# Kitchen Flooring



## kneedeep (May 30, 2008)

jpollman said:


> Tile would be a good choice, but I've got to disagree with one thing you said here. I know that I'll probably get blasted for this but I would NOT use 1/4" backer board for a floor! Up until a few months ago that was always my position and I never used anything but 1/2" backer for floor tile. Back in April I had a customer that wanted tile put in her kitchen, dining room, pantry area, and laundry room. There was a height issue with the dishwasher though. If I had installed the marble that she wanted with 1/2" backer, she would not have been able to remove the dishwasher if/when it needed to be replaced. She had just had granite counter tops installed last year so that meant that the dishwasher was pretty much locked in if I used the 1/2". I tried to tell her that she'd have to select a thinner tile in order for me to do the job. I've had people tell me that you can use 1/4" for flooring with no problems. The guys at the tile place said it was no problem. I broke my own rule and listened to them. I installed the 1/4" backer in a bed of thin set and screwed it down. Then set the marble in the thin set and grouted it. The job came out beautifully. I finished the job about four months ago. Two days ago I get a call. Guess what, it's her. She's got a crack running right through the tiles in three different areas! She said it's just a hair line and not too big yet but it's there. This is in a condo that's about seven years old. I have a feeling that because of the weight of the marble the floor is settling and causing the tile to crack. Needless to say, that's the *LAST TIME* I will ever use 1/4" backer on a floor!! I should have known better.
> 
> I've been doing ceramic tile and marble for a long time and done many jobs using 1/2" backer. Not once have I ever had a job that tile cracked like that.
> 
> John


JP
I used to mud everything but now nobody wants to pay for it. I used 1/4 inch hardy in my own house with slate:yikes: because of highth and have had no problems with it at all. I used the strongest latex modified thinset I could (D-70) spread the floor, screwed it down and taped the seems and its one of the strongest floors I have ever put down. I was sceptical because like marble it is very soft but I'm a believer now. As far as Durock goes I cant stand that stuff it is a mess to work with and it is way more flexable then Hardy. With that said I wish I could go back to mudding!


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## Jaz (Oct 16, 2009)

John and all,

1/2" is for walls, floors and counters. 1/4" is for floors & counters. CBU's add NO structural strength to the floor. The purpose of cement backers is to have a tile-friendly surface to bond to. Your failure is not due to using 1/4" backer if installed correctly.

I would suspect an inadequate subfloor system instead. You may not know it (?), but natural stone tile floors require a subfloor that is much stiffer than if you were installing ceramic or porcelain tiles. Both the joists and subfloor should meet or exceed L720 deflection, while L360 is good enough for regular tiles. I'll bet you didn't sister the joists or add a second sheet of underlayment that would be required to meet L720. 

Me....I would have used Ditra once the subfloor met specs.

Jaz


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## kneedeep (May 30, 2008)

The problem with Ditra is it is to dang expensive and takes twice the amount of thinset. Yes it's faster to use but not the much.


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## WALLEYE MIKE (Jan 7, 2001)

I used 1/4" on my floor 7 years ago. No problem. Plywood subfloor. Screwed all squeaks and made sure it was solid. Thinset and screwed the backer board. Had a height issue also. No go with 1/2". Not a single crack.


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## Jaz (Oct 16, 2009)

Well of course Ditra costs more, it's better too. Ditra offers many benefits over cement backer boards. I'm more concerned about doing the job the best way, but in the end I charge the same for Ditra installed as for CBU's. Yes I know I'm screwing myself a little but that's the way it goes.

I try to get a little extra for installations over Ditra because it takes more time and uses more thin set too. But it's tough out there. I'm competing with a bunch of hacks who should be doing something else. Most are unlicensed and not sure what income they report. Glad I'm semi retired now.

Jaz


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## Greenbush future (Sep 8, 2005)

jpollman said:


> Tile would be a good choice, but I've got to disagree with one thing you said here. I know that I'll probably get blasted for this but I would NOT use 1/4" backer board for a floor! Up until a few months ago that was always my position and I never used anything but 1/2" backer for floor tile. Back in April I had a customer that wanted tile put in her kitchen, dining room, pantry area, and laundry room. There was a height issue with the dishwasher though. If I had installed the marble that she wanted with 1/2" backer, she would not have been able to remove the dishwasher if/when it needed to be replaced. She had just had granite counter tops installed last year so that meant that the dishwasher was pretty much locked in if I used the 1/2". I tried to tell her that she'd have to select a thinner tile in order for me to do the job. I've had people tell me that you can use 1/4" for flooring with no problems. The guys at the tile place said it was no problem. I broke my own rule and listened to them. I installed the 1/4" backer in a bed of thin set and screwed it down. Then set the marble in the thin set and grouted it. The job came out beautifully. I finished the job about four months ago. Two days ago I get a call. Guess what, it's her. She's got a crack running right through the tiles in three different areas! She said it's just a hair line and not too big yet but it's there. This is in a condo that's about seven years old. I have a feeling that because of the weight of the marble the floor is settling and causing the tile to crack. Needless to say, that's the *LAST TIME* I will ever use 1/4" backer on a floor!! I should have known better.
> 
> I've been doing ceramic tile and marble for a long time and done many jobs using 1/2" backer. Not once have I ever had a job that tile cracked like that.
> 
> John


 
John the job you bid at my rental was completed with 1/4 Backer and the same issue happened with the crack in the kitchen. 1/2 sure seems right IMO.


