# What's wrong here.



## Mike Finley (Apr 28, 2004)

ron schenker said:


> Did a tiling job last week, 12x12 ceramic at the front entrance and 3 days later noticed some(sanded) grout around 1 tile was cracking. I removed the tile quite easily and found the adhesive I used was still tacky. Shouldn't it have been bone dry by then? Subfloor was 1/2" planks laid diagonally, and 3/8" plywood on top of that. After removing the sheet vinyl that was there originally, I screwed down the floor nice and solid, no crowns, no bounce. After my repair everything was o.k. but I'm wondering if the adhesive is dry yet. In retrospect, maybe I should have used thinset?:innocent:


Yes, use thinset...

...avoid bonding to wood. Wood expands and contracts right? Expansion is the killer of tile. Plywood is much better than dimensional lumber when in comes to bonding to wood, but there is still no reason to bond to plywood in my opinion. 1/4 Hardi Backer would have been my choice... thinset is cement based, Hardi Backer is cement based - see the pattern? :smile: 

3/8 plywood over dimensional lumber? I would have wanted to see 3/4 but that is neither here nor there.

I fear that the one tile you discovered won't be the last one you have to deal with. One coming off like that is surely the precursor to more down the road, you might want to get a tube of color matched chalk to have on hand to fill in the cracks in all the grout that is likely coming over the next few years.


----------



## Mike Finley (Apr 28, 2004)

Florcraft said:


> But it DOES work in alot of applications. There is a place for it in the industry.
> It wouldn't be around if it didn't.


By the way I'm having a brain fart, but what application requires mastic over thinset?


----------



## Tom R (Jun 1, 2004)

Mastic is more user-friendly, - - thinset is more idiot-proof.

Mastic has much better initial holding power, - - that's what I like about it. When the grout and caulk and other procedures are done correctly it will last for years and years to come. 

Problem is, SHODDY WORKMANSHIP, by both DIY'ers and contractors alike has caused the need for products that will make up for user-errors.

Beings I don't fall in that category, - - mastic always has and always will work for me, and for that matter, several tile-setters that I know of.

Although I do know of one who says he HAD to switch to thinset for walls, - - not because the mastic wasn't working for him, - - but because he was losing jobs to customers who were listening to the 'thinset-sales-pitch' by other contractors.

As far as flooring, - - plywood was used SUCCESSFULLY as a tile substrate for years and years before cement-board even existed. All the hype in the world can't/won't change that fact.

I WILL concede that both thinset and CBU are more idiot-proof, - - and probably SHOULD be used by most.


P.S. Not trying to convert anybody, - - just stating the 20-plus year FACTS as I KNOW them to be. 100 people saying otherwise can't change what already IS.


----------



## Tom R (Jun 1, 2004)

Mike Finley said:


> By the way I'm having a brain fart, but what application requires mastic over thinset?


REQUIRES is your word, not his, - - but of course you already know that.


----------



## justin savage (Apr 4, 2005)

Just because you have done something a certain way for 20-30 years doesnt mean you have done it right for 20- 30 years. justin


----------



## Tom R (Jun 1, 2004)

justin savage said:


> Just because you have done something a certain way for 20-30 years doesnt mean you have done it right for 20- 30 years. justin


Welp, - - let me say this about that, - - if I ever had even ONE failure, - - I might tend to agree with you. 

But in the meantime, - - just because YOU have done something a CERTAIN WAY for 'how-ever-many' (SOMEHOW I doubt 27) years, - - doesn't mean it's the ONLY WAY, - - although I see you would PREFER to believe that.


----------



## Tom R (Jun 1, 2004)

Just imagine the look on the customers faces when I show up to tile jobs that were done 20-some years ago, - - that are still holding up like the DAY ONE, - - and tell them I'm here to rip out that BAD TILE WORK I did in 1979, - - even though it APPEARS there's nothing wrong with it, - - because JUSTIN SAVAGE and a few others on this site I'm on told me I did it wrong!!  

