll delete the other.

[jonholzer]

Davestone

I'm not sure how to followup on your post, thanks for deleting the dup.

I assume a float would be a wetter mix? gap- I've read else where to allow a ~1/4 in gap between the liner and the bottom of the backer board, I think to keep the weight of the backer bd off the liner.

Jon