# Leveling with Thinset?



## albertalbert (Mar 30, 2011)

I just embedded my underfloor heating mats with a self leveling mortar in my kitchen project

The result is that the mats are embedded, but there are plenty of high/low spots due to the fact I applied the leveler in stages and could never get it perfectly flat. Probably no more than 1/4" at most. I also only applied it over the mats, so it's not where the cabs will be or even under the appliances. This means that the subfloor is about 1/4" lower than the dried leveler.

My question: When I tile over, can I just use the thinset to level everything out? Will 1/2" of thinset under a tile be a bad idea? 

Thanks,


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## Ron6519 (Mar 28, 2007)

albertalbert said:


> I just embedded my underfloor heating mats with a self leveling mortar in my kitchen project
> 
> The result is that the mats are embedded, but there are plenty of high/low spots due to the fact I applied the leveler in stages and could never get it perfectly flat. Probably no more than 1/4" at most. I also only applied it over the mats, so it's not where the cabs will be or even under the appliances. This means that the subfloor is about 1/4" lower than the dried leveler.
> 
> ...


I'd install 1/4" cement board where the cabinets are going. Install it in a bed of thinset and screw it down. Then mix up more leveling compound and fill in the low spots over the heating wires.
Ron


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## albertalbert (Mar 30, 2011)

I appreciate the reply, but can I ask Why?
If I use a 4' level while tiling, why can't I use the thinset as my leveler? I used 7 bags of leveling mortar, and at 35 bucks/bag, I'm ready to be done with that...

I will do it if that's the only way to go, but I don't see the issue with doing the final leveling during tiling...


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## Willie T (Jan 29, 2009)

Some mat manufacturers recommend a leveling compound first, before thinset. Some suggest an insulation layer between the floor and the mat. Others say to just go ahead and thinset your tile right on top of the mat.

But I have never heard of one that said to 'embed' the mat in anything as you lay it out. (Did I misunderstand what you did?) Usually the mats are either adhesive backed or are taped down securely prior to spreading the leveling compound or the thinset over the mat.

BTW, make sure your thinset says it can be used with heating mats... and apply it with a plastic trowel that it won't possibly cut the wires.

Check the mfg. literature to see if you might be restricted from using thinset directly on the mat.


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## albertalbert (Mar 30, 2011)

Yep - I went by the book. I'm using SunTouch (oddly available at both HD and Lowes), and the advice I got was that embedding the mat prevents any issues with the trowel snagging the mat or worse, knicking the element.

I laid the mats, stapled them down, then poured the leveling mortar on top. Now I am tiling over that, plus next to it which has no leveling mortar or mats. Hoping to find a tile expert out there to say "no prob" or "your tiles will crack" or something.

Thanks!


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## Ron6519 (Mar 28, 2007)

albertalbert said:


> I appreciate the reply, but can I ask Why?
> If I use a 4' level while tiling, why can't I use the thinset as my leveler? I used 7 bags of leveling mortar, and at 35 bucks/bag, I'm ready to be done with that...
> 
> I will do it if that's the only way to go, but I don't see the issue with doing the final leveling during tiling...


The 1/4" cement board is to avoid a 1/2"+ pile of thinset. Leveling the variations in the field makes it easier to tile for an inexperienced tiler.
If you think you can tile over the waves, go for it.
Ron


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## Willie T (Jan 29, 2009)

Ron6519 said:


> The 1/4" cement board is to avoid a 1/2"+ pile of thinset. Leveling the variations in the field makes it easier to tile for an inexperienced tiler.
> If you think you can tile over the waves, go for it.
> Ron


Trust what Ron is saying on this. When you watch an experienced setter throw extra thinset down in low spots, it looks easy. It ain't... and it gets harder the larger the tiles are.

Nice, level floors are the novice's friend. :yes:


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## oh'mike (Sep 18, 2009)

Lash clips and wedges might be called for ----leveling with mud is a challenge (and usually a mess)

These will help you avoid lippage.LASH System by QEP

Depot sells these---figure 80 cents a tile---clips .10-each---wedged .10 each.


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## Bud Cline (Mar 12, 2006)

Okay albertalbert here's the deal.

Thinset is not intended to be used as a giant filler or levelling compound. Thinset in abundance will shrink terribly and it will take your tile with it leaving you with lippage you won't believe.

Embedding the mats in self leveller was the correct thing to do but you should have also used it in the appliance cubby holes. If you try to jury rig this situation with backerboard now you are asking for trouble.

Go bite the bullet and buy more self levelling compound and do the entire area one more time. This time around won't take as much as you used before. The areas over the mats only need about 1/8" of cover and of course you'll have to fill the low cubby areas completely. Also this next time around will be much much easier because the mats are already covered. Block out the cabinet footprint with 1X2's.

The problem with burying the mats is the mats impede the flow of the SLC. That won't happen this time. Use more primer everywhere then go to pouring. How many square feet are we talking about including the appliance cubby's.

Do what you want to but trust me...if you do it your way you'll be throwing good money after bad and may lose the entire project and you don't want that to happen with that heat in there.

Again, tell how many square feet you are dealing with and let's see how much SLC it will take this time around.


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