Either 6 mil poly or 15 pound tar paper behind the backerboard, or a roll on waterproofing over the face of it. The waterproofing over the face of it is actually better, so you're okay. Are you using a tile base, or some kind of preformed base (fiberglass, plastic, enameled cast iron, etc)?

OK, so do we use Laticrete Hydro Ban or Hydro Barrier...they are 2 different products? Will my DH put Hydro Ban/Barrier on first before he tapes and seals the Hardi seams? ...or after seams?

DH actually built the pan for the shower (concrete)....he was insisting to do it that way. Although a DIYer he is a perfectionist....but again getting advice from an "old schooler" ...its already built...so I am praying that it is correct!

Can we put the Hydro product on the concrete shower pan also?

This is all scaring me.

Hydroban. As for doing the seams, there's no need to use mesh tape, because with the

Hydroban, you're going to use a 6" wide fiberglass cloth to bridge the joints and keep them waterproof as well. Not sure how well you can see it in this pic-- it's pretty continuous-- but if you look closely, you can see the bands of cloth under the Hydroban:

Ok, great!

So now DH needs to use Hydroban in conjunction with fiberglass cloth for the joints (I can see them faintly in the photo you attached) once this dries we use thinset to set the tile.

I know need to convince DH that he needs to do this!!

Copying this from a different thread, hopefully this info will do the job in convincing him.

Ok so here is a lesson on concrete board. It is the correct product to use for tile but it is concrete. Concrete is like a sponge and allows water transfer. Concrete board does not mold and wont break down when it contacts water, but it needs waterproofing above it before tile is layed, either kerdi membrane or hydroban/redguard/aquadefense coating. Any framing behind the concrete board witout waterproofing may get wet with each shower, and you are looking at mold and rot behind.

thank you for posting that! I am going to show him this when I get home.

Bill- Thanks for the photo and explanationl...I really appreciate it!

Vithdude- thanks for the fact posting.

I just hope DH don't start to worry about the other tub/bath combo. What's done is done and it wont be used regularly so I'll just hope for the best on that one.

Appreciate the help!!

One more thing. just ready that before putting anything on the concrete we need to wait 28 days for it to totally cure...is this correct?

DH may have used deck mud for pan and I know he has a liner under whatever the material is...... so is membrane necessary on the shower floor?

OK thanks, pan is concrete and does have a liner...so we will only need barrier on the walls. Told DH about this and he wants to remove the hardi and put 6mil poly behind.

Glad we don't need to put (hydroban, redguard, aquadefense) on pan because we would need to wait a month (28 days) to do it!!!

thanks again, great info!

Good advice. ^^^

Is the liner on the flat floor? If it is then water will pool there and not drain. The liner needs to be on a sloped floor and then more mud on top of that. Isn't that right Bill V.?

yes, liner with concrete over, sloped (toward middle drain) so water will not pool. But, thanks for sharing this bit of info.

Do you mean a slope, then the liner, then another slope, then the tile? that is what I believe needs to be done. Many posters here have had the liner on a flat floor then a sloped mud bed on top of that. Trouble would start almost immediately after use.

DH just told me he did layer of concrete then liner then slope. I am really hoping that trouble will not start....

Is it concrete or deck mud? It needs to be deck mud. And you seem to be missing the point about the first layer of deck mud (not concrete) needing to be sloped, as well as the top layer. SLOPED layer of DECK MUD, followed by liner, followed by SLOPED layer of DECK MUD.

I am actually really NOT missing the point, I am telling you what was DONE and what MATERIALS he used. ....and he did use CONCRETE.... and he did a layer of concrete then the liner then the CONCRETE slope (NOT deck mud). DH was learning from old school guy and this is the way he showed him how to do it.

Anyway to correct this now that it is done? besides the obvious of taking it all out and starting over....

Although it SHOULD be deck mud, it can be anything, so long as the end result is that both the membrane AND the final slope are pitched a 1/4" per running foot to the drain.

