My contractor and tile guy are engaged in a philospohical discussion on the highest quality method of cermaic tile substrate
One side says Waterproof paper/Wonderboard/Thinset/Tile
The other says Waterproof paper/Greenboard/Mud/Thinset/Tile
As the client, I amost interested in longevity, rather than short term cost – anyone with any experience of these matters care to edify me?
Replies
ixnay on the eenboardgray!
"The child is grown / The dream is gone / And I have become / Comfortably numb " lyrics by Roger Waters
If the tile guy is saying use green board get a new one, if the contractor is saying use greenboard tell him to listen to the tile guy.
You can use greenboard in back of tile but it is much more susceptible to damage if the grout fails, the green board in constant contact with the water will fail.
Concrete board will not.
Tell the guy who is suggesting to use green board to take a bucket and fill it with water and put a piece of greenboard and a piece of cement board in there and ask him to get back to you in a day or two as to which one is better.
Beyond the water issue thinset will grab onto and stick to the rough surface of the cement board then it will the greenboard.
To sum it up? Using drywall even water resistant in the shower is dumb.
Thanks - you have summed it up succinctly ..
We have decided to use Dens-Shield - a proprietary backer material (from Georgia Pacific) which makes amazing claims. I am glad we had the philosophical discussion - we ended up with a better project.
Go Cardinals!
green board is just moisture "resistant" drywall.
and drywall has no place behind any tile that's gonna see water.
Are U talking backsplash...or shower.
or something in between.
I'd only consider green board on a kitchen backslpash.....
and what "waterproof" paper are they talking about?
again...to be used where? Guessing shower.....and plastic or felt should go on the walls...as a moisture barior and drainage plane....
But a waterproof pan must be constructed...several ways to do so....none invloving a "waterproof paper". I prefer a rubber membrane encased in the mortar bed. And it's more invloved than laying some rubber in some mortar.
What's the specific application?
Jeff
Buck Construction Pittsburgh,PA
Fine Carpentery.....While U Waite
How would you handle this?
Building a large-2 person-shower. If one puts the rubber membrane on the substrate and then builds a morter base, the morter base drains to the drain, weep holes, but the membrane doesn't drain, as it is flat. Is that how its done, or does one first build a morter bed, put down the rubber, and then build another morter bed on top of that?
Stef
custom shower pans are a major portion of my tile work.
Me.....I get there after the framing is up....and they usually also set the backer board on the walls too. The felt of plastic goes under the backer.
I have them leave the backer about 6 inches high off the sub floor and run the plastic/felt down over lapping the floor.
I work right off the plywood subfloor. I build the curb outta 2x stock to the prefered width and planning for the desired height. The height is usually affected somewhat but the tile to be used.
I then pour a dry pack mud bed right on the ply. This first pour is to set the pitch. The slope's bed should go down first...sloped to the 2 part clamping drain..already installed.
After that sets.....usually the next day....me or the plumber lay's the rubber membrane and clamps it in the drain...and extends up the walls about 6 inches...that's why the backer has been left short..and corners folded....and run op and over the curb. No nails anywhere but high and outside curb. Makes for a little rubber swimming pool. See...now your rubber is sloped to the drain too...instead of sitting flat and inviting stagnant water.
The drain is then unthreaded up...extended....and I detremine how thick to make the second layer of mud. I like to stay around an inch. Once again..site and designer affect each one.
Then......a layer of diamond mesh.....cheese and skin grater stuff.....is layed over all the rubber.....bent to fit tight and practically hold it's self in place...again up the walls and bent tight to go up and over and down the curb.....like an upside down U..that clamps itself over the curb/rubber.
I make that fit so no nails are needed. Overlap when one piece is too short.
Now...comes the second layer of mud. I usually pour the floor/walls as one and the curb seperate..but smaller showers allow for one big pour. The floor is packed.....the base of the walls is filled and plumb to the backer.....run the trowel on edge for a nice square floor/wall joint.......floor at wall base's is all checked and screeded for level....floor from walls to drain is double checked for pitch.....
I'll set a 2x as the form for the inside and outside curb...I like to measure and cut so the forms are level(actually slightly picthed to the inside) across the top(short ways) and the whole curb is level across the top(long ways) so the shower door sit's near perfect.
I don't care if the curb or the bath floor goes in first...I've done it both ways.
Use grout caulk to match the grout anywhere there's a joint that's not flat...ie..corners...fixtures....etc.
My painter like to paint over the grout caulk last so I can run the caulk messy onto the ceiling if the tile dies into it and he cuts a nice straight line.
Same for the side wall bullnose.
