# Backerboard not in mortar -- How bad is that?



## AtlanticWBConst. (May 12, 2006)

General practice is to use thinset. 

Maybe he used a different kind of adhesive like Liquid nail?

Whatever the case, 'Durock' installation directions say to use thinset for their flooring installation process:

it's on page 10 of 12:

http://www.cgcinc.com/pdf/howtos/EDR_6209.pdf

Here is another intersting article:

http://www.hammerzone.com/archives/letters/flooring/tile_subfloor.htm


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## House_Amuck (Mar 18, 2007)

Thanks for the links!

I really am not able to see anything that leads me to believe there is thinset beneath the boards. He did screw the backer boards into the plywood subfloor with what looks like deck screws (have square insets in heads).

What I'm wondering though is, since I've already had one head to head with this contractor about resetting the tub--what are the consequences of saying nothing and just letting this one go by? Will my tiles crack and buckle as the durock shifts over time? I rationalize to myself that the smaller tile we are putting in would weather shifts better than a larger tile would, but I'm still a bit concerned. If there are some people that do it the way he is doing it and most of the time it's fine, then I'm inclined to not raise my blood pressure again by butting heads with this contractor.


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## jproffer (Mar 12, 2005)

Liquid Nails is not for use under durock. It remains flexible (somewhat) after it is dry. There should be thinset under the durock everywhere...if there's not make him take it up and do it right...it's YOUR home he's working on...it's YOUR money that's going to be wasted if he doesn't have thinset under the backer. It will flex into any imperfections in the subfloor. The purpose of the thinset is to hold the durock UP, the screws hold it down. Non-mod thinset is what to use. It won't stick (as much) to the subfloor below and will allow the rock to expand and contract at it's own rate, which is what keeps the grout from cracking. The lack of thinset will also void ALL warranties on the entire floor. Even the lack of thinset under one sheet, or even a partial sheet will void the warranty on the entire floor. Similar to a warranty on roofing, they will look for ANY reason to not pay it...on your roof, one nail out of place...one shingle misplaced...voids the whole roof.

Make him do it right, or not at all.

EDIT: Also, since he's taking it up anyway, and it won't cause any more work...when he puts it back...he should use the screws made for Durock, not deck screws.


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## Darylh (Jan 2, 2006)

Find out exactly what product he used for the cement board, then go to the manufactures web site and down load the installation sheet and if it says to use thinest print a copy, then ask your contractor if he used thinest and if he says "no not necessary ask him why and then pull out the installation sheet and see how he reacts. One big thing to remember is a Contractor must obey the Manufactures installation directions or the Warranty will be void.


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## JJC (Nov 8, 2005)

What Darylh said. It is important to have all the "ammo" before you confront the contractor.
Jim


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## JazMan (Feb 17, 2007)

Hi J,

It's not a matter of opinion like vanilla or chocolate. All tile backerboards MUST be set into thinset mortar if you want the job to last like it's supposed to. As mentioned above its purpose is not to keep it from shifting side to side, but to support it so that it doesn't move up and down. No amount of fasteners will stop that movement if there is no thinset under to support. No backerboard has grain, non add structural strength. The board will eventually move a hair and will crumble around the fastner.

It is not likely that this will cause tiles to crack, but I guarantee some grout cracks in 2-5 years. 

Obviously the contractor does not know as much as he should if he's going to take people"s money for his labor. I wonder what else he might not be doing right? 

Jaz


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## AtlanticWBConst. (May 12, 2006)

jproffer said:


> EDIT: Also, since he's taking it up anyway, and it won't cause any more work...when he puts it back...he should use the screws made for Durock, not deck screws.


Absolutely


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## AtlanticWBConst. (May 12, 2006)

JazMan said:


> Hi J,
> Obviously the contractor does not know as much as he should if he's going to take people"s money for his labor. I wonder what else he might not be doing right?
> Jaz


That's what I was thinking in regards to the tub issue the poster mentioned too.

That's the most pathetic thing to see....an alleged 'contractor'.... that has to be told by the homeowner to fix their substandard work .... or have to be told by the homeowner how to properly install something :icon_rolleyes: 

They should get into another line of work... (Grocery stores are always looking for more baggers)


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## House_Amuck (Mar 18, 2007)

*Images of Cement Board -- Feedback?*

So many helpful comments...thanks so much!

