# setting over fresh concrete



## bowtie (Feb 4, 2012)

I have a situation where a small recessed area has been floated with concrete, it needs a SL on top of it to match existing slab heights ..

The concrete is days old, with curing it may/will crack and of course the SL will crack with it ..

My question .. any thoughts on a particular SL for that situation? And, would using some form of a crack suppression membrane over that be sufficient to set on? Using 254.. 

Don't want to want 28 days obviously.


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## PrecisionFloors (Jan 24, 2006)

http://www.tcnatile.com/faqs/26-concrete-curing.html


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## GO Remodeling (Apr 5, 2005)

Ditra is a vapor equalization membrane. Pro flex. Maybe the new Laticrete membrane. But read the tcna tile over concrete article. It's good stuff to know.


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## bowtie (Feb 4, 2012)

Thanks .. although that didn't address any of my questions ..


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## bowtie (Feb 4, 2012)

olzo55 said:


> Ditra is a vapor equalization membrane. Pro flex. Maybe the new Laticrete membrane. But read the tcna tile over concrete article. It's good stuff to know.


Unfortunately I can't use ditra because of height issues, this is adjacent to existing tile, I'm not finding info on other vapor membranes ..

1300 sqft of wood look tile on a hammered floor, have about 200 more to finish, this has not been fun ..


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## ee3 (Feb 10, 2006)

Nobleseal !


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## ee3 (Feb 10, 2006)

Nobleseal ! Maybe with rapid set.


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## bowtie (Feb 4, 2012)

That will work as good as anything I believe, was leaning that way.

Gracias senor ..


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## MIKE ANTONETTI (Jul 17, 2012)

Tec has a thinset for 3 day old concrete. Not sure about membrane, I would think one that utilizes the fibers to lock in to slc prior to setting, you still will need a zig zag soft joint,


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## GO Remodeling (Apr 5, 2005)

Which Nobleseal? CIS or TS? To have vapor transmission properties in this case,wouldn't'there need to be an air space between the tile and the concrete? Nobleseal doesn't have that. Just using a crack isolation membrane would be the longer waiting period.


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## MIKE ANTONETTI (Jul 17, 2012)

There's also crack protection built into some thinsets like isolight by tec, but the green concrete may conflict, I would use single manufacturer system to see what they would recommend. Mapei makes full line of products,slc,membrane,thinset. But tec is the only one I know of for 3day old concrete.
Laticrete I would also check.
In this situation I would ask myself , What would Coffer do? And then not do that. Just playin.


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## ee3 (Feb 10, 2006)

TS or CIS .
The air space dose not have air flow,there is no air movement.The space may allow the moisture vapor just to go back to water. There is a committee formed tring to sort out what is what and write a standard for ANSI.


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## bowtie (Feb 4, 2012)

Laticrete 254 doesn't require a minimum cure time for concrete either. 

What I can't find is a self leveler that doesn't require a 28 day cure time ..


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## ee3 (Feb 10, 2006)

The 28 days is just a number that has little to do with anything except running test on the concrete or mortar itself.What ya need is the moisture reading of it..:whistling


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## GO Remodeling (Apr 5, 2005)

what moisture reading is acceptable? 

The waiting period, if I understand it correctly, is for the concrete to complete a shrinking process(TCNA). They comment that the drying varies based on multiple site conditions, the mix and placement methods.

EE3. While they might not be air movement, there is vapor movement from high pressure to low pressure. I understand your point about vapor hitting the plastic and possibly condensing. But Schluter doesn't market it that way, does it?

Back to Nobleseal. How would applying a CIS allow the vapor to equalize?


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## ee3 (Feb 10, 2006)

depending on the bonding agent the 12# pound range or 95%.
The 28 days is what you said , a time that you wait before you test .(slump,compression,shrinkage,ect.)Kinda like testing a 7 day shear with bonding agents,a point in time. 
It works through Magic ! Kinda like a bonded slip sheet or curing blanket.
Before Laticrete had Stratamat they used to use us on wet slabs bonded with 254 then set the tile.


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## MIKE ANTONETTI (Jul 17, 2012)

SLC from Mapei is 5lbs. Max. Or you would get possible crumbling effect.


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## Ethos (Feb 21, 2012)

olzo55 said:


> Ditra is a vapor equalization membrane. Pro flex. Maybe the new Laticrete membrane. But read the tcna tile over concrete article. It's good stuff to know.


My vote is for Ditra as well. It's designed not to translate cracks.


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