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raiders510
07-24-2008, 09:14 PM
Hey guys. Long time watcher, first time poster.

I have been installing tile for over 2 years now as an apprentice. I bagged a condo renovation project and just about completed the first phase. I have been removing the old subfloors and installing new subfloors. I used to be in home renovations and I have laid many subfloors, but never tiled over them until recently. So with that said, let me describe my problem..

I was walking through about 10-15 units to make sure my installations were still holding up as they should be, when I noticed a couple of units with grout cracking in exactly the same place in a couple of different units in the front entrance. I was quite bewildered as I have not seen any problem like this in any of my installations before. The front entrances are about 37 inches wide, and slightly less than 10 feet long. As soon as you walk in the entrance, the tile begins and there is stairs going up at the end. I sorta scratched my head and tried to think of a cause where I could only come up with one explanation...

The grout is cracked in the 4th and 8th rows of tile (12x12 tile, and there are 10 rows of tile from the stairs to the doorway. The 10th row of tile is approximately a 10 inch cut piece) stretching the width of the entrance way in each unit. Well, I ripped the plywood at its width (48 inches) to stretch the width of the entrance (approx. 37 inches). Most of you tile pros know that a 12x12 tile is actually slightly smaller in most cases to allow for the grout joint of 1/8-1/4 of an inch. I started the subfloor at the stairs and ran it 48 inches toward the doorway, then began the next piece and ran that piece 48 inches toward the doorway and then laid a final piece of approximately 22 inches. I realized that the areas where the grout was cracking is where the plywood sheets "butt" together. I say "butt" because I left a small space to allow for expansion and contraction like I always have. So the grout joint is right above where the plywood sheets meet. I tiled many of these in the dead of winter in -30 to -40 degrees celcius. As most of you pros might know, its kinda hard to keep all your tools in a 10 foot long by 3 foot wide hallway so I kept them outside with the door open to allow for natural light (No lights were installed) while I was tiling and then grouting; Making my way from the stairs out the door. There is also a floor heater on the wall. I am hoping that thermal expansion/contraction due to the cold air mixing with the warm air from the heater caused the grout to crack during the winter. So I am hoping to hell that I am only going to have to scrape it out and re-grout rather. But it could also be that there are deflection problems or my subfloor install was not proper. Let me describe everything I know...

I laid 3/8" EGP over K3 which is of course over 3/4" plywood in the entrances. The reno company didn't want to pay me to rip out the K3 (With the lino scraped and removed from the top) in the front entrances because they figured it would be a waste of money when I could just go over top of it. The front door frame is elevated approximately an inch from the top of the existing K3 subfloor so leaving the K3 down and putting plywood over the top would not compromise the total height of the finished floor. I PL400'd and screwed the plywood down with 2 inch floor screws at 4-5 inches around the edges and 6-7 inches throughout the inside. Heres a possible problem is that without ripping out the K3 it's impossible to find the joists. Even with the K3 removed its still not a definite possibility that I would find the joists without possibly having to cut out a section of each floor. I had to cut out a section of floor in one of the bathrooms because it was rotted and I can't remember if they are 2x8 or 2x10 joists. I would say I am about 90% sure they were 2x10. They are spaced 16 inches on center and I am not sure about the span.

I scraped the grout out of these spots yesterday and replaced with fresh new grout, so we will see if it holds up. I am hoping this is the simple solution because ripping out a couple floors on my own dime doesn't sound too appealing....So does anybody have any ideas?

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scuttlebuttrp
07-24-2008, 10:02 PM
What is K3?
If that means Luan there's your first problem.
Your second problem is measuring stuff in celsius. :) Maybe you could translate -40 celsius to farenheight? :D
Anyways, what was the temp in the area when you tiled and grouted? If it was under 50 farenheight, there's another problem.
You need to ask the contractor about the joists. You need to make sure deflection is o.k.

cx
07-24-2008, 10:28 PM
Welcome, raiders510. First thing we need you to do is pewt a first name in a permanent signature line for us. :)

I'll move this over to the Professionals' Hangout where we prefer to deal more technically with problems and also because the pros are more inclined to be frank there. It's still a public forum, and everyone is still required to be civil and polite, but the guys will frequently be a bit more direct when they know we're all dealing from more the same expected level of knowledge and training.

