# 20x20 tile



## Norrrrrrrrrrrrm (Jan 20, 2007)

Hey guys/gals,
I am about to put 20x20 ceramic down and I wanted to make sure I am right or wrong on my trowel notch. I pretty sure I need to use a 5/16 deep trowel, am I right? Thanks.


----------



## hatchet (Oct 27, 2003)

The bigger the tile the bigger the notch is what I've always done. I wouldn't do less than 3/8" deep with 1/4" spacing.


----------



## cleveman (Dec 28, 2007)

Read your sack of mortar. I think they'll recommend a 3/8 x 1/4 on even 12x12 and up, maybe a 1/2 x 1/2 on 20x20's.

The tile guys must be off tonight. I'm surprised this hasn't started WWIII.

Post a thread on how to do a balcony or something and we'll see the fur fly.


----------



## Norrrrrrrrrrrrm (Jan 20, 2007)

Yeah I have do have a 3/8 x 1/4. I thought it was a 5/16., I was wrong...boo hoo.


----------



## JazMan (Feb 16, 2007)

Hi Norm and Rich,

There is no single correct answer to this. Lots of wrong ones though. With 20" tiles with a standard textured back I would recommend either a 1/4x1/2x1/4, or I might lean towards a 1/2x1/2 trowel, even larger might be needed?

Before you start the installation, can you tell me what the substrate is? If it's a wooden subfloor, have you consulted the framing and subfloor sheet requirements for tile? If it's a slab, are there any cracks or control joints or cuts? In either case that floor had better as flat as your kitchen table.

Specifically what thinset are you planning to use? Get back with answers to my questions above before you do anything.:thumbsup:

Jaz


----------



## angus242 (Oct 20, 2007)

I have been taught it's more of the back of the tile that determines notch size. Besides, the bigger the notch size, the more mortar your putting down and there's a real good chance you're gonna have lots of mortar oozing from between the tiles. On ceramic that size, you'll probably need to experiment with back buttering too. I guess it really depends on how level the floor is. But remember the purpose of the mortar is to adhere the ceramic to what's under it, not to act as a floor leveling compound. You can make up some of the leveling with mortar but you shouldn't rely on it.
Start with your 3/8 x 1/4, mix a small batch and test a few pieces. Better to find out then that your trowel is the wrong size than to have a full bucket of mortar and realize it then!


----------



## Norrrrrrrrrrrrm (Jan 20, 2007)

JazMan said:


> Hi Norm and Rich,
> 
> There is no single correct answer to this. Lots of wrong ones though. With 20" tiles with a standard textured back I would recommend either a 1/4x1/2x1/4, or I might lean towards a 1/2x1/2 trowel, even larger might be needed?
> 
> ...


Thanks for the concern, my mother doesn't even care this much! It will be on a wood floor and I am using hardi backer as the cbu. It has 2x10 underneath at 16 o.c. I already went around and screwed the plywood(nalied previously) down for addition hold. The floor is quite flat and is only about 10 years old. I was going to use a modified thin set by laticrete. It is supposed to be for large format tiles.
where can I get the frmaing and subfloor sheets?


----------



## angus242 (Oct 20, 2007)

You can check with the John Bridge Deflectolator to make sure you're good to go.

http://www.johnbridge.com/vbulletin/deflecto.pl


----------



## Bud Cline (Feb 12, 2006)

:thumbsup:


----------



## Tom R (Jun 1, 2004)

I've always used a trowel with a tooth-depth that's equal to the thickness of my tile.


----------



## Norrrrrrrrrrrrm (Jan 20, 2007)

Bud Cline said:


> :thumbsup:


Does this mean I'm good to go or are you just happy to see this thread?


----------



## Norrrrrrrrrrrrm (Jan 20, 2007)

Tom R said:


> I've always used a trowel with a tooth-depth that's equal to the thickness of my tile.


That was sort of my thought too. I used a 3/8 deep on some saltillo with a dollop a while back and 1/2 seems to thick for ozzing purposes as angus was saying.


----------



## Bud Cline (Feb 12, 2006)

I hate like hell to say anything around here anymore.:sad:

The :thumbsup: was two-fold because the information given was in my opinion good information and everyone seems to be under control......so......:thumbsup: (Not that my opinion matters.)

Nothing to add.:whistling

Well OK OK OK.

Keep a bucket of water and a sponge at your side at all times and if the thinset purges you can clean it up immediately.

