I need help with building a steam shower

[Zack1973]

Hello

I am building a steam shower in my basement and would like some advice in regards to what i have done so far and what my next steps are.

So Far i have done the following
installed new framing with a slanted ceiling (to avoid water drips)
installed a vapor barrier around the entire enclosure (ceiling and walls) before the durock
Shower base was pre-slanted with sand mix,then installed liner then another bed of sand mix. correct drain was used.
Installed durock on ceiling/walls and used thinset to tape all the corners and joints.


do i need to apply redgaurd to the durock before i install the tiles on the ceiling and walls. and if i use durock do i just start tiling after it dries. will the thin set hold on the redgaurd. also what kind of grout is recommended for a steam shower?

[Edthedawg]

What'd you use for a vapor barrier? And how is it tied into the liner in the shower base? Is it 6 mil poly sheeting run down continuously into the inside of the liner?

if the vapor barrier and shower liner are tied properly together to constitute waterproofing, you may be all done w/ no further RedGarding. Adding that might make a double waterproof layer, called a "moisture sandwich" which is advisable to avoid.

Also:
- What kind of tape did you use? FibaTape alkali-resistant mesh?
- What kind of thinset was used in the taping? (modified? unmodified?)
- Were the Durock sheet joints gapped when installed?

Again - RedGard doesn't seem to be req'd in this instance. But if you do use it, yes - once it dries, you can apply your modified thinset and tile work right over it. I'll let someone else more knowledgable than me (read: everyone?) pontificate on the merits of specific grouts for steam showers...

Good luck w/ your big project!

[Zack1973]

Edthedawg

thanks for the reply

this is what i did, i got 6 mil plastic (not sure is its called poly sheet) from home depot. the box said vapor barrier. the sheets came all the way down and over lapped the into the inside of the liner. i used some redgaurd to cover the nails i used to secure the plastic into the studs. the durock was gapped and i used fiber tape. the think set was the premixed type so not sure about modified or not. what is the difference ? i

[Edthedawg]

Dang you were doing so well - right til the end. Pre-mixed thinset? You gotta grab the can and relay exactly what kind / brand it is. Pre-mixed tile adhesives / mastics have no business being in a steam shower a lot of the time.

Thinset needs to be a mixed on-the-job material (powder mixed w/ water). They can get pretty exotic, and you may well want one of those fancy types for your shower. But the basic stuff a lot of DIY'rs use is HD's Versabond, assuming you're using HD for your supplies.

VB is a polymer-modified thinset mortar. FlexBond is a heavily modified version - probably not what you want for this application. Again, I'll hold off on specific thinset or grout recommendations since I'm no steam shower expert. But your note of using pre-mixed anything raises more than an eyebrow

[Brian in San Diego]

Zack,

Yeah, the premixed is not a good thing. But you really should get ahold of SR614-07 from the TCNA handbook for ceramic tile installation. The most important vapor barrier is the one you apply to the surface of the CBU. The poly you have is really a moisture barrier meant to protect the studs. It's perfectly O.K. for a shower but a steamer is a whole different animal. In a steamer you don't want the stem to get to the CBU. Some manufacturer's actually recommend both the Poly and the surface applied membrane. Let me see if I can ping one of the pros who has built steamers to help you out.

Brian

[Bill Vincent]

if the vapor barrier and shower liner are tied properly together to constitute waterproofing, you may be all done w/ no further RedGarding. Adding that might make a double waterproof layer, called a "moisture sandwich" which is advisable to avoid.

Wrong, wrong, bigtime wrong. With the exception of Hydroment's Ultraset, ANY of the roll-on or trowel on waterproofings MUST be accompanied by a vapor barrier. They're waterproof, but NOT VAPORPROOF. This would include Redgard. Also, you try doing a steamshower with just a vapor barrier, and you're going to find yourself with moisture problems inside your walls within the first 6 months.

Ed, you need to read the specs before you give advice on this subject.

The one thing I WILL agree on is about the premixed thinset. In ANY shower, but especially a steam shower, premixed thinset (AKA mastic, AKA organic adhesive) should not even be a consideration. That stuff will fail before the first year is up.... if it takes that long. As Ed said, Versabond would be good Flexbond would be better.

