Basement Bathroom Tiling Installation Questions

[mrmichaeljmoore]

I am having a full basement bathroom installed and just wanted to ask a few questions regarding tile installation.
Half of the basement is already finished. So, we will be breaking through the wall that separates the finished from the unfinished side and adding a bathroom there.

My friend is a contractor who is doing the work, including tiling (except electrical and plumbing).

Here is his plan he gave me for the tile installation.
He said he and his guys are good a the tile work and he even offered to show me jobs he has completed....

Floor:
2x4 sleepers to get the bathroom level with current finished area
Plywood subfloor (3/4" tongue and groove underlayment)
Plywood screwed down (apparently he said they use a lot of screws to secure the plywood)
Thinset and Ceramic Tile over plywood floor

Shower:
Swanstone shower base (bulit up on same sleepers and plywood as rest of bathroom floor)
Quikcrete Sand topping mix under Swanstone base for support
Durarock walls
Thinset
Ceramic Tile
NOTE: 2 of the 3 shower walls will be exposed on the backside. The third wall will be the inside wall of an adjoining closet.
Question: What should I use for a vapor barrier? Plastic sheeting behind the Durock or a roll-on membrane applied to Durock?

I have read that tiling over 2x4 sleepers on concrete is a bad idea.....
Apparently, moisture/dampness in the voids created by the sleepers can cause movement in the 2x4 sleepers...thereby possibly causing cracked tiles/grout. True? Any remedies for this?

Overall, does the plan look good? Any criticisms or suggestions would be helpful.....

If more info is needed, please let me know and I wil provide.

Thanks.
mm

[jadnashua]

There are approved methods to install tile over plywood, but the method you depict is not an approved one. If you want to use plywood, and not use some other decoupling layer, you have to have two layers of ply then use a pretty expensive highly modified thinset. the second one can be 3/8" and should not have a side lower than 'C' (i.e., D allows voids which are death to tile). Over a single layer of ply (assuming ceramic tile and not natural stone), you could install cement board, or use a decoupling membrane such as Ditra from www.schluter.com to minimize the buildup. check out www.johnbridge.com for more help on tiling.

With the 2/4's in contact with the concrete, if moisture is a potential problem, you should use KDAT 2x4 (kiln dried after treatment) pressure treated wood. The subflooring should be 'normal', though. "Normal" treated wood is still VERY wet, and will often warp or twist when it eventually dries out. If the floor isn't flat, you may need to do some extra work to get the sleepers to be fully supported and not rock while keeping the floor nice and level and flat.

An alternative for those tiled areas would be to use deck mud - this would level the floor and give a great surface to support the tile. It's probably cheaper than buying the wood and then you wouldn't have any issues with the wood and moisture. Deck mud is mostly sand (that's why it's cheap) with a little portland cement to hold it together. It gets packed and screeded down like damp beach sand - it doesn't flow.

[mrmichaeljmoore]

Thanks for the help....

I talked to the contractor....
He said the 2x4s are pressure treated (not sure if they are KDAT though).
They are attached to the concrete with PL Construction GLue and Red Head Tapcon screws.... shouldn't that hold the 2x4s in place pretty good??
Walking across the floor right now, it seems real solid....

I am gonna try to look into the mudjob option.....but I bet that is gonna be real expensive....

I will definitely add another layer of something to the plywood.
I may try to go with 1/4" Hardiebacker set in thinset...it was recommended to me by the local tile shop.
And, yes, we are doing ceramic tile....

Thanks for the help.
mm

There are approved methods to install tile over plywood, but the method you depict is not an approved one. If you want to use plywood, and not use some other decoupling layer, you have to have two layers of ply then use a pretty expensive highly modified thinset. the second one can be 3/8" and should not have a side lower than 'C' (i.e., D allows voids which are death to tile). Over a single layer of ply (assuming ceramic tile and not natural stone), you could install cement board, or use a decoupling membrane such as Ditra from www.schluter.com to minimize the buildup. check out www.johnbridge.com for more help on tiling.

With the 2/4's in contact with the concrete, if moisture is a potential problem, you should use KDAT 2x4 (kiln dried after treatment) pressure treated wood. The subflooring should be 'normal', though. "Normal" treated wood is still VERY wet, and will often warp or twist when it eventually dries out. If the floor isn't flat, you may need to do some extra work to get the sleepers to be fully supported and not rock while keeping the floor nice and level and flat.

An alternative for those tiled areas would be to use deck mud - this would level the floor and give a great surface to support the tile. It's probably cheaper than buying the wood and then you wouldn't have any issues with the wood and moisture. Deck mud is mostly sand (that's why it's cheap) with a little portland cement to hold it together. It gets packed and screeded down like damp beach sand - it doesn't flow.

[jadnashua]

If you already have the sleeper system down in place, you shouldn't do the mudbed, as you'd have to tear that out. A mudbed needs to be at least 1.5" thick (more is okay), and I'm sure you don't want to raise it that far. It would have been in place of the sleeper system, not on top of it.

[mrmichaeljmoore]

If you already have the sleeper system down in place, you shouldn't do the mudbed, as you'd have to tear that out. A mudbed needs to be at least 1.5" thick (more is okay), and I'm sure you don't want to raise it that far. It would have been in place of the sleeper system, not on top of it.

Yeah, I realize that the current sleeper/plywood subfloor will have to come out if we decide t do the mudbed....

But if thats the case to make it right and prevent any major problems, and maybe a major ripout and redo....then maybe thats what'll have to be done.

so, what do you think? should i just go with what i have (2x4 sleepers, 3/4" plywood underlayment and 1/4" haridbacker on top, then tile...........or should I rip it out and go with a mudbed?


ugh..........

[mrmichaeljmoore]

well...i think (actually I know) I am gonna 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

[mrmichaeljmoore]

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?

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

thanks.
mm