What is the smallest tile that can be installed over Strata Mat by Laticrete?

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Jadnashua

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FWIW, the reason there's a tile size minimum on this type of membrane is that the raised portion of the grid does not have mortar under it...IOW, it is a VOID. Tile hates voids (a bigger tile will be supported by enough columns of thinset to keep it from potentially tipping with a point load), and IMHO, the combination of multiple layers of thinset, mesh, etc. on top of the mat does not negate the fact that a small tile will end up over a void, and while a point load in a bathroom is unlikely to crack a tile, it is against all that the manufacturer calls for. Throw in a good sized lady in spike high heels, and your results may differ.

On these mats, any required leveling must be done BEFORE the mat is installed. Thinset mortar is not designed for floor leveling. Thinset mortar makes a great bond to tile when done right. Per the installation instructions (page 21) http://www.laticrete.com/Portals/0/datasheets/DS-010.5.pdf , all leveling must be performed BEFORE installation of the mat.

So, with the multiple diversions from the manufacturer's instructions, while this floor might last, all warranty would be in question...best to do it the way the manufacturer calls for. Is this John's idea of perfect?
 

Jadnashua

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When something is done that goes against the published manufacturer's instructions, without providing backup, most people would assume there are problems. Had you provided the exception to published instructions from the manufacturer as part of the education, it would have a lot more useful, and less confrontational. Most people seeing this, without that, would not know the details to make it work, and would be lead to an installation that would be much more likely to fail.
 

Jadnashua

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I've thought about this, and I think this thread does not belong in a DIY'er forum. IHMO, to achieve a good install with tile smaller than 2x2" over a mat like this requires more skill than a typical DIY'er and some pros to be able to get first, a consistent, level screed the proper depth over the top of the mat, and if it isn't, get the small format tile set so that they are acceptably flat. Yes, there are ways to do this, but most people won't take the time to accomplish it properly. Plus, many DIY'ers do not read, and when they do, they do not always understand the instructions or the ramifications. And, they may then make assumptions, and create a bad situation. The manufacturer's goal is a reliable installation for the target user. Both of the mats in question are marketed for DIY'er and pro...my vote, leave the exception to the pro.

Without the specific instructions from the manufacturer you posted...someone just skimming the thread or the title could easily be lead to an improper conclusion and not generate a reliable project.
 
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Jadnashua

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Again, John twists words.

Pick a product designed for the intended purpose, and install it per the manufacturer's instructions. Using recommendation from one company to apply to a similar product is a personal decision, and does not mean there are characteristics of the two materials that allow the same techniques to work.

I never said the floor shouldn't be level. I did say, and the manufacturers of both Ditra and StrataMat say to level the floor BEFORE installation of the membrane...John chose not to do that. He chose to not follow the instructions of the manufacturer on the tile size installation. He performed a screed layer of thinset that would be VERY difficult for a DIY'er to perform. Any tile is MUCH harder to get to lay flat when the substrate is not flat. Anyone who knows tile, they want a flat surface, level may or may not be required, but is often nice.

So, we have a situation that the material was not installed per the manufacturer's specs, leveled over it rather than before installation, and then a layer of setting materials applied over the top that is beyond the scope of the average DIY'er, and some pros. No discussion on the type of materials required to get the surface flat at the required depth...normal thinset should not be used - many thinsets cannot be installed as thick as were used here.

I stand by my recommendation, that this thread is not a good idea for a DIY'er forum...StrataMat is not designed for tiles smaller than 2x2, and the manufacturer will not warranty it when they are used. It may stand up well when installed in that manner with the technique described, but the average person will not be able to duplicate it. It does not belong in a DIY'er forum. The goal here, IMHO, is to guide people into both a method of installation that they can perform AND will meet all of the manufacturer's instructions to maintain their warranty.
 

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And, I'll repeat, the average person will not be able to replicate this install. ANd, John still doesn't understand my comment on the requirement for flat or level...tile wants a flat surface (and, while level isn't required for tile, it is nice for the room - things tend to fit better!)...the average person will have trouble doing that over StrataMat and keying it in properly to the pockets. The reason both Schluter and Laticrete say to level the floor before the installation of their mats is for that reason...it is much harder.

Throw all the darts you want...you are wrong, but do not want to admit it.
 

Jadnashua

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I used the 254 as a slurry coat and then dropped a dry mix of 3701 over top. Hit the 3701 with my magnesium float and with a four foot level inched my way from the back of the bathroom to the door.

The bathroom floor was way out. A hump near the vanity and a massive pitch to the door. I'd say the floor is out almost 3/4" over 4'.

FWIW, since you don't really bond anything to the Strata_Mat (yes, with the perforations, you do get a bit of bond to the substrate beneath), and there isn't all that much beneath the mat, it would seem that this installation with the 3701 on top would be closer to an unbounded mortar bed. Per the data sheet, when using 3701 in that manner, it needs to be a minimum of 2" thick with reinforcement mesh. At approximately an inch or so to compensate for the out of level and the minimum thickness to meet Schluter's (not Latticrete's) spec for use over a mat, it doesn't seem like this meets manufacture's specs. The other uses of this material are over a slab allow it to be thinner. Now, maybe this is on a slab. http://www.laticrete.com/Portals/0/datasheets/LDS1000.pdf But, with the known voids in the mat, is it really safe to treat it as a bonded mortar bed?

Again, this does not belong in a DIY'er forum.
 

Vegas_sparky

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I don't know why it shouldn't be in a DIY forum. Most of us don't have a clue about what we're doing, and end up going with something we're comfortable with. I'm a perfect example of that. Oh what a mess I've made. Best thing I have going is up sizing the drain to 2". That might give me a fighting chance at minimizing my epic fail! LOL
 

Jadnashua

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Let's recap what was done here in an effort to show how to use an unsupported tile size on Strata-Mat as an example of good technique on a DIY'er forum...
- Heating cable embedded in something (thinset?)
- More thinset and Strata-Mat
- 254 as a slurry coat – How does one ‘bond’ a mudbed to a decoupling layer?
- 3701 applied as if it were a bonded mudbed (not installed per the manufacturer’s instructions regarding depth or reinforcement)
- Another skim coat of 254 and a reinforcement mesh. This cracked…right product for the right purpose?
- More 254 and another layer of mesh
- Thinset and tile

So, at the end, we have multiple layers of materials, not installed per the manufacturer's instructions or any TCNA guidelines and tile installed that is out of size range as specified by the membrane manufacturer so no warrantee.

All this as an example of 'good workmanship' and DIY'er friendly install. I think not.
 

Jadnashua

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Tiling 101...prep and understand the situation before you throw lots of layer trying to patch a problem. There's a good reason why you level below the decoupling membrane. That you realized later that it was way out of level points to the first step of tiling 101 - prep properly.

There's a good reason to use a decoupling layer over floor heat - no matter what, the heating will be somewhat uneven...yes, it stabilizes pretty well, but during the on/off cycles until things stabilize, it is not even. This will cause the areas closer to the heat to expand and contract potentially more and faster than what is above. One reason why both Laticrete and Schluter tell you to level before installation of the membrane is that if done after, that layer will not be heating and cooling as evenly as if it were a single, monolithic layer. This means that much of the benefit of the decoupling layer is now lost- the top surface will not be expanding and contracting as a nice, even layer, even compared to what is below.

Trying to do a bonded mudbed technique over a decoupling layer is unlikely to work (and it did crack).

A poor example of how to do things...
 
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