Yes, I do know that the final slope are pitched a 1/4" per running foot to the drain.

Thanks Bill!

To clarify what enduring wrote, he should have put in a "preslope", a sloped layer of deck mud. Then the liner goes over that. This way the liner itself is sloped. Then another layer of deck mud, about 1-1/4" thick, goes on top of the liner. He'll tile on top of the second layer of mud.

And "deck mud" versus "concrete"? He might be using the right thing and calling it the wrong thing. But he should be using "deck mud", which is a mix of about 5 parts sand to one part portland cement. Mix it dry. Then add just enough water so it's like moist beach sand. When it';s dumped out of a bucket, it doesn't flow like typical concrete. You have to push it into place and pack it down with a trowel. Just like making a sand castle.

Bagged mortar mixes and some concrete mixes you buy at the box stores may have stone and/or lime in them. You don't want stone or lime in your deck mud that goes on top of the liner membrane, as "regular concrete" can hold water. You want any water that gets below the tile to percolate through the somewhat porous deck mud, hit the sloped membrane, then travel down the sloped membrane and go into the drain through the secondary weep holes in the base of the drain. If he used no kidding concrete? It can work. But any moisture that gets below the tile may simply take longer to escape.

And since I'm on semantics...regarding the "double vapor barrier post" above? I don't believe either Hydroban or Aquadefense are vapor barriers.

Good luck to your and your husband with the shower.

oops. The last few comments came in while I was composing my last tidbit.

Good luck!

Yes mongoct - he used a mix of something and I really should not be speaking to exactly what it was. Definitely looks like concrete. thanks for pointing out that it is possibly the right thing with the wrong terminology. I am going to trust that DH did his homework on this. I really do appreciate all the advice.

Regarding the vapor barrier/waterproofing - we are doing our bathtub surround with hardibacker and tile. One wall is an exterior and has paper backed insulation. So, we assume we can't put plastic or roof paper behind the hardiboard on this wall, due to the double vapor barrier issue. We planned to use Red Guard or a similar product on the hardiboard. Is this ok? I believe the Red Guard is a waterproofing coat, NOT a vapor barrier, so this should be ok. Is that correct?

Correct. Redgard, Hydroban, Aquadefense -- all pretty much the same product from different manufacturers.

OMG!! SO are you saying if its an exterior wall...cant use 6 Mil because of paper back insulation.....really? like, really??? My DH took down all the hardi board and put 6 mil behind it yesterday...are you saying he should now take it down again and remove this?

Please,,,,say it isn't so....he may just divorce me..... LOL!!! (not really funny!)

Oh gabytx12 I hope someone can tell you otherwise. I am sure one of the experts here can advise you further. My husband was the one who mentioned the double vapor barrier issues. I do want to ask someone though, regarding the Redguard, etc. Somewhere when searching the net for where to purchase Hydroban, someone wrote a comment that the hydroban will not stick to hardibacker board. Is that correct? I know that you have to wipe down the backer boards to make sure there is no dust on them, so the stuff will stick. Could that be that person's issue, or is it true that it won't stick to hardibacker board? I want to do this right, so any tips would be appreciated.

this will be the last time I ask for advice on garden web....literally need to do shower over again.... just cost us money and time.....that will teach me to get advice on web....

You can use the poly behind the hardi. Just don't use another barrier on the front of the hardi. You still haven't confirmed if you have a preslope underneath the liner. Just because the final mud layer is sloped, doesn't mean the layer under the liner is.

You should always be careful about advice you seek, whether it's from the internet or the hardware store, or even from a book or magazine. Remember, you don't know who anyone here is or even how knowledgeable they really might be. That being side, the best place for tile advice is the john bridge forum.