Some clarification first.

Like Royce, I have no eye-dee what K3 might be.

Are we to presume that you set your tiles directly to this layer of 3/8ths plywood you added?I ripped the plywood at its width (48 inches)You say you ripped the sheets but I get the impression that you actually cross-cut them into pieces 37 inches long. That correct, or am I reading it wrong?

You indicate there is a 3/4" subfloor over the joists. Do you know in which direction the joists run? I'm interested in knowing if your 3/8ths plywood is oriented with the face grain perpendicular to the joists or parallel. Do we know the joist spacing?

Can you determine if these condos were built to code within the past, say, 20 years. Pertains to Royce's question about your joist structure.

Royce's questions about temperature could be significant, too. Well, except the one about converting 40F to C, but he knows that, too. :rolleyes:

Don't think it's gonna matter but you might wanna tell us exactly what thinset and grout you used.

My opinion; worth price charged.

scuttlebuttrp
07-24-2008, 10:50 PM
Did a search.
K3 is subfloor.
Does not belong under tile.
Like CX axed. What kind of backerboard did you put on top of the new ply?

matman
07-24-2008, 10:56 PM
What Royce and CX said about the temp and floor construction. I think if it were to cold during the install the thinset and grout would both fail. If they're all cracking over the ply seams there's probably movement there. You did say you used PL400. A heavy bead of PL4000 near the seams could cause that to happen. The ply could pivot on the bead of adhesive.

cx
07-25-2008, 12:33 AM
K3 is subfloor.
Does not belong under tile.Mmmmm, Royce? Subfloor alla time gotta be under tile. Very bad industry practice to have subfloor over tile, eh? No happy customers for you. :D

I can find reference to it being anything from a particleboard underlayment to an insulation for underfloor application. I still dunno what it is, but if they had vinyl stuck to it, I'm bettin' I don't want it in my subflooring for a tile installation.

I'll wait for our new visitor to 'splain us what his K3 is, eh? :)

valid point on the adhesive, Matt. 'Specially in sub-zero weather. Hell, onliest way I can see gettin' that stuff out of a tube at those temperatures is with a chain saw. Tough to get a full spread that way, eh? :twitch:

My opinion; worth price charged.

custombuilt
07-25-2008, 03:17 PM
it sounds like the tile was laid directly over the plywood.....correct?? I see that kind of install fail on the seams all the time--no matter how well the plywood was screwed down, their is internal movement in wood as well as expansion/contraction with temperature change.

raiders510
07-25-2008, 06:27 PM
Hey fellas. CX, I went and put my name in my signature right after I posted this thread. I have been reading this forum for a while and have noticed that everybody likes a first name basis right here which is great. Thanks for welcoming me and I'm sorry I posted in the wrong thread. Thanks for moving it....Well let me answer your questions...

Actually -40 celsius is equivalent to -40 farenheit. It gets pretty cold in Canada from time to time, and I'll be damned if I let a little cold stop me from getting a bit of tilesetting done. After all, it is how I pay for this roof over my head and my full stomach. I am well aware of the working temperature of all types of thin-sets and grouts. ANSI standards are somewhat different from the "Tile Bible" we use in Canada..And no I'm not talking about JB's books LOL. We use the TTMAC (Terrazzo, Tile, and Marble Association of Canada) which isnt too far off par from the American standards. It only took me approximately 30 minute to tile the entryways and then the door was closed and let to heat the room back up again.

