# questions about thinset



## angus242 (May 1, 2008)

ponch37300 said:


> After searching threw several posts I'm a little confused about which thinset I should use where for my situation. The first is my floor, I have 1x8s and then I layed 5/8" ply over the top of them with an 1/8" gap at edges. Now I am going to be putting 1/4" hardi backer on them and should I use modified or unmodified thinset for this? And I use modified for setting the tiles right? Second is another area that I will have 2 layers of 3/4" plywodd and then plan on using ditra. I need to use modified thinset for setting the ditra right? And I'm putting marble tiles on top of this, what kind of thinset should I use for this? From what I have read ditra recomends unmodified thinset for anything on top of it? They make a special thinset for marble and granite from home depot that is modified, would it be a bad idea to use this for the marble? Thanks for any help, seems like the more threads I read the more conflicting info I get.



Hardibacker: modified under and over

Ditra over plywood: modified under, unmodified over. This is not a recommendation, it's a requirement.


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## JazMan (Feb 17, 2007)

Harbiebacker: Either mod or unmod under, modified to set tiles.

Ditra over plywood; Must use modified under, otherwise it won't bond to wood, Use a high quality unmodified to install your marble tiles. You won't find such a thing at HD though. Go to a real tile shop, find a thinset that is classified as meeting A118.1 specs and is a premium quality. Should cost around $10-15 per #50. Most marbles require white. What other brands can you find? Where in WI are you?

Jaz


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## ccarlisle (Jul 2, 2008)

For your marble tiles, it depends what kind of marble and what colour it is...some marbles absorb water, some don't. A white Carrera marble will absorb grey thinset and eventually show greyish clouds within the stone. So they make a white thinset just for this.

Conversely for a dark marble and white thinset...


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## ponch37300 (Nov 27, 2007)

Thanks for the answers everyone. 

Jazman, I am from appleton. I can get laticrete from Lowes, Mapei from Menards, and custom building products from home depot. I have read that Mapei and Laticrete are pretty good products, is this true? If they are is there a certain thinset that you would recommend? 

My marble is a blackish color so would I use a grey thinset then? All my tiles will be 12x12. What size trowel should I use for setting the hardi, setting ceramic on hardi, setting the ditra to plywood, and setting marble to the ditra? Thanks again for all the help.


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## JazMan (Feb 17, 2007)

They all make good products. The only thing I don't like about Custom is they don't make a premium unmodified anymore, just that cheap Custom Blend stuff. 

Look for the spec "A118.4 and or A118.11 for modified thinsets.

Unmodified thinset will meet "A118.1". Just stay away from the cheap $5-7 stuff. 

Modified:
Custom's like; VersaBond-VersaBond Flex-Flexbond
Mapei; UltraFlex, usually UltraFlex 2 in the one that is easy to find. 
Laticrete, At Lowes; SpectraSet-Multipurpose

Unmodified; over Ditra
Custom; They don't make one I could recommend.
Mapei; Kerabond with water is good stuff.
Laticrete; 317 or Mega Bond mixed with water.

You might also consider a real tile shop where the clerks might know what they're talking about....maybe? You might find Hydroment or Durabond? They are licensed by Schluter to produce Ditra Set, which is perfect for over Ditra. The parent company is Bostik and they have a plant in Wauwatosa, WI. Oh, wait, Ditra Set only comes in white. You should use gray with your dark marble tiles. 

OK, I forgot about the trowels. 1/4x1/4x1/4 for under Hardie. If the other tiles are ceramic a 1/4x3/8x1/4 should be the right one. Use a 5/16 V for Ditra, it may be hard to find, so I have cut bigger notches to a 3/16x1/4. The 1/4x1/4x1/4 should be good for the marble over Ditra since the tiles have flat backs. 

Have you determined that your subfloor system is adequate for this installation? Especially the marble.

Jaz


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## ponch37300 (Nov 27, 2007)

Thanks Jaz. That info is much appreciated.


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## JazMan (Feb 17, 2007)

You're welcome.:thumbsup: But how about my last question?

Jaz


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## angus242 (May 1, 2008)

I prefer Mapei: 
Kerabond + water = unmodified
Kerabond + Keralastic = modified

Jaz's last question is very important as well...

did you qualify your subfloor structure for a natural stone installation?


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## ponch37300 (Nov 27, 2007)

Jaz, sorry I either missed that last question or that's what you edited. The floor is ceramic tile and that is good for ceramic, 2x10 joists spaced 16" centers spanning 12 feet, then have 1x8's layed diagonal and then screwed down 5/8" ply. The marble is for a counter top. I am going to lay down 2 layers of 3/4" ply and then the ditra for them. Hopefully this is enough support for them. Any tips for this? Thanks


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## JazMan (Feb 17, 2007)

OK, the counter are fine for sure. How you finishing the edges? The floor OK too. The Hardie is for the floor right?:thumbsup:

Jaz


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## ponch37300 (Nov 27, 2007)

The hardi is for the floor and the ditra is for the counters. I am finishing the edges with wood trim. Hoping the trim will be tall enough. They didn't make any bullnose or trim tile for the marble that I picked out so wood was the next option. Do you have any other ideas?

On a side note I am doing a bathroom counter in ceramic tile and posted a week ago about how to attach the v trim tiles. Do I need somekind of backer on the sides to attach the tiles to? One guy on here said you just thinset the tiles to the edge of the plywood, didn't seem like that would be the best way but I don't know. Thanks


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## ccarlisle (Jul 2, 2008)

So, now it's _two_ layers of 3/4" plywood on the kitchen countertops? I thought you had only one layer plus ditra...so which is it?

If you're sticking with two layers of 3/4" plywood, plus ditra plus thinset plus a marble tile, then my recommendation for Schluter mouldings is probably out because your thickness is out of sight. 

I don't put marble in kitchens. There are better choices but if you are determined to keep them, then acquaint yourself with your local stone restorer - because you'll need him - and he'll love for helping put his kids through college. 

We charge at least $XXX to restore a kitchen countertop. :yes:

Or just live with the constant reminders of this post, the stains and etch marks - and nagging SO. :wink:


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## ponch37300 (Nov 27, 2007)

Ccar, as mentioned in the last post this is still in the planning stages. "So which is it"? It is neither yet since I have said this is only what I'm planning on doing. 

I know you are strongly against marble for counter tops but the local tile store said they do a bunch of them and never had any problems. And you were the only one who said not to do it. I appreciate your criticism but until someone else says this is the worst thing to do, like you seem to think that is my plan. I have read that marble is fragile and stains easy but have also read that if sealed right it can eliminate most stains. Thanks


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## ccarlisle (Jul 2, 2008)

Well then, OK. 

But I'll tell you something else you may not believe either:

(a) What most dealers call "Marble" may not be marble at all. 
(b) You'll _never_ stain a polished marble tile, and 
(c) No sealer made will prevent what many people call 'stains' on their marble tile...

Crazy, eh?:jester:


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## ponch37300 (Nov 27, 2007)

They didn't have Kerabond, the only unmodified they had was keraset for about 8 bucks a bag, it is a118.1. Will this work for the unmodified?

And they didn't have keralastic either but they did have keraply. Will that work for the modified? They did have keraflex 1,2, and 3 for modified. 
Thanks


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## juliegogel10 (Mar 16, 2011)

I have black marble with tan going through it...never done marble before .....what thinset would I use and grout????and would a expoxy sealer work for the stains?


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