I think the concern was using a vapor barrier if you already have one. I am far from expert, but I thought that if you have one vapor barrier on the walls already (and wouldn't the paper backed insulation be considered a vapor barrier?) then you don't want another one on top of that. However, a moisture barrier would be ok, such as the Hydroban, Red Guard etc because they are not vapor barriers, just moisture barriers, . The poly and roof papers are both moisture and vapor barriers I think. Now, if you have insulation in the walls which is not paper backed, it should have poly over it, because otherwise the wall would not have a vapor barrier and you could get all kinds of moisture issues, regardless of whether it is a bathroom wall or any exterior wall. I think. But if you live in the south, you might not even have insulation in the walls at all, so its a non issue. Here in chilly NY we have to insulate our walls. But I do agree, John Bridge is the place to get the best tiling advice, might be a good idea to ask there, gabytx12. It is likely that your "old school" advisor is aware of these things and you don't have to worry. But I'd check it out thru John Bridge, lots of other good information on all things tile there.

"this will be the last time I ask for advice on garden web..."

That might be a good idea. You can get all the information you need using simple web searches. When you depend on an anonymous internet forum you can get all kinds of replies. There are people out there who make a living at construction and they have little knowledge of or little care for the basic guidance contained in the building codes. they are complete hacks. There are DIYers out there who are knowledgeable and do impeccable work.

As to your "two vapor barriers in a single wall"?

6-mil poly is a vapor barrier. RedGard membrane is a vapor barrier. Tar paper, kraft paper insulation, they are not. They are vapor retarders. They may slow the passage of vapor, but they do not block it. Hydroban, as I mentioned before, is not a vapor barrier. It's waterproof, but not a vapor barrier.

I understand your confusion. But I will say it would have been best to have done some basic internet research and if needed ask for advice BEFORE you started any work rather than AFTER.

Now, do not think I'm attacking or insulting you. Trust me, I'm not. Everyone's circumstances are different. I'm trying to add clarification for you and for any readers that may follow.

So OP learned on GW that her DH did a couple things wrong and the solution is to be mad that GW told her the correct way and it will take time and money to fix? Ouch, feels like shooting the messenger.

Keep in mind that rework now WAY beats rework after everything is tiled and your shower won't drain. We're just trying to help here.

No indication of this being an exterior wall was noted previous to any advice. Sorry I am not clairvoyant. :(

I did find a thread with some great info. Something that had me confused was if people are relying on just the insulation vapor barrier, then what about at the bottom? Wouldnt it have to terminate inside the liner? My questions were valid as quoted below, and it makes sense, I like things that make sense. I also like to do a bit of research before I give advice, I prefer not to make things up and then people do the wrong thing.

http://www.johnbridge.com/vbulletin/showthread.php?t=94942

"As I see it, I have three options:
1 - Install the CBU on top of the Kraft-faced insulation, leaving the
paper wholly intact. The only moisture barrier would be the Kraft
facing.
2 - Cut slits into the paper facing before installing the CBU. Once the CBU is screwed in, do a coat of RedGard on the CBU.
3 - Cut slits into the paper facing, install 4 mil plastic, then install the CBU. No RedGard on the CBU.
Which of these three options would be best?"

"Any moisture barrier or waterproofing membrane must terminate inside the tiling flange of your tub.
That eliminates #1.
You can do your choice of #s 2 or 3."

"Is one method generally recommended over the other? "

"Dealer's choice, Tom, both methods are effective.
The direct bonded waterproofing method is gaining in popularity because
no moisture is permitted to go beyond the back of the tiles. Showers
dry out more readily and maintenance is said to be easier. The
differences are more pronounced in full showers than in tub surrounds.
The moisture barrier behind the wallboard is faster, easier, and less expensive."

vithdude-- you'[re right. You CAN NOT rely on the vapor barrier that's part of the insulation for the very reason you stated. Being that it doesn't tuck into the pan membrane, all you're doing is collecting moisture on it, and then depositing it all at the base of the framing, making things even worse by concentrating it all in one place. As was recommended in John's thread, cut slits in the insulation vapor barrier, and then install your own that will tuck into the pan membrane. Personally, the way I see it, the simplest is also the best option-- install with NO additional vapor barrier, and use a surface waterproofing on the face of the backerboard. You can't beat a system that keeps EVERYTHING except the tile and grout, dry.