I used Mapei Ultraflex 2, and Mapei Keracolor sanded grout; Bone in color. In canada, it is pretty much standard practice for tilesetters to adhere the tiles straight to the plywood. The cost of backerboards is too high for any home-builder to want to pay for, or any renovation contractor to pay a sub-contractor. You are looking at maybe 35 dollars (In canada) for each sheet, plus an additional 30 or so in labour to lay each sheet. Add that to 60 dollars for a 3/8" plywood subfloor supply and install, and you're looking at over 120 dollars just to put one sheet of subfloor down. I would love it if it worked that way all the time, it's extra money in my pocket. Of course, I always explain all possible options to each customer and the possible reprocussions of doing their tile installation to minimum code, and most just want a cheap old plywood underlayment. Hell I do multi-million dollar homes all the time and they want their 18x18 slate/travertine/marble just adhered to plywood. I always do a burn coat first, and then comb it out, and then do a butter coat on the back of each tile before they are laid. It's the absolute best I can do to assure a 100% bond to the substrate. Here they are still using green aqua board in shower stalls in brand new homes. Believe or not, even in multi-million dollar homes you see it. I've gone into places where the drywallers have installed Denshield with drywall screws and taped the seams with regular old drywall mud. It seems nobody cares. I think I am getting off-topic here but you are the only people on the planet that can relate to what I am saying here....

K3 is particle board that they use to install linoleum under. I figured it wouldnt hurt to leave the K3 under the plywood to add some strength, after all the buildings are about 30 years old already.

Matt, good point about the PL beads being a little too fat. Unfortunately, they were nice thin beads because I find if you put them down too fat, the wood doesnt go completely flat and you make a mess with that crap coming up through the seams.

Last but not least, CX, I always lay my plywood subfloors with the grain perpendicular (at 90 degree angles) to the joists. I know for an absolute fact that the joists run north-south in the upper floor, and so I assumed that it would be running the same direction on the lower floor. But then again, assuming makes an ass outta u and me. lol.....Yes what I meant about cutting the plywood at its width, I ran the grain going east-west through the hallway. So, the first seam would run 48 inches away from the stairs. Know what I mean?

stairs
________________
l-----------------l
l-----------------l
l-----------------l
l<---37 inches--> l
l-----------------l
l-----------------l
l-----------------l
l-----------------l
l-----------------l
l-----------------l
l_______________l
seam

cx
07-25-2008, 07:42 PM
In canada, it is pretty much standard practice for tilesetters to adhere the tiles straight to the plywood.There is a published method for tiling directly to plywood in our standards as well, John, but the requirements for the subflooring preparation are very strict in the type, number, and thickness of the plywood layers required. Your 3/8ths plywood over a thin particleboard layer over a 3/4" plywood layer would certainly not qualify.

I have not got a copy of y'all's TTMAC publication, but I would be hard pressed to believe the method you've used there would comply with the methods listed there.

Bonding the tiles to the plywood is by far the least of your worries in that application. We've got thinset mortars today that will stick to a mirror. That's not the problem. The problem is the movement of the substrate you've attached your tiles to in relation to your tiles. Your current installations you've described there just don't have much of a chance of success, as you are seeing.

I still see no indication of joist spacing. That's another very critical item in the stability of the subflooring. Also, your trying to screw your very minimum layer of plywood into the joists through the existing subflooring layers is another negative to your installation as has been demonstrated by testing here in the states. You always want the second layer fastened only to the first layer, and not to the joists. This is most important when tiling directly to plywood, even when the plywood layers are of the correct thickness and otherwise correctly installed.