I can't figure out what kind of cement board this is. I looked on the web and Durock says "Durock" on it and it's not Hardibacker. Those are the only brand names I know. This board is not imprinted with anything (generic cement board?) Also, could someone tell me what type screws these are? They don't look like Durock screws (but if the product isn't Durock, maybe that doesn't matter.) I did see a cement board screw that had a square indentation in the head, but some deck screws take square bits too, don't they?

Shouldn't I be able to see thinset along the edges and between the boards? All I'm seeing is bare plywood. I'm still getting an ulcer deciding whether to confront this guy or not. Some of the board extends under some installed things, like baseboards and, worse, a kneewall. Pulling it out would be a PITA and since they are already squawking about tearing out and resetting the tub, this could get ugly and I'm not sure I'm up for it. Of course I want the job done right, too. Very frustrating. And to think we interviewed 8 contractors and chose this one! (Grass is always greener...)

If you click on these it will take you to the webshots account I created for this and other pictures of the bath are also included. (Since I'm discussing the improperly set tub on another forum.)


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## jproffer (Mar 12, 2005)

WOW...so much to say, here we go:

picture 1...there should not be that big of gaps between the durock and the wall (not Durock brand, but that's what it is BTW. The fiber imbedded rock is what I call durock).

picture 2...the sheets used were broken before they were installed I would assume. They should have been saved for cuts and small pieces. Those "holes" will fill with thinset, which is perfectly fine (if they'll do it), but it's evidence of a hack job. I'd be more concerned with the "what else" factor. I don't see any thinset under what I can see. The mesh is kinda in the way, but I don't think there is. You would see it between the sheets if there's a gap. It would look kinda like a comb effect. A 1/4" of thinset, a 1/4" of nothing (or very little thinset), a 1/4" of thinset, a 1/4" of nothing..and so on.

picture 3....is pretty well ok for the 10" that I can see. Except for the screws...wrong screws. BTW, this is what you're looking for. I'm in no way promoting that retailer...it was the first one out of 16,200 on google for "durock screws".

I wouldn't get worked up over it at all. He knew (or should have) that it had to be done right...if he doesn't know what that means he shouldn't have bid the job. Don't beat around the bush....just tell it flat out.. "Take that up and do it right, I don't care what it takes...do it right, or I'll find someone else who will." 

If he agrees to that pretty easily, let him off the hook for under the knee wall. He can just cut around it. Noone will be walking under the wall anyway:jester: ...but don't let it go too easily. If he tries to play hardball, then respond in kind.

As far as the baseboard, chances are there's no screws under there anyway so it will slide out when it's unfastened.


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## beer_geek (Feb 19, 2007)

I can't really tell from the pictures because I need to see more of the sheet. Anyway, IIRC from the last tile job I did, Durock has a rough side and a smooth side. The Durock logo is on the rough side and that's the side that should be facing up. Like I said, it's tough to tell but it looks to me like that has been installed with the smooth side up. Do the sheets look to be the same texture all the way around? If the rough side is up, you can see a transition from the rounded edge for a couple of inches. It would be where you'd tape it. That's kinda smooth, then the field is rough. If if all looks the same, it could be upside down. 

Per the durock website:
Board is smooth on one side for adhesive applications, textured on the other for thin-set mortar applications. 

Is he going to use thinset?​ 
I hope I'm explaining myself properly.


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## House_Amuck (Mar 18, 2007)

*No Thinset*

Tile guy says that this contractor never uses thinset--that it's not necessary over plywood that is nailed into the floor studs--that if it were a planked subfloor that might be different. That the contractor uses adhesive. When I said this is not industry standard he just shrugged his shoulders and said "I've been tiling over it done that way for 20 years and I've never had a problem." What can you do when you are up against that, really?

I need to start a thread somewhere else about the tub they set improperly. they are pulling it out now. This is such a nightmare.

I'm hoping that the durock isn't upside down, that it just isn't durock but a generic unprinted thing. I hope so.

It's awful but you get to the point where you just want them out of your house, no matter what.


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## beer_geek (Feb 19, 2007)

If he's using adhesive, then it is right. The smooth is for adhesive, the textured is for thinset.


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## JazMan (Feb 17, 2007)

House Amuck,

I sent you a PM, call me if you want.

Jaz


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## HJ1 (Oct 31, 2006)

Go to the websites for wonderboard, durock, hardibacker and any other cbu. Download the instructions and print them out. Give them to your contractor. All of the cbu manufacturers require that the board be bedded in thinset. None say its optional or not required. If this guy doesnt do it right now, you'll be paying to do it over a few years down the road and he'll be no where to be found. He's full of crap if he's telling you he's been doing it this way for 20 years with no failures. Send him here and we'll tell him how to do it right.


