I just found out the plywood info:

Apparently, the plywood that is going down on the sleepers is:
3/4" Tongue and Groove underlayment

This will make the sub-floor of the bathroom about the same height as the existing floor in the finished living area of the basement.

thanks.
mm

I am not an expert, but I did a lot of research prior to beginning some tile work I am doing in a home remodel. My understanding is that tiling directly over plywood is not a good idea. The concern is that the subfloor (the plywood and 2x4s underneath) will naturally have some flexibility. Tile and thinset has very little. As your house moves naturally (and they all do) there is a chance that the tile and/or grout will crack.

I believe that you should either have cement board adhered (thinset? or some construction adhesive? I'm not sure) and screwed on top of the plywood OR better yet, use Schluter Ditra over the plywood. Ditra is an isolation membrane (and waterproofing, and supporting membrane) that creates a physical bond (rather than a chemical bond) with the thinset holding the tile down. It will allow movement of your home without cracking of tile. I just installed my new tile floor using Ditra and I was impressed with how easy the installation went. Simply lay out a thinset bed (latex-modified under the Ditra) and comb and then lay down the Ditra and bed it using a float. Then tile directly over that (using non-modified thinset).

I have heard Ditra recommended by most of the professionals on this site, and my tile shop also highly recommended it. In fact, the installers at my tile shop said they've had cracks in the past with non-Ditra installations but never with Ditra installations.

Okay-- I'm going to take this a little bit at a time, because there are several issues here. First, let me start with PPC's post, because she has some valid points, and some not so valid:

My understanding is that tiling directly over plywood is not a good idea. The concern is that the subfloor (the plywood and 2x4s underneath) will naturally have some flexibility. Tile and thinset has very little. As your house moves naturally (and they all do) there is a chance that the tile and/or grout will crack.

First, regardless of what you hear, tiling directly over plywood is not a problem, if it's done right. Problem is not very many people know how to do it right. Including your friend. The very FIRST spec in ANY tile floor, no matter what the bonding surface will be, is that there MUST BE ATLEAST TWO LAYERS. Tile over a single layer of plywood, and you'll see grout joints and tile cracking within 3 months, and that's guaranteed. If you REALLY want to tile over plywood, here are the specs, as written on my website's FAQ Page. The question asked was What are proper underlayments for tile, and the following is the "plywood" portion of the answer:

3. Plywood This is one where I get the most flack. IÂm one of a dying breed that still believes in tiling directly over plywood. However, I can very well understand the reluctance of the industry to embrace this installation method, even though the TCNA DOES approve of its use for interior installations (Those with a handbook can check Method F-149). The reason I say that is itÂs a very "temperamental" installation method. You need to be very familiar with what youÂre doing, or you risk failure. There are even many pros I wouldnÂt trust to tile using this method. Everything you do is important, from the species of plywood used, to the direction the grain is laid with relation to the joists, to how itÂs gapped, and a host of other specs, as well many of which wonÂt be found in the handbook, and if you miss just one of them, youÂre flirting with disaster. All in all, when people ask me about it, I tell them that with the membranes available, thereÂs no need to go directly over plywood. There are other methods that will give you just as long lasting a floor, and arenÂt NEARLY as sensitive. For those who still want to tile directly over plywood, though, Here are the specs. Shortcut any one of the specs I'm about to give you, and you can kiss that floor good-bye:

There needs to be two layers of plywood, the top layer being spruce or fir (preferably fir), exterior grade BCX or better. The layers need to be screwed (spec calls for every 6" along the edges, and 8" in the field-- I go every 6" throughout, ONLY into the bottom layer-- NOT into the joists) BUT NOT GLUED. When laying the second layer of plywood in, make sure the joints of the top layer fall at the 1/4 and 3/4 mark from the layer underneath. You don't want the joints in the two layers to be any closer than necessary. Also, when laying them in, leave about a strong 1/16" between the sheets for expansion, and make sure you're laying it in with the grain going across the joists. Make sure, when screwing down the top layer, that you're going no further than the bottom layer of plywood. DO NOT drive the screws into the joists. This completely negates the effect of double layering the floor by transmitting the movement from the joists right to the top layer of plywood. Once it's all screwed down, take any cheap latex caulk you can find, and caulk the joints between the sheets of plywood. The reason for this is those joints are for expansion, as I said before. Now you're going to go over the plywood with thinset. Sorta kinda defeats the purpose of gapping the plywood if you fill that joint up with thinset. That's ALL the caulking is there for-- to fill the joints with something that will remain pliable and at the same time, keep the thinset out. Last prep spec is that just like with cement board, you need to use a fiberglass mesh tape to bridge those joints . Easiest to use is the self sticking tape, and then just go over it with thinset when you set the tile. Last thing that's different and this is paramount-- the thinset. Just about ANY bag of modified thinset will tell you it can be used to go over plywood. DON'T BELIEVE EM!!!!! The ONLY thinset I'll trust is an UNmodified thinset, mixed with a liquid latex additive, full strength, such as Laticrete's 317 thinset mixed with their 333 additive, or Mapei's Kerabond thinset mixed with their Keralastic additive. The reason for this is it'll give you the highest latex content possible in a thinset, which does a couple of things for you. It's the strongest stuff you can find, and it's also the most pliable, so that it'll take the extra expansion and contraction that plywood goes through, as compared to cement board.