Pretty risky business that tiling to plywood, but we have some folks who do it successfully on a regular basis. But I'll wager that even they would be somewhat aghast at your installation method on that job. :)

My opinion; worth price charged.

raiders510
07-25-2008, 08:06 PM
Thanks for the info CX. You learn new things everyday. I haven't been tiling for all that long, and like I said I have never laid a plywood floor overtop of another layer of flooring besides plywood. Any input about how I should approach the situation? I have dug out the grout and re-grouted. Nobody is living in the units yet, but I imagine if it has cracked already, it will probably crack again with enough traffic. Should I wait for a customer to move in and complain? This might sound stupid, but is it possible to dig the grout out and run a bead of silicone and grout over top of that?

tilelayer
07-25-2008, 08:16 PM
i know a tile setter from nova scocia and he told me up in canada they are always tiling on top of plywood and doing jersey mud jobs he told me up there they never used cbu. I know theres some canadian tile setters on this forum. He himself is a good mechanic does mud and all that stuff but he told me the compitition was a joke up in those woods. I am not takin a shot at you raider fan.


I live in a condo myself and i tiled my upstairs bath i did it on drypack over 5/8s subfloor and its solid as a rock. I also made me mud about 1 1/4" thick and made it rock solid. I wouldnt have done it any other way. I also reinforced the floor before i did it. Who ever tiled it before did a "Jersey mud job" it was a joke to rip out. i wouldnt want to cbu condos due to the engineering i was lucky to have floor joists 16" on center.


also John you probably would have been better using thinset like Kerabond mixed with the latex addive instead of water it would make one sticky thinset. Im not to familiar with Mapei products and i know Ultraflex 2 is a good thinset but i used Kerabond and it had the additive it was so sticky.

raiders510
07-25-2008, 08:24 PM
Great thanks for your input. Yes there are a lot of installers who, myself as a rookie, see as a joke. No offence to anyone out there of foreign dissent (I'm German myself) but these guys come into our country and take up flooring invading the industry like locusts.

Anyways, CX, I've just checked with my TTMAC and the CSA-0121 states my compelte subfloor assembly must be at least 16mm or 5/8. I am over an inch with my complete assembly in the bathroom floors in the upper floor, and if you include the 1/2" particle board in the entry ways I am over 1.5". It also states that particle board is not acceptable in a subfloor assembly that is to receive a tile installation. So I suppose that begs the question, am I at fault as the installer, or is the renovation company and flooring company at fault for telling me to leave it in and continue my subfloor assembly and tile over top of it?

cx
07-25-2008, 09:59 PM
I suggest you read that book more carefully, John. I simply cannot imagine they would permit you to set tile over a single layer of 5/8ths plywood. I think your missing something there. Missing a lot, actually.

The particle board doesn't count at all on accounta it's not s'posta be there at all. It's a net negative.So I suppose that begs the question, am I at fault as the installer, or is the renovation company and flooring company at fault for telling me to leave it in and continue my subfloor assembly and tile over top of it?If you plan to stay in this business as an independent contractor, John, you're gonna need to get accustomed to being the expert when it comes to the matter of tile installation. Because that's what the court is gonna call you if you get that far in your first lawsuit for an installation failure. The "renovation and flooring company" may bear the burden if you are their employee, but if you're subcontracted to them they are the ones most likely to be on the other side of the table at trial.

You are expected to know how to make a proper installation according to contemporary industry standards. If your customer (the renovation company in this case?) invites you to do an installation incorrectly, they are within their rights to expect you to tell them it's incorrect. If you proceed with the installation anyway, and it fails, they can blame you as the expert of record. You would be within good legal grounds to toss it right back at them, calling them informed customers, but will you still be able to afford to be in bidness by then.

You wanna always be on firm ground in your procedures if you want to get to be an old timer in the industry. The more you adhere to industry standards and good operating practices, the less likely you are to have failures and the more likely to make money and stay in business.

One other good resource for you, one more in tune with the industry standards and practices up there in the Frozen North is our very good friend Harry Dunbar at Ontario Tile (http://www.ontariotile.com/). Harry's site has some forums similar to ours (not nearly as good, of course, but he tries :D ) and I'm sure you'll get much useful information there, too. Do tell Harry we sent you. :)

My opinion; worth price charged.

stullis
07-25-2008, 11:13 PM
Well I think you got some great info from the guys here about installing 3/8" plywood.