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## House_Amuck (Mar 18, 2007)

*We won the battle; contractors will win the war*

I know you all are right. We won the battle of having them pull out the tub and reset it. But I admit to caving when it came to our other points, (no vapor barrier behind shower wall cbu and gluing cbu on floor to the plywood instead of using thinset.) My husband is very conflict aversive and I have a lot of fight in me, but I'm just worn out. At this point, I just want them out of my house. 

So if there are any shady contractors out there--just keep being short, beligerant and hateful. Your client will eventually give up, just to get rid of you! (Of course your return business might be a problem, so be sure to cast a wide net!)

I'm not proud of giving in; I'm just exhausted.

What I'd say to anyone out there reading this who has never hired a contractor for a bathroom renovation, but is about to: make "workmanlike" a matter of contract. Don't assume they will do according to industry standard but make it part of your contract that they will do the work in a certain way (moisture barrier behind durock; durock shimmed or furred from the wall so it doesn't go out of level at the tub flange; subfloor/thinset/durock with durock screws, etc.) When you read on these forums a lot there is a certain baseline of procedure that "everyone" seems to follow. But the truth is "out there" in the construction world there are people that are doing all kinds of s##t (pardon my french) and have been doing it this way (i.e. incorrectly and badly) for years. They've made a profession from doing shoddy work, all over the city. Shocking but true. And these guys had very good references but when at one point, when the subcontractor said to me "but most people aren't are picky as you are" (is caring about level and plumb "picky?") it dawned on me that most people just aren't paying attention and don't really know what their contractor is doing, or more importantly NOT doing. And sometimes ignorance is bliss (the job LOOKS good; wish I didn't know what is wrong underneath) but most of the time ignorance will just buy you more trouble down the road.

Sorry if I sound like I'm crying into my beer--I AM a bit! I just hope somebody at least reads this and doesn't make the same mistakes we have!!

-J.


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## KUIPORNG (Jan 11, 2006)

I think if you use ditel, you kill two birds with one stone, vapour barrier and durrock... at the same time... may be it is too late for your project... but for anyone else....


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## AtlanticWBConst. (May 12, 2006)

House_Amuck said:


> I know you all are right. We won the battle of having them pull out the tub and reset it. But I admit to caving when it came to our other points, (no vapor barrier behind shower wall cbu and gluing cbu on floor to the plywood instead of using thinset.) My husband is very conflict aversive and I have a lot of fight in me, but I'm just worn out. At this point, I just want them out of my house.
> 
> So if there are any shady contractors out there--just keep being short, beligerant and hateful. Your client will eventually give up, just to get rid of you! (Of course your return business might be a problem, so be sure to cast a wide net!)
> 
> ...


No, you are right, I can't tell you how many times I am so dissapointed when I see really poor substandard work. I really feel for the property owners. 
We are currently evaluating the repair of a kitchen addition that is heaving up. The Contractor will not return phone calls to the home owner.
We just finished up a basement remodel this week that an 'alleged contractor' messed up. I have to drive out tomorrow to evaluate repairs to a messed up bathroom remodel by the same guys....

Bottom line is that there are some people that do this job simply for the money, and then there are some that want to do the best job possible on any given project and look forward to seeing a very happy customer that has a finished .... high quality job. 
We are constantly on the look out for better materials and better methods. We want all our work to be done expertly, a notch better than the best. 
We feel our customers have put their trust in us, and they deserve the best. Our goal is to deliver it .... no matter what. 
We only hire subcontractors who have the same ethics as we do. There are many contractors out there that feel the same way. 

I am very sorry to hear about what you went thru. Just realize that there are professional General Contractors out there, and when you do find them, keep their number and share it with others....


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## Darylh (Jan 2, 2006)

*Bottom line is that there are some people that do this job simply for the money, and then there are some that want to do the best job possible on any given project and look forward to seeing a very happy customer that has a finished .... high quality job. *
_*We are constantly on the look out for better materials and better methods. We want all our work to be done expertly, a notch better than the best. *_
_*We feel our customers have put their trust in us, and they deserve the best. Our goal is to deliver it .... no matter what. *_
_*We only hire subcontractors who have the same ethics as we do. There are many contractors out there that feel the same way. *_

_*I am very sorry to hear about what you went thru. Just realize that there are professional General Contractors out there, and when you do find them, keep there number and share it with others....*_

Well this just about sums it up for me too. It's the real pits hearing about situations like the one your going through and I wish these wanta bees would just stay home.....


