# Self Leveling Cement Concrete - (SLC) ... not pouring level



## DGEC (Sep 24, 2017)

I recently poured some SLC in 4 separate 2' x 8' sections that will eventually have tile as the finished flooring. Being that it is an old house the sections were out about an 1"+ from side to side. I poured the level quick and covered each section completely. After they cured I put a level down to find out that they were not level. 

I am confused because I was under the impression that the SLC should automatically find level like water. I am trying to figure out what happened and why the sections of SLC didn't turn out level. Has anybody else ever had this problem? I have one more section to pour and I am hoping to correct this problem.

Also as far as the sections go that I already poured... I am trying to correct them and make them level. Can I pour another layer of SLC on top of the already cured un-level sections of SLC? If so are there any steps i need to take like using primer or scratching the surface first?

Thanks!


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## avenge (Sep 25, 2008)

I would say you mixed it too thick and didn't help it along, need to check with the manufacturer on a 2nd layer. There might a time limit that you can add a 2nd layer without priming.


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## Golden view (Feb 16, 2012)

slc is not that easy to do, despite the name. Some people miss the priming step, which can help slow down the cure so it can level more. It also, as mentioned, needs some helping along. And unlike concrete, a thicker mix is not better.


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## Xtrememtnbiker (Jun 9, 2013)

Mix to the consistency specified on the bag. It will be fairly thin. Pour it out an use a metal garden rake with the tines down to help it move out in a hurry.

Disclaimer, I haven't done a lot of SLC, but this method works...


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## tjbnwi (Feb 24, 2009)

Travis is right about the rake, bow rake tines down assuming no heat cables.

Tom


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## dmcarnes (Dec 13, 2015)

You can do definitely do a second layer with the custom levelquik, but you'll need to do the primer on the first layer. It's probably safe to assume the rapid set brand at depot works the same, but their site wasn't loading the tech sheet.
http://www.custombuildingproducts.com/TDS/TDS-108.pdf

If you don't have a rake handy, a flat or notched trowel helps to spread it across the area as well.


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## nickko (Nov 11, 2012)

does it need to be level? I've tiled many floors that are not level but flat is what your looking for.

nicko


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## tjbnwi (Feb 24, 2009)

nickko said:


> does it need to be level? I've tiled many floors that are not level but flat is what your looking for.
> 
> nicko


Agreed, on plane and flat is what's needed.

Tom


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## builditguy (Nov 10, 2013)

I've done some SLC. I would agree that it needs a little help. At least in my experience. Not a big deal.


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## Inner10 (Mar 12, 2009)

My first experience with it was not a good one. The bag may say "self leveling" but it's really only self leveling with some babying.

First off it was a little warm when I did it, which I'm sure didn't help the working time. Secondly I was pouring over heating cables and wire mesh re-enforcement, and I had JUST enough to cover the stuff. When I poured the heating cables and mesh acted as a damn and caused high spots, the stuff sure doesn't flow like water.

Long story short is I primed and poured another layer ontop...and it was better...but not exactly a billiard table.


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## superseal (Feb 4, 2009)

There are stippled rollers you can use to help it flow and level better.

I've learned the hard way you always prime when using SLC


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## DGEC (Sep 24, 2017)

nickko & tjbnwi: Thanks for your reply. Glad to know the surface doesn't have to be perfectly level. The plane is definitely flat after the SLC. I am placing the tiles and they seem to be laying fine. :thumbsup: 

Thanks to those that reminded me about the primer. :thumbup:


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## DGEC (Sep 24, 2017)

*Prep with moisture on SLC?*

For my sub-floor I understand the tile can lay directly on the SLC without a backer board (HardiBack) as log as I have 1 1/4" plywood underneath. Normally when I use backer board I spray it down with a water bottle mister before laying the tile to prevent the backer from absorbing the moisture from the mortar. 

This is the first time I have laid tile directly over the SLC. Should I moisten it before I lay the tile? ... like I would with the backer board?

Thanks!


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## Inner10 (Mar 12, 2009)

DGEC said:


> For my sub-floor I understand the tile can lay directly on the SLC without a backer board (HardiBack) as log as I have 1 1/4" plywood underneath. Normally when I use backer board I spray it down with a water bottle mister before laying the tile to prevent the backer from absorbing the moisture from the mortar.
> 
> This is the first time I have laid tile directly over the SLC. Should I moisten it before I lay the tile? ... like I would with the backer board?
> 
> Thanks!


I did, quick wipe with a damp sponge.

Sent from my Nexus 6P using Tapatalk


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