Frikkin' HILARIOUS!! :cheesygri

Thank you for posting, though!!


----------



## Mike Finley (Apr 28, 2004)

Ron, I talked to a tiling pro out here in Denver about your problem and got some information for you. This guy has been setting tile forever and does the majority of his work for custom home builders on million dollar plus homes. His name happens to be Ron too. 

According to Ron what you are experiencing is the result of a lot of bad combinations of good products. Ron says the problem with mastic is it requires air to dry and takes a very long time to cure. He doesn't recommend using mastic on tile larger than 6"x6" and never uses mastic on a floor regardless of the tile size, because he says mastic under a 12"x12" tile will take up to 6 months to fully dry, grouting it extends the drying time even longer. On a wall he said you can get away with using mastic and larger tile since nobody is walking on it during the long drying time. He said you could get away with mastic on your floor if you used smaller tiles and didn't grout them for a week or two.

He said the mastic will eventually cure under your floor but it is going to take a long time and recommends not walking on it for at least a week.


----------



## Zero Punch (Nov 14, 2005)

First the sub floor is below minimum for ceramic installation 1 1/8 in. Second deflection has not been taken into consideration. Third mastic manufactures only garantee their product not the installation or the appropriate use of it. I quite using mastic when floor tile went over 8x8 and refuse to install larger tile without CBU and modified thinset the failure rate is too high. 
I still use mastic on greenboard walls and when properly installed have had no problems but more customers are informed and now want CBU and thinset. I have no problem and just charge accordingly. 
We all have opinions and prefered methods but I believe that there is a concensus that some methods enjoy a greater chance of sucess than others and that is the bottom line a successful installation results in a happy consumer.
My screen name is what I aspire to, so finding and using material and methods which eliminate callbacks and encourage referals is my main goal. This is not the be all and end all of online construction information, though I find it helpful, informative and enjoyable with pleasent members it is only one of many I frequent as time permits. I respect the owners and their providing this forum and do not post links to others I have at times refered others at other sites through PMs links to this site. :thumbsup: 

John


----------



## Nick H (Nov 13, 2005)

I'm with you Tom, over here I would say that 95% of wall tiles are fixed with what you call mastic but which we call readymix, certainly most DIY'ers wouldn't even know what thinset was. 
I've used readymix many many times and like Tom have never had a problem. The key is to only use it where it is appropriate such as on plastered surfaces or plasterboard, sometimes you may have to prime the surface but not always.
As far as fixing to plywood, i've used thinset with a flexible admix, primed the surface with the flexi , and the tiles will NEVER come of. This is a perfectly acceptable and widely used method to tile over timber floors, pipe casings, access panels etc, cement backer is used as well now but ply is by far the most popular material.
I would piont out that I get all my tiling supplies from a long established local supplier who also run there own team of tilers and I have ALWAYS followed there advice on installation and i've yet to have a failure.

Nick


----------



## ron schenker (Dec 11, 2005)

Wow, I seem to have opened a can of worms with my littlle thread here! Mike, you answered my question perfectly, thanks. I'll tell you one thing, I sure learned alot.:thumbsup:


----------



## R&D Tile (Apr 5, 2005)

Mastic should only be used for 8x8 tile on walls in dry areas only, it should NEVER be used on floors or larger tile and NEVER for stone of any size anywhere,:thumbsup:

There is no such thing as pre-mixed thinset, it's just mastic with sand in it, garbage and shouldn't be used for anything. 

Tiling over wood subflooring can be done, but certain measures have to be taken and not worth the chance, like 2 layers of sheet plywood to start and ceratin thinsets used, not going there now.:no: 

They make thinsets that hold tile from sagging better than mastic and is cheaper to use, mix it, the only good thing about Mastic is the size of the bucket it in comes in, empty it and use it to mix your thinset.