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## someguyone (Oct 1, 2007)

The cement board that is being used, is in fact Durock brand. It is installed upside down. Durock is a specific brand of cement board (rather than a type) and has two sides; a smooth side for mastic applications and a rough side for mortar applications. For a flooring application, the smooth side should be down and bonded with a thinset mortar. Additionally, cement board screws (those aren't cement board screws that you have in there now) should be used to fasten the boards. Also, I noticed that none of the joints are taped. This is a common thing for contractors to skimp out on due to money savings for them, but if you tile over the board as is, your warranty is void.


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## mikeb33 (Sep 27, 2010)

*Any update?*

I found this thread because I have an installer here now doing what I believe is the same thing. I saw no signs of any mortar, but I unscrewed a smaller piece of Durock and it is being held down with something like liquid nails or mastic.
I wondered how the original thread starter's floor is holding up? 
Also I was looking at Durock's website and I can't actually find anywhere that indicates it has to have thinset underneath? I know it is a good practice and understand why, but like the OP, if you are going to butt heads with the contractor, I would like something definite in writing.


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## TomServo (Sep 6, 2009)

mikeb33 said:


> I know it is a good practice and understand why, but like the OP, if you are going to butt heads with the contractor, I would like something definite in writing.


Why would you need this? You're the boss, just kindly explain to your contractor how you want it done. The materials involved are pretty trivial and the cement board may be able to be reused. The purpose here is not "holding down", but more so "holding up" and the mastic or adhesive will not perform this function.


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## mikeb33 (Sep 27, 2010)

I understand why you answered that way. 
I am at fault for not specifying how I wanted it up front. Since I didn't, I don't feel it is fair to make him redo it unless it is obviously agaisnt manufacturer's directions. I could not find on USG's website where it says you need to do it.
BTW my sub floor is 3/4" T&G plywood in good shape, no water damage or obviously hi or low spots. I am hoping the worse the floor, the more the need for mortar? I've been walking all over the durock and don't hear or feel any movement or anything.


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## TomServo (Sep 6, 2009)

Well, if you truly feel it is your fault, I would just make it clear that you'll pay for it to be changed. Surely the contractor could not object to that.

All I could find was a PDF that referred to mortar or adhesive. Can you tell whether they troweled out the adhesive?

Anyway, it seems like common sense that the less variation in the subfloor, the less need for the mortar.


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## spaceman spif (Jul 28, 2009)

Oh crap...reading this thread made me realize that I forgot to put thinset down when I put in my Hardibacker flooring! I've already laid in the tile and grout! :wallbash:

This bathroom is small - only 6' x 6'. I have two layers of subflooring screwed into the joists, and it was very solid when I walked on it. I used a lot of concrete screws to screw the Hardibacker into place and I did tape and mortar the joints.

How much trouble am I in?? Please don't tell me I need to pull up the tile and grout and flooring and redo it!!


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## mikeb33 (Sep 27, 2010)

I heard them trowling it out from the floor below. I assumed it was mortar, but after they left I saw what looked like a liquid nails type of adhesive around the seams.


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## TomServo (Sep 6, 2009)

Mike,

It sounds like USG is actually OK with the adhesive, so that wouldn't give you any ammunition. There's some discussion over here.

Personally, I would prefer the thinset, too. I think its really up to you to decide whether you want to pay your contractor to redo it. I might take a 4' level to the Durock surface and see if there are any variations (in flatness, not "levelness"). If it's flat, then you should be OK.

spaceman spif,

There's no sense in worrying about it now, is there? What's done is done. BTW, the solidness is good, but is more related to the subfloor. The backer board isn't for structure...its purpose is to provide a flat, water-resistant substrate that has some "tooth" for the top layer of thinset to bond to.


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## racebum (Mar 8, 2010)

skipping on thinset is the single most common area to cut corners in my area. TONS of guys do it. on a perfectly level and clean floor i've seen it live for many years BUT, how many floors are really that level? the thinset is a void filler and prevents popping from ever occurring. i personally have never laid a cement board floor and not used thinset under. that being said one of my bathrooms was done by the previous owner back in 2002 with white marble on wonderboard, no thinset, just screwed down. so far not a problem one. the one tid bit i will share is that i've had better luck leveling the floor on screw down by mixing the thinset on the runny side. basically where you can hold a trowel line but it falls down a bit after a minute or two.


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