Ceramic Tile Advice Forums - John Bridge Ceramic Tile

Welcome to John Bridge / Tile Your World, the friendliest DIY Forum on the Internet


Advertiser Directory
JohnBridge.com Home
Buy John Bridge's Books

Go Back   Ceramic Tile Advice Forums - John Bridge Ceramic Tile > Tile & Stone Forums > Tile Forum/Advice Board

Sponsors


Reply
Thread Tools Search this Thread
Unread 02-24-2004, 01:22 AM   #1
luna95
Registered User
 
Join Date: Feb 2004
Location: pittsburgh
Posts: 5
flexibond vs ditra? and other ?'s

howdy.
okay, the fact that i'm up at 0200 still reading says something about my situation, doesn't it? well, maybe not, but i've still got questions.

1) i'm now uncertain about what to do for my tile install, esp with my floor tiles. we live in a condo with prestressed concrete planks, about 4' wide. these planks have settled over time and now are pretty uneven (1/4" from one to the next). i've put down leveler and was planning on just using flexibond, but after reading the virtues of ditra and being concerned about movement...? basically, is flexible thinset good for anything? my priority is trying to maintain as low a profile as possible, hence reluctance to put anything additional down.

2) i'm carrying the tile pattern (sorry no pics...ebaying for a digital camera right now) from ceiling, across floor, up opposite wall (simply, like a "U"). the pattern is 18"x9", short end to short end. in doing this, i'm trying to create the appearance that the wall tile just continues onto the floor, with minimal/no grout. is this possible/advisable, or do i need to put in an expansion joint? i read the liberry article on these, but was a little unclear still.

3) i'm using vitreous porcelain (keope brand, +stone line) and was wondering why most references in tiling are about ceramic installation. is porcelain so uncommon, or are they similar enough not to warrant a seperate mention?

4) the tiles have built in spacers (i think...) which when butted against each other, create a pencil thin space, but not a more "traditional" 1/4" or similar. is tile spacing simply a matter of personal preference, or are there recommended spacing for different applications?

5) do i need a vapor barrier on an interior shower wall (52"x10")made from CBU? felt? or will the CBU w/thinset and tile suffice?

i apologize for being so wordy, but i figure it's best to front load, and minimize the need for clarification later on. thanks in advance for any and all advice. i'm sure i'll have more later; i've got a whole 'nother bathroom to do still! this place rawks.

jason
luna95 is offline   Reply With Quote
Sponsored Links
Unread 02-24-2004, 03:34 AM   #2
luna95
Registered User
 
Join Date: Feb 2004
Location: pittsburgh
Posts: 5
okay, i'll answer

well, just when i thought i was going to bed, i read for another couple of hours and found some things out; tell me if i'm on the right track, or on the crack rock.

1) Flexbond ain't gonna cut it for subfloor movement. But will the SLC act as any type of decoupler?

2) I think I need an expansion joint? but does it depend on the size of the room? (bath is about 9 x 6 at its largest, but not a perfect rectangle)

3) still stands

4) still stands

5) still stands, but to clarify, not a vapor barrier out of CBU, but behind it; the wall's CBU. duh.

BTW, I'm using all the same tile, so I'll probably need to go with the Flexi b/c of the tile weight on walls?
luna95 is offline   Reply With Quote
Unread 02-24-2004, 06:52 AM   #3
bbcamp
Registered User
 
Join Date: Jul 2002
Posts: 30,274
Welcome, Jason!

1) I think the joints between the prestressed planks should be considered expansion joints. I think you've seen why. The vertical displacement will prevent you from tiling over the joints. I don't know if pre-made expansion strips will handle any more movement than you've had, and will likely have again. You're right, thinset alone won't handle it.

2) You will make a joint between the walls and floor. This joint will be caulked instead of grouted.

3) Procelain is a ceramic. Most procedures are the same.