One last thing-- as for the info above, 15 pound tar paper IS a TCNA approved vapor barrier. AS far as I know, NOT ONE roll on waterproofing, including Redgard, has a permeation rating high enough to be considered a true vapor barrier.

Bill,

#15 felt is a vapor retarder, but not a true vapor barrier. While the numbers always seem to be shifting, to be a vapor barrier a material needs a perm rating of less than 1.0 and #15 felt varies from a perm rating of around 5 when dry to somewhere in the range of 40 to 60 when wet. Tar paper can certainly act as a drainage plane between cement board and wall studs in a tub surround or shower.

RedGard's perm rating is in the range of 0.35 give or take a bit, so it's considered a true vapor barrier. RedGard can be used as a stand-alone vapor barrier in steam showers.

From vithdude: "Concrete board does not mold and wont break down when it contacts water,
but it needs waterproofing above it before tile is layed, either kerdi
membrane or hydroban/redguard/aquadefense coating."

That's half the story. For purposes of a complete conversation I'll add one more point. You can use a topical membrane on the face of the cement board, just as you described. Or you can use a drainage plane of sorts behind the cement board. Most common is 6-mil poly stapled to the studs. Less common is #15 felt, lapped for drainage.

I don;t want people to read your post and think that topical membranes are the only way to go. Topical is a better way to go. But poly is an acceptable alternative.

Well can I put the poly behind the cement board and the Redgard painted on product over it? It might be overkill, I don't mind that as long as it doesn't cause problems. My issue is with the wall that has the paper backed insulation on it. I can't take the insulation out of course, and I can't really tear off the paper as it will pull of some of the batting with it. My thought was to apply Red Guard to that wall, and maybe poly and redguard on the other 2 non exterior walls. Will the redguard on the exterior wall cause a problem, such as trap moisture between the hardibacker and insulated wall? Do I need to cut slits in the insulation paper if I just Redgard the hardibacker? Or should I just paint the Redgard over all 3 of the tub surround walls? It sounds like Redgard and hydroban are the same type of product, either one would be sufficient? Sorry for all the questions, but I want to do whatever is best, I want this tiling job to last.

Red Guard or Hydroban on the hardiebacker OR poly behind the hardie backer not both. I used hydroban because I like the laticrete line of products but i've never heard of problems with Redguard. As far as the insulation goes I don't know. There is debate about that even if there is no shower wall there. If you live in warm climates it goes near the outside of the wall assembly, ifcold climates, on the inside wall assembly. But I've read the opposite too.

Personally, I would use hydroban and there will be no moisture getting into the wall from your shower. You need to put on 2 nicely applied coats without thin spots. It should look nice and olive colored without blotchiness.

As far as cutting the insulation barrier, I can't advise.

I'm going to assume that Mongo is right, and I've missed something with respect to the Redgard specs. I'm not a big fan of Custom building Products, so my knowledge of their products isn't the best. If the Redgard is good enough that it can be used as a vapor barrier as well as a waterproofing, then no you can NOT use both. That's when you get the moisture sandwich. However, with the Hydroban, which can NOT be used as a vapor barrier, yes, you can. it's not necessary, though-- trust me-- there's not enough steam in a standard shower to push vapor thru the Hydroban. And with the Hydroban, you don't need to worry about cutting the slits, either.

Edit-- one last thing-- as for lasting? My showers all get a 25 year manufacturer backed warranty using the Hydroban as the waterproofing part of the system.

I have created a top five list of the best waterproofing materials for 2015. You can see the complete list here:

Top Five ANSI 118.10 Waterproofing Materials

And what are the requisites to make your list, John?