I'm tired...but I think that covers most of it.
http://www.johnbridge.com That's a great tile website. Has a forum for pro's and a seperate area for homeowners to ask questions. Reading the pro threads should help ya too.
The method I use is pretty much straight from the TCA handbook. That's the Tile Council of America. They might even had it laid out on a web site somethere.
Hope this helps and makes sense...haven't proof read.....like I said..I'm tired and off to a hot bath.....too long a day busting out an old tile job!
Jeff
Buck Construction Pittsburgh,PA
Fine Carpentery.....While U Waite
Whoo, buddy, thanks!
That was heavy, but I bookmarked it so I can read it over and over. I think I have it.
Thanks for staying awake long enough to write that, I do appreciate it.
Stef
Jeff
I'd hate to rip out one of your shower floors...lol
I usually put down the rubber right on the subfloor and tucked into the drain then I do my mud job pitched 1/8" per foot towards the drain then tile.
The extra step you take with the first layer of mud makes sense though.
I just started using Ditra instead of wire or rubber. I know the people at all the tile sites seem to be in love with it which is why I started using it.
Sure is easy to work with. The price is pretty hefty but if its as good as its supposed to be then it is well worth it. Especially if youre doing large areas and up flights of stairs.
Have you played with it yet?
In his first interview since the stroke, Ram Dass, 66, spoke with great difficulty about how his brush with death has changed his ideas about aging, and how the recent loss of two old friends, Timothy Leary and Allen Ginsberg, has convinced him that now, more than ever, is the time to ``Be Here Now.''
http://CLIFFORDRENOVATIONS.COM
I noticed you guys did mention floating the floor with concrete. I personally like the backer board but some guys still float.
Darkworks: Its all 'bout da squilla
Greenboard is perfectly acceptable substrate for Mud.
Greenboard, 6 mil poly, lathe, mud, thinset and tile. It is done all the time.
I don't fault any of you for not understanding mud jobs, it just isn't done that often on walls. But you need a flat substrate for the mud, and the rock is perfect. It won't see a drop of water, between the mud and the poly. The only other substrate would be plywood, and if the logic is carried over, that would swell wouldn't it? The concept is that the mud is separated from the greenboard with the 6 mil poly (or use 15 lb felt). Like I say, it is done all the time.
I don't believe there are many quality differences between a mud job and backerboard on walls. Mud is handy in old homes where walls are wavey and corners are not square. Mud can be made perfectly flat, square and plumb.
CBU's can replicate mud BUT.... It can be a pain to get them perfectly flat, plumb and square. Lotsa shimming and scratching ones head.
I use CBU's 90% of the time because the walls are not off that much.
I want to emphasize that this post applies only to walls, not floors. And if the application is in a shower, a previous poster had it right on the membrane. Do a preslope, then a membrane and take the membrane 2-3 inches above the level of the curb. The CBU's or the Mud go up and over the membrane.
Regards,
Boris
"Sir, I may be drunk, but you're crazy, and I'll be sober tomorrow" -- WC Fields, "Its a Gift" 1934
Edited 4/30/2003 12:46:47 PM ET by Boris Yeltsin
I agree with you on mud jobs but the one described in the beginning was to place mud over the greenboard with plastiv behind it. Moisture that goes through the mud will be locked agaist the greenboard and destroy it quickly. Your procedure isolates the greeenbd from moisture. I would use tarpaper instead of poly tho.
I'm interested in this Ditra too though. I saw something similar used on a job about fifteen years ago for a second floor bath to seal it in. I know it was like a hardening rubber, gray colour, and expensive. I've still got some aadhesive coating from it stuck to a tool handle! It must have worked too because the owner built himself a wooden Japanese bathtub. Guess what? He learned the hard way how to waterproof it..
Excellence is its own reward!
Ditra is for floors, not walls.
Ditra is not a waterproofing membrane, it is a "de-coupler". Its main function is to separate the substrate from the setting bed. Like plywood and cracked concrete. Normally not very good setting beds, but apply Ditra over it, and it "de-couples" the tile from the plywood.
For waterproofing, try anyone of the liquid membranes, like Laticrete 9235 or the Thorough Seal products (I forget the name); sheet membranes like Noble CPE or Nobleseal or PVC, or Schulter's Kerdi. Anyone of these will work fine on floors.
For shower floors, I would only use PVC or Noble CPE.
Regards,
Boris
"Sir, I may be drunk, but you're crazy, and I'll be sober tomorrow" -- WC Fields, "Its a Gift" 1934
haven't used ditra....
read up on it a bit after U mentioned it before....
I sub for the same guys....and they all like the same system....so I'll probably not have a good excuse to try it unless I run into something on my own.
most of my showers are thru 2 GC's....never the same shower twice.....but always the same system getting there.