4) General rule: the thinner the line, the harder to set. More grout line gives you some flexibility in setting the tiles to account for tile dimensional variation and un-flat substraits.

5) Yes, you need a vapor barrier behind the CBU, unless you decide to paint on a surface water-proofing membrane over the entire shower.

You can use modified thinser on almost any portion of a tile job. In some cases it is a little overkill (I prefer "insurance"), and other cases it is mandatory. About the only time I've heard where you don't want to use it is when installing porcelain over Ditra.

Bob
bbcamp is offline   Reply With Quote
Unread 02-24-2004, 09:13 AM   #4
luna95
Registered User
 
Join Date: Feb 2004
Location: pittsburgh
Posts: 5
oh yeah, and also...

Thanks for the welcome. One detail that just occurred to me as I read your reply was that the bathroom floor was already tiled prior to the remodel. What I encountered on demolition was that the 3x3 terra cotta glazed tiles that were down before popped up very easily. I attributed this in part, however, to a pretty poor leveling job the first time around (prior ownership). As I look in the other bathroom, which has the same type of tile setup, there really aren't any cracks or shifts in the joints, nor is it out of level, which tells me that most of the settling has stopped? That's why I thought I could get away with just priming and SLCing, then going to Flexi.
Although leakage is a large problem in our bldg right now, but it's due more to rain, and what's happening on exterior walls, with water intrusion.
Anyway, I guess what I'm getting at is that I thought since it was tiled before, with what I assumed to be a poor leveling job (it just chipped right up in large patches), that I could do a proper leveling job, and then tile on. But you say expansion joints, and not even using a decoupler is what I'll have to do?
(Just wait until I get to the next bathroom with the planned mud pan and mosaics and terrazzo )
luna95 is offline   Reply With Quote
Unread 02-24-2004, 05:30 PM   #5
John Bridge
Mudmeister
 
Join Date: Mar 2001
Location: Rosanky, Texas
Posts: 67,831
Send a message via AIM to John Bridge
Hi Jason, Welcome.

One brand of the concrete planks you're talking about is "Span-crete." The sections are keyed into each other along their edges. There's no question Bob is right in that they should be considered movement joints. It's sort of like having a slab with wall-to-wall cracks running through it on four foot centers.
John Bridge is offline   Reply With Quote
Unread 02-24-2004, 09:32 PM   #6
luna95
Registered User
 
Join Date: Feb 2004
Location: pittsburgh
Posts: 5
I'm a little confused now. So basically I just need to put expansion joints *directly* over each seam in the planks? The tile runs I'm planning are parallel with the plank joints. And would the caulk method of expansion joints be the preferred method? Would this preclude the use of ditra (or any other decoupler)? I'm just trying to get things in order here. I thought I was ready to tile yesterday.
luna95 is offline   Reply With Quote
Unread 02-25-2004, 10:18 AM   #7
John Bridge
Mudmeister
 
Join Date: Mar 2001
Location: Rosanky, Texas
Posts: 67,831
Send a message via AIM to John Bridge
Yes, if you could arrange a grout joint over each seam, all you would have to do is bond the tiles to the concrete and then use matching caulking in the joints over the seams when you grout. The problem is your joints probably won't come out exactly like that, and you may have joints that are two to three inches off the seams. If this is the case you would have to have a membrane under the tiles on both sides of the seam. Since your seams are only four feet apart, it might make sense to have the membrane over the entire floor.

An alternative would be to cut joints into the tiles directly over the concrete seams. That would be very unsightly in my opinion.

It turns out that span-crete just isn't a very good substrate for tile.
John Bridge is offline   Reply With Quote
Reply

Stonetooling.com   Tile-Assn.com   National Gypsum Permabase


Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Forum Jump


All times are GMT -6. The time now is 08:20 AM.


Sponsors

Powered by vBulletin® Version 3.7.4
Copyright ©2000 - 2020, Jelsoft Enterprises Ltd.
Copyright 2018 John Bridge & Associates, LLC