1) Acclimate your underlayment.
2) Quit using glue underneath your underlayment.
3) You need to fasten through the particle board into the plywood subfloor
but NOT into the joists.
4) A product such as ditra should be cheaper to supply and install than a
quality 3/8" underlayment, 3/8" plywood is NOT a quality underlayment.
It will take you longer to install the tile on ditra than plywood though.
5) A waiver release form would be a good idea when installing using less than
desirable methods but doesn't always hold up in court.

Now, what are you going to do about the existing problems?

If the tile haven't cracked and it is just the grout joints that are cracked you may want to dig out the grout and regrout with a more elastomeric grout and then cross your fingers.

Good luck,

raiders510
07-26-2008, 11:09 AM
Any suggestions for a good elastomeric grout?^

CX thank you for your wonderful input. I can see that you are obviously one of the very top dogs around here. My family has well over 100 years of flooring between my father, uncles, and my grandfather. I am the first breed of tilesetter so far, and I obviously plan to stick to what I have done. If I have to rip out 2 small floors, so be it. I will have definitely learned my lesson. And actually I am not an official sub-contractor at this point, I suppose I would be labelled officially as a Proprietor?

And when I said the "renovation and flooring company" I meant them individually at the company who owns the buildings that is doing the renovating, and the flooring contractor whom I am doing the work for.

Crestone Tile
07-26-2008, 11:52 AM
I don't know if I necessarily agree with not using an adhesive under the plywood underlayment. I might be wrong, but I think ANSI requires adhesive with fasteners when EGP is used as a tiling substrate. I can't remember if it is different for residential and commercial.

Nor would I advocate leaving the particle board sandwiched between the underlayment and subfloor. Maybe it would work out, but it's definitely not a specified subfloor construction for tile. ...and, I think that stuff is evil. :bow:

cx
07-26-2008, 02:31 PM
Indeed there is a place in the ANSI specs for installation of ceramic tile where it says a fella can secure, for residential use, 15/32 inch plywood underlayment "with adhesive and with 4d ring shank nails....." amongst other criteria. No other acceptable fasteners are indicated, nor any additional information on the required type nor method of application for the "adhesive."

Being a long-time ardent supporter of gluing all components of subfloors for any finish floor covering, I'd applaud that as a requirement if it were a bit more specific, as ANSI requirements usually are.

However, in the case in question in this thread, the gluing by the use of a gun-applied bead of construction adhesive is what's really being argued against. Especially in cold weather, a thick-bodied adhesive such as PL-400, applied in beads can create voids in panel to panel type applications. With the top panel being as thin as nominal 3/8ths plywood, I believe that alone can allow vertical movement sufficient to result in tile installation failure.

Gluing subflooring panels with full-spread glue and attaching with mechanical fasteners? I'm all in favor.

Gluing subflooring panels with beads of construction adhesive? I'm not in favor.

Having one panel be particle board? I'm not in favor.

Having any panel be as thin as today's nominal 3/8ths inch? I'm not in favor.

Some materials manufacturers do recommend the use of these thin plywood layers under their tiling substrates, though, and likely have test data to support their recommendations.

For a direct-to-plywood tiling application I think it wholly inadequate, but, then, I don't think it wise to tile directly to plywood even under the ANSI specified conditions. Just a personal opinion, that.

And I would like to see ANSI at least clarify the adhesive and 4d ring-shank nail requirement in their EGP/Portland cement requirements.