----------



## Mike Finley (Apr 28, 2004)

R&D Tile said:


> the only good thing about Mastic is the size of the bucket it in comes in, empty it and use it to mix your thinset,



  that made me laugh!


----------



## R&D Tile (Apr 5, 2005)




----------



## Bukemdano (Mar 12, 2005)

ccoffer said:


> Acclimation is a BS recommendation. Sounds like you bought a bucket of lousy mastic. I am not a fan of installing tile to plywood with anything at all, but if you choose to take that route, you had better be using an ultra-premium thinset.
> 
> Mastic is for dry walls. It ain't for floors. Mastic+traffic=failure.



Firm believer in "Acclimation"... However, if using plywood with glued layers, I cant picture it moving too much if at all. Someone know for sure?? Tom, what are you referring to when you mention "exterior" plywood? I have to say one thing about 1/4 hardi board, it is a LOT of work and LOT of screws. 4" spacing around peramiter of hardi board? I wonder if its just to get you buy more screws....


----------



## Mike Finley (Apr 28, 2004)

Tom R said:


> and for that matter, let the tile acclimate at least 24 hours.


Tom do you really let tile acclimate for 24 hours? I've never heard of that before. What is the tile doing during this acclimation period?


----------



## R&D Tile (Apr 5, 2005)

Bukemdano said:


> Firm believer in "Acclimation"... However, if using plywood with glued layers, I cant picture it moving too much if at all. Someone know for sure?? Tom, what are you referring to when you mention "exterior" plywood? I have to say one thing about 1/4 hardi board, it is a LOT of work and LOT of screws. 4" spacing around peramiter of hardi board? I wonder if its just to get you buy more screws....


You would still need that many screws in the plywood anyway, you can't tile over one layer on the joist, you need 2 and I still wouldn't do it and guarantee it, use the 1/4" CBU or a membrane over the plywood, the plywood needs to be Ext, grade AC or BC, NO CDX.

The joists system needs to meet specs for tile or stone as well.

Don't forget the unmodified thinset under all CBUs.

Anything else?


----------



## Tom R (Jun 1, 2004)

Mike Finley said:


> Tom do you really let tile acclimate for 24 hours? I've never heard of that before. What is the tile doing during this acclimation period?


I usually (special) order and pick up my tile well before I use it, - - it gets stored out in a building behind my shop, - - just don't seem right installing 10 degree tile in a 70 degree room. Crazy?? Maybe.


----------



## Tom R (Jun 1, 2004)

R&D Tile said:


> I'm sure when I return later, I'll be told I don't know a thing.:laughing:


You're too funny.

Actually, in case you didn't notice, - - no one is arguing your (or others doing the same) methods, - - it is YOU (and some others) claiming to KNOW IT ALL and putting OTHERS methods down.

If you're mind is set that mastic is useless, - - you are of course, entitled to that. 

If you can convince some others, - - you are entitled to that, too.

In the meantime, - - beings I'm one who's successfully 'using' it, - - and you're one who's use of it never seems to get past the 'sh!t-speak' level, - - you'll probably be better-served convincing someone else how bad of a product it is, - - that is, when and if your 'ranting' finally convinces yourself.

Oh well, - - gotta go and take a HOT, STEAMY SHOWER now, - - in my 1993 4 X 4 'MASTIC-TILED SHOWER/ON DRYWALL', - - but HEY, - - I'll be sure to let you KNOW if any of the tiles FALL OFF onto my 1993 8 X 8 'TILE-ON-PLYWOOD' floor!! :cheesygri 

READ IT AND WEEP!!


P.S. Oh yeah, - - forgot to mention the part about the 1993 'DIAGONAL-TILE-SHOWER-SOFFITT, - - yep, you guessed it, - - MASTIC ON DRYWALL!!

And bein's I'm such a DARE-DEVIL, - - I'll be taking said shower WITHOUT a HARD-HAT!! :laughing:


----------



## R&D Tile (Apr 5, 2005)

Sorry to have ruffled some feathers here.


----------