The next thing I have a problem with actually solves one of the problems PPC brings up, but it comes with problems of its own, and that's tiling over a subfloor built on sleepers. It solves the problem of structural movement from the house, because the sleepers are in no way connected to the structure. If done properly, not even the floor beneath them. So the sleepers will completely isolate the tile from structural movement. Where the problem comes in is moisture in the voids created by the sleepers wreaking havoc on the 2x4's. Well, then you could use PT lumber, right? Wrong. They'll twist even WITHOUT moisture.

I believe that you should either have cement board adhered (thinset? or some construction adhesive? I'm not sure) and screwed on top of the plywood OR better yet, use Schluter Ditra over the plywood.

Not that Ditra or cement board would make any difference in this case, but I wanted to clear up a few misconceptions here. First, the very WORST thing you could do with cement board is to use construction adhesive. The whole reason for thinset under the cement board is NOT to bond it to the subfloor. It's to act as a cushion, or bedding for the cement board, to remove the paper thin voids that would exist between the two layers and drastically shorten the life of the floor. The screws are what holds the cement board down. Using construction adhesive is actually worse than having nothing under the cement board at all, because it actually CREATES the voids you're trying to eliminate.

Ditra is an isolation membrane (and waterproofing, and supporting membrane) that creates a physical bond (rather than a chemical bond) with the thinset holding the tile down. It will allow movement of your home without cracking of tile.

Ditra will not protect against the movement that would exist from using sleepers. That can be pretty extreme.

Now back to the OP. On the shower walls, I noticed there was no mention of a vapor barrier or waterproofing membrane on the Durock. You need one or the other. Either tar paper or polyethlene between the studs and Durock, or a roll on waterproofing (or Kerdi) on the face of the Durock. One or the other. Your choice.

Bill --

Thanks for your informative reply....

I have a few follow-up questions.

First, the shower.
I will make sure they do either the polyethlene or the roll-on waterproofing.
I see that you said that it's my choice, but which do you think is better? Any reason to choose one over the other?
If I do the polyethlene, what is the proper way to attach it to the studs? Staple gun?

Now, to the floor...

I now understand that they need to add another layer to the floor. I will make sure they use Doug Fir and get it at least 1 1/4" thick. Screw it down with stainless steel screws (not in the joists)....as well as follow the other tips you stated....

But this is where I am confused and worried..........
Are you saying that no matter how they prep the floor or what type of underlayment they use, that the tile job is doomed because of the effect on the 2x4s caused by moisture/dampness in the voids created by the 2x4 sleepers? Hopefully I was just reading you wrong....

thanks.
mm

I will make sure they do either the polyethlene or the roll-on waterproofing.
I see that you said that it's my choice, but which do you think is better? Any reason to choose one over the other?

The poly or tar paper is code and will suffice, and is much cheaper. But the waterproofing, especially being that it's surface applied, is much better, albeit more expensive.

If I do the polyethlene, what is the proper way to attach it to the studs? Staple gun?

Yes.

Are you saying that no matter how they prep the floor or what type of underlayment they use, that the tile job is doomed because of the effect on the 2x4s caused by moisture/dampness in the voids created by the 2x4 sleepers? Hopefully I was just reading you wrong....

Unfortunately, no, you're not reading me wrong. It's never a good idea to tile over sleepers. Period.

Bill --

Hmmm......well that stinks.

Unfortunately, I don't have a choice as I see it.
The current existing finished basement is up on sleepers now.
In order to avoid having a step down into the bathroom, I used sleepers.

So, are there any other measures or steps I can take that may prevent any problems?

thanks for the help.
mm

MUDJOB!! :-)

Seriously-- find a tile guy who knows how to float the floor with dry-pack. You couldn't ASK for a better substrate. I literally PRAY for jobs like this!

Thanks for the help, Bill...

Bill --

I will look into the mudjob....just got to try to find a reputable tile guy in my area....

But I did find out another piece of info....