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## april_luv (Sep 9, 2010)

hi guys......

you just made my day. now i can solve my problem and able to work it properly. i will make sure that i will to it right........thanks for sharing guys...


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## jpollman (Jan 14, 2001)

Greenbush future said:


> John the job you bid at my rental was completed with 1/4 Backer and the same issue happened with the crack in the kitchen. 1/2 sure seems right IMO.


I didn't see this reply until just now. Sorry to hear that GBF, it's quite obvious to me that 1/4 is NOT suitable for floors even though I've been assured by a number of people that it is. I'll never use it again even if the customer wants to sign off on it. Down the road when it cracks and looks like crap, my name is still on the job. They probably won't mention the fact that they were warned but decided to use the wrong substrate. If I refuse to use it, the problem will be averted.  If they insist, they can find another installer.

John


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## Jaz (Oct 16, 2009)

You guys can believe what you want to, but the fact is that CBU's add NO structural strength to the floor system. Half inch is not stronger than 1/4". As a matter of fact one 1/4" backer, Hardie, scores a higher compression rating than its 1/2" brother. These things have been tested many times. 1/4" is made for floors. 

You can not concluded that while a floor job worked well using 1/2" but another failed using 1/4", that it is obviously the difference in the backers. That makes no sense. They were two separate installations under different conditions. The failure was caused by another factor.

As I said before.....I would have used Ditra....but...........

Jaz


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## jpollman (Jan 14, 2001)

Most of the tile installations I've seen have had at least a 1/2" backer used. I haven't seen a problem with tile cracking on many of those. I haven't seen too many installations using 1/4" backers. Just the one that I did, one that Walleye Mike did, and the one that GBF had someone do with 1/4". Of those three installations, two of them have cracked in a very short time. I think I can draw a pretty obvious conclusion from that fact. 

Yes they are all different installations with different circumstances, but 66% of those installations have failed. I'll take what you said in an earlier post about 1/4" backer being fine for floors if the sub-floor is specifically engineered and built to a spec to allow it. But most installations I do are in existing structures and it would be cost prohibitive to bring the sub structure up to that spec. It's much easier and less expensive to just use a 1/2" board and be done with it. We're just going to have to agree to disagree on this point I guess.

Take care.

John


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## WALLEYE MIKE (Jan 7, 2001)

jpollman said:


> Most of the tile installations I've seen have had at least a 1/2" backer used. I haven't seen a problem with tile cracking on many of those. I haven't seen too many installations using 1/4" backers. Just the one that I did, one that Walleye Mike did, and the one that GBF had someone do with 1/4". Of those three installations, two of them have cracked in a very short time. I think I can draw a pretty obvious conclusion from that fact.
> 
> Yes they are all different installations with different circumstances, but 66% of those installations have failed. I'll take what you said in an earlier post about 1/4" backer being fine for floors if the sub-floor is specifically engineered and built to a spec to allow it. But most installations I do are in existing structures and it would be cost prohibitive to bring the sub structure up to that spec. It's much easier and less expensive to just use a 1/2" board and be done with it. We're just going to have to agree to disagree on this point I guess.
> 
> ...


Possible installation and how the house was originally built.

My house is 40 years old. Any settling should be done. House was built by a carpenter from Chrysler (his own house) Most everything in the house is square and plumb as best I've seen. I believe my subfloor is (2)1/2 sheets of plywood. I also rescrewed (was previously nailed) the whole floor. It had a couple squeeks


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## jpollman (Jan 14, 2001)

That's probably why yours worked Mike. Sounds like a pretty solid and stable sub floor. If it's two half inch pieces of ply you've got a quarter inch more than most floors because they're normally 3/4". If you screwed a lot of it down before installing the backer that is why it's so stable. I can see 1/4" being fine if the sub floor is very substantial. But in most cases it's not. 

John


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## Jaz (Oct 16, 2009)

Oh boy.....

You don't have to believe anything I'm telling you, but concluding that 1/4" CBU is no good because 2 of 3 jobs you mentioned have cracks is kinda scary. That is no way to test anything. If you want to educamate your self a little, I suggest you join one of the many tile forums available on the net and confirm what I'm telling yous guys. I would not steer you wrong! 

Now, let me say that when I used CBU's for floors, most often I also used 1/2". Lots of Durock, although i think PermaBase was the best. 

FYI, the specs you don't want to build up to, are the same for all tile installations, whether you're using CBU or membrane etc. It is L360 deflection for both joists and subfloor. I'm sure you carpenter fellows understand that. It is also the minimum standard for house building, so not much to do to meet minimum specs. Of course I don't recommend building to the lowest standard, but that's it. 

BTW, it is unlikely that a floor was built with two sheets of 1/2" ply. Anything is possible however. If the house is kinda old it may be 1/2 + 5/8". That would make a pretty good floor. Two sheets of half is not considered very good for subfloor. Matter of fact, it's weaker than a single sheet of 3/4". 

Jaz


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## kneedeep (May 30, 2008)

jpollman said:


> That's probably why yours worked Mike. Sounds like a pretty solid and stable sub floor. If it's two half inch pieces of ply you've got a quarter inch more than most floors because they're normally 3/4". If you screwed a lot of it down before installing the backer that is why it's so stable. I can see 1/4" being fine if the sub floor is very substantial. But in most cases it's not.
> 
> John


John do you thinset you CBU down and screw it?


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## jpollman (Jan 14, 2001)

kneedeep said:


> John do you thinset you CBU down and screw it?


Yep.


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