[Edthedawg]

I will completely agree I'm no subject matter expert (i think I said that at least a couple times, actually) but I also distinctly recall being told not to do that same thing before - poly on one side and RedGard on the other. But perhaps I'm misremembering that.

So while not looking for any kinda pissing contest, I'm just curious what the proper advice to the OP is - keep the poly and CBU he's got, plus the RedGard? Or is he needing to get rid of the poly vapor barrier behind the CBU?

[cx]

Originally Posted by Bill Vincent

They're waterproof, but NOT VAPORPROOF. This would include Redgard.

The manufacturer of RedGard advertises it to be a vapor barrier, Bill, having a perm rating of less than one.

The only manufacturer of waterproof membranes known to me that actually publishes a method for steam showers using a vapor retarder behind the CBU and their product on the inside is Laticrete. You know of others?

Even the methods published in the TCNA Handbook have "issues" as far as I'm concerned, but they're allegedly being worked on. It's not an easy construction and it has a lot of tricky details to deal with.

Bottom line for me is that a steam shower must have a vapor barrier, and only one, somewhere in the inside wall and preferably immediately behind the tile installation.

The owner of this thread does not have that. He's got an effective moisture barrier behind his CBU, but once his CBU is installed with mechanical fasteners he has no vapor barrier. He could, if all the rest of his construction meets requirements, cover it with Laticrete's 9235 and meet their requirements for their published method. I think. He'd need to contact them to be sure of all the details, but it should be workable.

I still think it's a very bad idea, but ain't nobody at Laticrete listened to my arguments about it to date.

And there's the matter of insulation, which I don't think has been mentioned at all.

My opinion; worth price charged.

[Bill Vincent]

Again, CX, you might check with your rep with respect to its specific use in a steam shower.

Also with respect to Laticrete being the only one, check Mapei's waterproofing, as well. It also needs a vapor barrier. In fact, as I stated above, I've only found one roll/ trowel on where the manufacturer has NOT told me a vapor barrier was not needed, and that was Ultraset.

[Brian in San Diego]

Ed,

Part of what you were talking about is true for regular showers. If you put poly behind the CBU then you don't want RedGard on the surface. When it comes to steam showers each manufacturer may have different ways of specifying how their products should be applied. In a steam shower it is imperative that there be a surface applied membrane. I know I've read what Bill has wrote on the subject in the past and I remember him talking about a moisture barrier behind the CBU.

Brian

[cx]

Originally Posted by Bill Vincent

Again, CX, you might check with your rep with respect to its specific use in a steam shower.

Just going by their published data here, Bill.

[ob1kanobee]

I have seen a handful of steam showers. Never saw one in a personal residence, mostly fancy hotels and luxury high rises.

Everyone that I saw that actually got use had problems either with the tile or just doing what it was supposed to do, make steam. Steam shower out of order was the norm.

I know the two big companies I used to work for used to get pretty crabby when asked to bid a steam shower or have it be included with other work. Seemed like doing one was more of a pain than the liability. Another words, it wasn't worth it.........................

After reading through the information on here though, I realize that there must have been an installation error in these steam showers.

[Bill Vincent]

I've done several of them. Residential and commercial, and I've yet to ever hear of problems with them.

CX-- try asking your rep if he'd be willing to stand behind his product on a warranty. I learned a long time ago not to trust CBP's "published data" (Or anyone else's for that matter). The same data that says it's okay to use their mastic in a shower, so long as you don't use it on the floor. I find that if I ask the area rep to put his money where his label is, they become a little more realistic.

[Zack1973]

thank you all this is great info. after doing some reading i do agree that the premixed thinset is not a good idea, good thing you guys told me before i tiled. in regards to my vapor and water proofing the good thing is the shower is framed into my mechanical room so the other side of the studs will be exposed which will allow me to monitor if moister is escaping or if i am trapping moister in between the vapor barrier and the water proofing on the CBU. i will do some research on the products you mentioned.

someone mentioned insulation. my shower walls are all internal so do i need to worry about insulation?

any recommendations on the type of grout to use ?

[Brian in San Diego]

Yes, Zack, you need to insulate to reduce the risk of condensation.