Does the fact that the 2x4 sleepers are attached to the concrete with PL glue and Red Tapcon screws change your opinion? Shouldn't the combo of glue and screws hold the 2x4s in place and minimize movement?

just wondering....thanks for the help.

mm

Nope, not even a little bit. Where abouts is your area? I might know someone.

I am in Fairfield County, CT.

Bethel/Danbury/Newtown area

Bill --

My wife and I were talking.....discussing options...etc.

What about something instead of tile?

We would prefer not to do vinyl/linoleum.....but what a engineered hardwood floor? Or maybe laminate?

thanks...
mike

I can't speak to any of those. You know as much about them as I do. I don't see any reason why you can't float the floor, though. It'd bring it up to the height you want, and be a much stronger floor.

Bill --

I have a local tile guy coming to the house this afternoon to look at the job.

But, I was thinking about my situation last night....

Why wouldn't putting down some sort of vapor barrier (either heavy mil plastic or a roll-on product like HydroBan) underneath the 2x4 sleepers? Wouldn't that keep moisture from coming up through the concrete?

thanks.
mike

Bill -
well...i think (actually I know) I am gonna take your advice and have a professional tile guy do this job......pay now or pay later. id rather pay now.
got a quote from a local guy to do the job.....he's a friend of my plumber....
His price for the job is $1360.00
Includes: mud bed for floor, (including bonding agent on concrete and wire mesh to strengthen the mud bed), set floor tile on diagonal. set shower tile all the way to ceiling, one shower niche with shelf.
The only thing I have to do for him is put up the plastic or tar paper on the shower wall studs, then Durock or Hardiboard.
Floor: approx 70 sq ft
Shower: 34x48, with tile all the way to 7' ceiling (but not on the ceiling)...approx 70-80 sq ft.
I got another guy coming for a quote tonight.....but unless he blows his price out of the water, I am gonna go with my plumber's friend.
the saga continues.....
mike

If the prices are way far apart, get a third quote. There might be a reason for it. As I've told my own customers who've shopped my price-- the other guy knows what his work is worth. :-)

The third price would be the "spoiler", though. It'd let you know which price is more in line with your area.

Update......3/16/2010.

I am gonna use the first tile guy that came out (friend of my plumber). Nice guy, very attentive to my questions, etc.
The second tile guy that came out said he guaranteed I will have no porblem tiling on the sleepers over concrete. RED FLag!? He said he would email me a quote......he never did. oh well.

When I order the tile yesterday, I told the ladies at the tile shop who my tile contractor was....they spoke very highly of him....calling him a perfectionist....hopefully that bodes well for me and my bathroom.

So here are the new specs.....
Bathroom floor:
Mud Bed
[including bonding agent on concrete and wire mesh to strengthen the mud bed]
tile se on diagonal
Radiant heat floor set in mudbed
Thinset
Tile

Shower:
Swanstone Shower pan [34x48]
Durock walls
Thinset/tape seams
Mapei liquid waterproofer (either HPG or AquaDefense)
One recessed niche
tile to ceiling

Look ok?

TWO Questions:
1. Any preference for either Mapei waterproofing products? The HPG or AquaDefense?
2. Question on vapor barrier for foundation wall
One wall of the bathroom is on the poured foundation wall. Do I need a plastic between the cement wall and the insualtion and studs?

thanks.
mike

1. Any preference for either Mapei waterproofing products? The HPG or AquaDefense?

If it's got to be between those two, it'd be Aquadefense. But I prefer Laticrete's Hydroban. Same kind of product, but I think a better one.

2)No-- you need plastic between the studs and cement board, unless you're going to waterproof the face of the cement board.

Bill --

Mud floor is going in today.....i'll post pics when it's done.

Stil undecided on the liqiuid membrane.....
So many choices, so many varied opinions out there on the liquid membranes......
RedGard, HydroBan, WaterTight, HPG, AquaDefense........ugh.
Someboday on another message board said this about the memberanes:
"Although the above products are waterproof they are not considered as vapor barriers. Only RedGard has a vapor barrier rating.
If you use anything other than RedGard or Schluter Kerdi, then you could install a vapor barrier on the exterior wall studs.
Others are adamant that any waterproofing should not have a vapor barrier and topical waterproofing together for fear of the "moisture sandwich.""
Thoughts?

Sorry.....question #2 regarding insulation/vapor barrier above was unclear....it was not in relation to the shower actually....
It was more of a general construction and insulating question.
The shower is not on the exterior poured concrete foundation wall. The toilet and vanity are on the foundation wall.
I was thinking of putting up rigid foam agianst the concrete wall, then fiberglass batts on top of that....any thoughts?

thanks Bill...

mm