# 12x18 porcelain tile



## sponge racing (Apr 12, 2008)

Hey guys im putting some 12x18 porcelain tile throughtout my bathroom and im using a 1/2 x 1/2 x 1/2 trowel. Using flexbond to install. Do you guys think I should hit the back of the tile with some mortar? If so do u trowel it on or just pancake it all over the back. Thanks never installed this big a tile before.


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## CarpenterRN (Dec 3, 2009)

I burn the backs of just about every tile I set. I use a 6" taping knife and spread a thin layer. If you goop it on, then you could have issues with thinset being too thick, especially if you are using a 1/2" trowel.

Out of curiosity, what is your substrate?


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## PrestigeR&D (Jan 6, 2010)

*well Sponge,,, your name??????*

Let me throw a question back at you ,,, how "UN" level is your floor? 
Answer: it's called the "deflection rate" ,,center depression- center hallow. floor level first, 

there are directions and specifications on the brand of thinest you have,,, that \of which I do not know,, I believe you are reaching the MAX limit by dbling up. or trying to perform a "Oreo" application. Who ever told you to do it this way,,, buy some good BOSE sound head phones. Floor "level" and "structurally sound" first and foremost,,then apply your tile- 1/2" is what is used for un- GAGED natural stone.. a natural slate is a prime example...,, :thumbsup:. or ,,, the other,, a floor in which the deflection rate is exceeds -/+.25 IMO, in another words,, 1/4,, fractionally of the trench marks of the trowel at it's lowest point being centered, differentially,, you need to level the floor-,, CTIOA , they may state differently,, but ,they have "selective" situations they stamp their approval on,,,,, older,,,wiser,,,, I care about my work,,, :thumbup:
Brian


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## sponge racing (Apr 12, 2008)

Thanks for the replys guys, They are going on the wall over 1/2 hardie in the shower then green board throughtout the non wet areas. The floor is done already. The walls are all new construction with 16 on center 2x6s. The flexbond bag says to use a 1/2 x 1/2 x 1/2 for 12x12 and bigger. Sponge is just a nickname that they throw at me.. Thanks


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## PrecisionFloors (Jan 24, 2006)

I backbutter everything 12s and up.


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## PrestigeR&D (Jan 6, 2010)

*Prec,,*

why?
B


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## Mike Finley (Apr 28, 2004)

sponge racing said:


> Hey guys im putting some 12x18 porcelain tile throughtout my bathroom and im using a 1/2 x 1/2 x 1/2 trowel. Using flexbond to install. Do you guys think I should hit the back of the tile with some mortar? If so do u trowel it on or just pancake it all over the back. Thanks never installed this big a tile before.


Back buttering porcelain is pretty common. You comb it just like you would appying the thinset to the wall or floor. :thumbsup:


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## PrestigeR&D (Jan 6, 2010)

*really,,,,*

Again,,,, what is the point in doing so,,,,,,


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## sponge racing (Apr 12, 2008)

mike so hit it with the groves on the trowel? or just skim the back, filling the voids in the back of the tile?


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## CarpenterRN (Dec 3, 2009)

sponge racing said:


> , They are going on the wall over 1/2 hardie in the shower


What method did you use to waterproof?


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## PrestigeR&D (Jan 6, 2010)

*Voids,,,,*

yea,,,
Thats what I am talking about,, do what you want,,, i give up:turned:


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## PrestigeR&D (Jan 6, 2010)

*substrate,,,*

good old Concrete board under thinest-floor,,,,"LEVEL":thumbsup: an ounce of prevention is worth a bucket in the hand:thumbsup:,, 
Brian


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## PrecisionFloors (Jan 24, 2006)

PrestigeR&D said:


> why?
> B


Coverage.


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## Mike Finley (Apr 28, 2004)

sponge racing said:


> mike so hit it with the groves on the trowel? or just skim the back, filling the voids in the back of the tile?


Either method is used.


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## PrecisionFloors (Jan 24, 2006)

Mike Finley said:


> Either method is used.


Agreed, depends on the situation, the tile, the flatness of the substrate, etc.


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## JazMan (Feb 16, 2007)

This thread has gotten confusing and contradictory. :whistling

I think you should apply thin set to substrate. Burn in with flat side of the 1/2" trowel, then apply more and gauge with notched side. Back-butter the tile, beat in moving the tile back-& forth and space. 

It sounded like someone suggested spreading with notched side on both the substrate and the backs of tiles.

Jaz


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## PrecisionFloors (Jan 24, 2006)

JazMan said:


> This thread has gotten confusing and contradictory. :whistling
> 
> I think you should apply thin set to substrate. Burn in with flat side of the 1/2" trowel, then apply more and gauge with notched side. Back-butter the tile, beat in moving the tile back-& forth and space.
> 
> ...


Gotcha. Yeah I only key in one side, not both. But sometimes I do burn in on the substrate and burn and key the tile. Or burn and key the substrate and burn in the tile.


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## angus242 (Oct 20, 2007)

PrecisionFloors said:


> Gotcha. Yeah I only key in one side, not both. But sometimes I do burn in on the substrate and burn and key the tile. Or burn and key the substrate and burn in the tile.


That says it all right there :notworthy


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## sponge racing (Apr 12, 2008)

Thanks guys so I will trowel the wall and put a thin skim coat on the back of the tile without troweling it. As far as waterproofing I was going to roll out some black felt or use a plastic sheathing overlapping the tub lip but my thoughts were why bother if you caulk around the bottom of the tub not letting the water back into the tub. So it would just sit at the bottom inbetween the lip and the felt. Just my thought!!


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## angus242 (Oct 20, 2007)

sponge racing said:


> Thanks guys so I will trowel the wall and put a thin skim coat on the back of the tile without troweling it. As far as waterproofing I was going to roll out some black felt or use a plastic sheathing overlapping the tub lip but my thoughts were why bother if you caulk around the bottom of the tub not letting the water back into the tub. So it would just sit at the bottom inbetween the lip and the felt. Just my thought!!


Oh boy. Tile & grout are not waterproof. You will get moisture behind them. How do you deal with that??????


Take a look at this post to get a _small _idea of what you should be doing:
http://www.contractortalk.com/f74/tub-tile-backing-78312/#post936285


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## jarvis design (May 6, 2008)

Whats with the hardi over drywall?? Did someone tell you hardi was waterproof?:shifty:


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## sponge racing (Apr 12, 2008)

Hmmm ? if I did put the plastic sheeting behind the backerboard and caulk the bottom around the tub how would the water get back into the tub. Guess ill check out redguard that would be better then putting the tiles without any waterproofing. Thanks to all


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