I'm also very much in favor of folks paying attention to the details of the ANSI standards as Matt (Crestone Tile) obviously does. Makes for good argument. :)

Not that I'm in favor of good argument, mind ya. :D

My opinion; worth price charged.

raiders510
07-26-2008, 03:56 PM
CX, I just re-read the last few posts and I realized that I typed the "complete" subfloor assembly must be at least 5/8" thickness. I meant that the first layer of subfloor must be at least 5/8 thickness. If I remember correctly, the complete assembly must be at least 1 and 1/4 inches...Not 100% though. One layer of 5/8" and another layer of 5/8" on top of that is 1 and 1/4". The flooring in this particular building is 7/8" plywood, so 3/8 and 7/8" is 1 and 1/4" if my math is correct. Although, cant you use Ditra over a 5/8 plywood subfloor? I thought I read that somewhere, not sure though, never used Ditra...Is there another way I should approach laying the subfloors in the next phase? You said to use a CBU or possibly Ditra. Would I need to install a second layer of plywood and then use the CBU/uncoupling method, or just go straight over the first layer of subfloor? Keep in mind, the building is over 30 years old..Then again, I'm not sure that even if I could convince them (The renovation company) that it would make for a much better and more reliable installation they would go for it because of the extra cost. After all, they didnt even want to pay me to rip out the extra particle board in the front entrances...

I'm still not completely convinced that the adhesive contributed to a possible installation failure, but I won't rule it out. It probably has a lot more to do with leaving the particle board underneath the plywood. When I told my grandfather I was using PL400, he immediately told me to switch to carpenter's glue and spread it all over the floor with one of those linoleum trowels. How do you feel about approaching the installation in this manner, CX? I'm refusing to say that all of my installations have failed because it has been almost 8 months and I only see grout cracking in 2 places. I have replaced the cracked grout with new grout and will keep everybody posted with how it turns out.

[edit]

I see you said "today's nominal width of 3/8". Thats exactly why I used 3/8 width. In conjunction with the 7/8 plywood subflooring, 3/8 brings me to exactly the height I believe I need. 3/8" plywood is basically all we use up here especially in new homes. (It matches the height of most hardwood and carpet perfectly. I have never used anything but 3/8. How would I go about using a CBU on top of plywood with tile on top of that? The height would be about a half inch higher than the carpet/hardwood at the transitions). Although, in new homes it is usually glued and stapled. I thought I would step it up and use floor screws and glue. After all, we know screws beat the hell out of any staple/nail installation all day, everyday.

cx
07-26-2008, 04:33 PM
CX thank you for your wonderful input. I can see that you are obviously one of the very top dogs around here.All dogs are at the same level here in the Hangout, JW. Everybody gets one vote. :)

I think you may be missing some of the more important points here.I meant that the first layer of subfloor must be at least 5/8 thickness. If I remember correctly, the complete assembly must be at least 1 and 1/4 inches...Not 100% though. One layer of 5/8" and another layer of 5/8" on top of that is 1 and 1/4". The flooring in this particular building is 7/8" plywood, so 3/8 and 7/8" is 1 and 1/4" if my math is correct.If that's what your standards say, so be it. But I doubt if your standards allow you to slip a sheet of particle board into that package and still call it within spec.Although, cant you use Ditra over a 5/8 plywood subfloor? I thought I read that somewhere, not sure though, never used Ditra.Yes, if you have 16" maximum joist spacing, but that is a manufacturer's specification and that specification is shared by a number of tiling substrate manufacturers. Much as I like Ditra, there's no way I would install it that way for a customer.

You must also keep in mind that all the manufacturer's specs are based upon new materials, in near-perfect condition, and with near-perfect installation. In remodel work you can never ensure any of those conditions.I'm not sure that even if I could convince them (The renovation company) that it would make for a much better and more reliable installation they would go for it because of the extra cost. After all, they didnt even want to pay me to rip out the extra particle board in the front entrances...This is one of those times you gotta decide what your personal standards will be and for whom you'll work and for whom you won't.I see you said "today's nominal width of 3/8". Thats exactly why I used 3/8 width. In conjunction with the 7/8 plywood subflooring, 3/8 brings me to exactly the height I believe I need. 3/8" plywood is basically all we use up here especially in new homes.I spoke of nominal thickness, not width. I don't know that I could purchase a sheet of structural grade plywood that was a full 3/8ths or half-inch thick in this country if I tried. Don't know that anyone makes it any more. Most all the plywood of that type we get here are marked as something smaller, usually 11/32nds for nominal (in name only) 3/8ths ply, for example. If you put a micrometer on some on a dry day, you're hard-pressed to prove it's thicker than 5/16ths in some cases. Really, really thin stuff and nearly impossible to screw down flat absent a screw gun attached to a steam roller. :rolleyes:

Maybe up there you still have full-size sheets? I can remember when they existed, but I'm a good bit older than some of the members here. :)

Waaaay younger than John Bridge and Flatfloor, though. :D

My opinion; worth price charged.

raiders510
07-26-2008, 05:24 PM
"If that's what your standards say, so be it. But I doubt if your standards allow you to slip a sheet of particle board into that package and still call it within spec."

Yea, absolutely agreed, I have already stated that the particle board was unacceptable.



"This is one of those times you gotta decide what your personal standards will be and for whom you'll work and for whom you won't."

Well, I want to try and do things to the best of my ability. I was just asking for your personal opinion (or anybody else's for that matter since it is a public forum) as a much, much more experienced setter. That's all...



"I spoke of nominal thickness, not width. I don't know that I could purchase a sheet of structural grade plywood that was a full 3/8ths or half-inch thick in this country if I tried. Don't know that anyone makes it any more. Most all the plywood of that type we get here are marked as something smaller, usually 11/32nds for nominal (in name only) 3/8ths ply, for example. If you put a micrometer on some on a dry day, you're hard-pressed to prove it's thicker than 5/16ths in some cases. Really, really thin stuff and nearly impossible to screw down flat absent a screw gun attached to a steam roller.
"

Yea, thats a typo, I meant thickness. My bad. Canada makes plywood in thickness from 1/4" to 1 inch that I know of.

stullis
07-26-2008, 07:14 PM
The grout used for snapstone tile or duraceramic would work. Several of the grout manufacturers have products that would work, don't recall the namees right off hand but you should be able to find them.

Jury seems to be out on StarQuartz.

cx
07-26-2008, 07:36 PM
Jury seems to be out on StarQuartz.Yep, yep, still out. But the deliberations have at least begun. I just grouted my first test board two days ago and am fixin' to start a thread with my thoughts, Scott. :shades:

I knew you'd be excited. :D

stullis
07-27-2008, 01:59 AM
I'm quivering in anticipation. :D :rofl:

tileguytodd
07-27-2008, 06:19 AM
I think perhaps ya'll are overthinking this........We have a couple small area's.....A Good Idea would simply be to fix them with a product like ....oh say C-Cures Uniflex

Regrout and call it done done & done...

I used Mapei Ultraflex 2, and Mapei Keracolor sanded grout; Bone in color. In canada, it is pretty much standard practice for tilesetters to adhere the tiles straight to the plywood.
In the future young man, if you are going to set directly to Plywood and you prefer Mapei products, DO NOT use Ultraflex 2..........Had you called Mapei for a reccomendation they would have told you to use Kerabond Mixed with Keralastic ( although I am NOT going to tell you to set on Plywood as I think its a damn fool thing to do EVEN using Keralastic)

raiders510
07-27-2008, 12:17 PM
^Thanks for the info Todd. I read the bag and it says I can use it on plywood, but I understand where you are coming from. Somebody earlier in the thread suggested that also. I checked the website, it doesn't look like there are any C-Cure carriers in Canada. I have never heard of that brand but I will ask around. You are suggesting ripping out the few tiles and then using a more flexible thin-set mortar and then re-grouting right?

cx
07-27-2008, 01:17 PM
Hottest thinset on the market ain't gonna prevent cracking at those plywood joints he has now. Nope, ain't a thinset problem. :shades:

My opinion; worth price charged.

stullis
07-27-2008, 02:11 PM
Actually TEC 1Flex setting material and their XT grout could be used according to TEC on a single floor system. ;)

IF I was going to set directly to plywood that would be the way I would go. :shades: