# Tilebacker w/o mortar underneath



## cleveman (Dec 28, 2007)

A neighbor called me today and said that he was just about done nailing down about 300 square feet of denshield and did he need any mortar underneath?

Is there any hope for him at this point? Will the more expensive, more flexible mortar help him? I suppose a grout like the urethane with some flex would be a good idea as well.


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## Tech Dawg (Dec 13, 2010)

Based on floors that I've torn out like that, I'll say no


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## ohiohomedoctor (Dec 26, 2010)

Should be an easy tear out for the next installer.


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## The Coastal Craftsman (Jun 29, 2009)

I have seen a few jobs done without thinset under it and they have been fine but I wouldn't attempt it.


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## ohiohomedoctor (Dec 26, 2010)

My first paid tile was 3/4 cdx, 1/2 cbu no thinset underneath, and unmodified thinset with tec grout. I saw it a few months ago and it still looks fantastic.


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## CO762 (Feb 22, 2010)

cleveman said:


> A neighbor called me today and said that he was just about done nailing down about 300 square feet of denshield and did he need any mortar underneath?
> 
> Is there any hope for him at this point?


Yeah, tell him to hire a tile professional.


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## cleveman (Dec 28, 2007)

He did mention killing himself, but I saw him this evening. He must have talked himself out of it.


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## thom (Nov 3, 2006)

The thinset bonding the two surfaces makes the floor more rigid that it would be without the thinset. In many applications that really isn't an issue. The size of the floor and the stiffness of the floor make a difference. Small bathrooms near/adjacent to a bearing wall may be fine.


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## world llc (Dec 9, 2008)

so he's worried about his install lasting... but he's using sheetrock under it?


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## world llc (Dec 9, 2008)

that stuff scares me, who knows maybe it will prove to be a good subfloor backer, it does have a robertson test result of light commercial......but it's still gyp between the glass


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## Tech Dawg (Dec 13, 2010)

world llc said:


> so he's worried about his install lasting... but he's using sheetrock under it?


That's funny :laughing: I read right through that part... :wallbash:


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## rusty baker (Jun 14, 2008)

thom said:


> The thinset bonding the two surfaces makes the floor more rigid that it would be without the thinset. In many applications that really isn't an issue. The size of the floor and the stiffness of the floor make a difference. Small bathrooms near/adjacent to a bearing wall may be fine.


The thinset isn't for bonding as much as it is to prevent voids that will cause cracking.


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## CO762 (Feb 22, 2010)

cleveman said:


> He did mention killing himself, but I saw him this evening. He must have talked himself out of it.


Prolly too cheap to spend money on a bullet. Or too lazy.
Sort of like where he wound up on his current job, too cheap to hire a professional to do it and too lazy to actually read directions. :thumbup:

Tell him to roll out ditra on top of that. I've heard that works for everything, just be sure to kerdi the seams. And use ditraset and spectralock grout.

There, that should do it, unless I missed something more expensive.


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## angus242 (Oct 20, 2007)

I recently pulled a floor that was installed with thinset under DensShield. The grout still cracked.


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## CO762 (Feb 22, 2010)

I'd not use it on floors, but I guess it works, just not my thing.

so is it stapled down or what?


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## cleveman (Dec 28, 2007)

He nailed it down with roofing nails.

I don't have anything but positive comments about denshield. I've put about 6000 square feet of it on floors. I guess my only negative is that it is not as widely available in 4x8 sheets as I would like it to be.


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## CO762 (Feb 22, 2010)

cleveman said:


> He nailed it down with roofing nails.


Gun or by hammer?



> I don't have anything but positive comments about denshield. I've put about 6000 square feet of it on floors.


I like a lot of GP products and they are a solid enough company that they'd not put out any obama products, destined to fail or a sham.


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## Big Shoe (Jun 16, 2008)

Is that stuff spec'd for floors ? Not my trade but sounds nuts to me.


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## Inner10 (Mar 12, 2009)

Big Shoe said:


> Is that stuff spec'd for floors ? Not my trade but sounds nuts to me.


Yep.


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## JHC (Jun 4, 2010)

I didn't realize it was a proper floor underlayment as well. Are the joints to be taped and skimmed as well?


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