Alotta people don't like the mesh and mud...but it's what I'm used to.....
and I clot pretty fast when the mesh grates my fingers off.
JeffBuck Construction Pittsburgh,PA
Fine Carpentery.....While U Waite
Schluter's Ditra is meant to be used as an isolation membrane between substrate and tile, in a flooring application. Schluter does not recommend it as a product for use in shower floors or shower walls.
The Schluter product for use under tile in showers, both floors and walls, is Kerdi. The Kerdi product line includes a drain fitting and flange that is meant to go together as a system with the membrane. It is very well made, with cool features that tilesetters like.
For a good little product trial, build a cheap box with some scrap OSB, say 16x16x16, with an open top. Line it with the wallboard of your choice: plain old sheetrock, or greenboard. Use Kerdi membrane and follow directions, and thinset a lining of Kerdi to the box inside. Fill it up with water, and look at it weekly to keep it topped up. Report back to me in a few months. Tell me how skanky the water is looking, but I bet your board will still be dry.
I've got it in my tile showers. For sure.
Schluter has a wealth of info at their site, including installation videos. The one showing a complete shower going together, from the floor up, is very good.
If you don't like new technology (remember that asphalt roofing shingles are a reasonably new technology in shedding water off roofs), then listen up. The membrane in a conventional mud shower base is placed atop the drain-pitched first mud layer, and it seals atop the mud flange of the drain fitting. The second layer of mud, also pitched for drain, goes on top of the membrane. If you saw through a properly made shower base, you will see a concrete sandwich with the membrane in the middle, sloped to the drain at the center. Use CPVC, not PVC.
It is probably a good idea to lay down a thickness of builders felt on the ply or OSB subfloor before packing on the first mud layer. It will cure better than if laid directly on a substrate that might draw water from the mix prematurely.
Edited 4/30/2003 10:01:53 PM ET by Mr. Micro
Micro
Sorry....I meant to say Schluters but I'm used to saying Ditra cause its easier to say. I should have posted their site because they make all kinda great products. http://WWW.Schluter.com
I use the Ditra mostly cause I do more floors than showers but you're right...the proper product is their Kerdi.
I get in the habit of calling all similar things the same...like I call all reciprocating saws Saw Zalls and all power saws Skill Saws.
My apologies.
Be a person hanging head in shame
Namaste
andy
In his first interview since the stroke, Ram Dass, 66, spoke with great difficulty about how his brush with death has changed his ideas about aging, and how the recent loss of two old friends, Timothy Leary and Allen Ginsberg, has convinced him that now, more than ever, is the time to ``Be Here Now.''
http://CLIFFORDRENOVATIONS.COM
I love the beauty of the double mud job on the floor, but I have a suggestion that I have used in the interest of saving time (not much) but more importantly an extra trip for the tile man (who always seems scheduled to the max).
I will install the first subfloor of plywood (3/4" cdx) screwed and glued to the joists, then create my own slope with a series of starter course shingles laid and staple to the ply (a fan like pattern with the thin end approaching the drain). Then I will screw and glue a layer of 1/2" over the top, the 1/2" is flexible enough to pick up the pitch from the shingles and solid enough to span any small gaps in the pattern. Then the plumber does his thing with the membrane and we turn it over to the tileman. All trades seem happy, my guys even like creating the shingle tip pattern, and noone has to make a double trip.
We also precut the last layer of denshield (or durock) and install after the plumbers pan.
Bill
Bill,
All due respect.
I'd never use Denshield or Durorock on a shower floor in spite of what the claim is. My personal preference is a mud floor in a shower area. If in fact I were to use a CBU I'd only use Wonderboard. It's "much" more dense than Durorock. Pick up a sheet of each and feel the difference.
I spose its what the customer is willing to pay, isn't it? Or is it laziness on behalf of the builder? Thats a whole other question or thread.
Be a craftsman
NAmaste
andy
In his first interview since the stroke, Ram Dass, 66, spoke with great difficulty about how his brush with death has changed his ideas about aging, and how the recent loss of two old friends, Timothy Leary and Allen Ginsberg, has convinced him that now, more than ever, is the time to ``Be Here Now.''
http://CLIFFORDRENOVATIONS.COM
Andy,
Reading his post again, I think he's talking about the dens-shield that is going on the wall of the shower. He isn't clear about what is going above the membrane on the floor.
Rich Beckman
Another day, another tool.
Sorry my fault, when I said "turn it over to the tileman" I was implying (albeit only in my own mind) that the tile man would then pour, screed, lay, install a single layer of mud over my pre-sloped membrane. The point being, only one time in for the tile man and only one mix of mud on the job for the floor...my fault for being imprecise.
Bill