Twenty inch tile can be a bummer if the subfloor isn't perfectly plane and they usually aren't. Spread the thinset and use the flat side of the trowel to "key" the thinset into the substrate and THEN comb the thinset in straight lines. THEN if needed you can skim some thinset onto the back of the tile using the flat side again. I have found "back-buttering" is usually required with tile that big.


----------



## JazMan (Feb 16, 2007)

As I said there are many variables. You will probably have to try several trowels? Start with whatever you think and set about 2 tiles. Lift then right away to check for thinset transfer, you want at least 85% coverage. If you don't have it, go to the next one. Make sure the thinset is mixed fairly stiff, but workable. 

If it was me and I was using a medium-bed mortar, (which one?) as it appears you are, I would not even consider the 1/4x3/8x1/4, that's my standard trowel for 12-13" tiles. I would start with the 1/4x1/2x1/4 but have a 1/2x1/2 standing by. They even make a 3/4" for certain situations. Remember when the tiles are beat-in, you should have a thinset thickness of a minimum 3/32-1/8", even a little thicker would be good with those huge things. Also remember, a trowel with 1/2" deep notches does NOT leave 1/2" tall ridges of thinset.

As for the subfloor system, we also need the unsupported span of the joists, species and grade if you can read that info off the joists and type of subfloor, thickness and number of sheets.

Jaz


----------



## Floordude (Aug 30, 2007)

20x20.... ½x½x½

13x13 is my limit for 3/8 notches.


----------



## orson (Nov 23, 2007)

According to Taunton Press "Tiling Complete" 18 inch square and larger porcelain and stone tiles, Average 30 SF to 40 SF coverage per 50lb bag thinset,

trowel size: Square Notch: 3/4inch by 9/16 inch

www.rubycon.us
Ruby Construction LLC 
Lancaster Kitchen Remodeling
Lancaster Bathroom Remodeling


----------



## Bud Cline (Feb 12, 2006)

Like they would know!

The size of the tile IS NOT the only consideration.


----------



## orson (Nov 23, 2007)

I figured I'd copy it straight out of their book and see what kind of flack I got since you guys are all quoting lower notch sizes. I usually find Taunton books to be pretty good, oh well.

www.rubycon.us
Ruby Construction LLC 
Lancaster Kitchen Remodeling
Lancaster Bathroom Remodeling


----------



## Bud Cline (Feb 12, 2006)

"Taunting Books"?
"Pretty Good"?

Is that like "military intelligence"?

So where is it?


----------



## orson (Nov 23, 2007)

I must be even denser than usual, I'm not catching your drift....I take it you don't like Tauton Press books?

www.rubycon.us
Ruby Construction LLC 
Lancaster Kitchen Remodeling
Lancaster Bathroom Remodeling


----------



## Tom R (Jun 1, 2004)

orson said:


> I must be even denser than usual, I'm not catching your drift....I take it you don't like Tauton Press books?



Taunton Press books are definitely the most informative available, IMO.

And I have 'scores' of books . . .


----------



## Bud Cline (Feb 12, 2006)

All of those books have something to offer. None of those books seem to follow an "industry line" too closely when it comes to approved methods. Haven't seen any of the recent Taunting publications, maybe they have improved although I doubt it. Some of the authors are quite informed and been around a long time but some of the information is shoot-from-the-hip at best in my recall.:whistling


----------



## Tom R (Jun 1, 2004)

Bud Cline said:


> All of those books have something to offer. None of those books seem to follow an "industry line" too closely when it comes to approved methods. Haven't seen any of the recent Taunting publications, maybe they have improved although I doubt it. Some of the authors are quite informed and been around a long time but some of the information is shoot-from-the-hip at best in my recall.:whistling



If you feel you know more, - - I'm sure there are publishers waiting . . . :shifty:


----------



## Bud Cline (Feb 12, 2006)

Yow I know I know, you and Coops must have the same manager. I'm done with this thread.


----------



## Tom R (Jun 1, 2004)

Bud Cline said:


> Yow I know I know, you and Coops must have the same manager. I'm done with this thread.



I have no idea what you're referring to, - - but I'm sure it's quite irrelevant in the grand scheme of things . . .


----------



## HS345 (Jan 20, 2008)

With 20x20 tile I wouldn't even consider anything smaller than a 1/2x1/2 square notch, and even with that I'd back butter.

Personally, I would use a 3/4" u-notch and skip the back buttering. But that's just me.

As for the oozing problem, I would rather contend with a little oozeage cleaning than have poor coverage under the tile.


----------



## Floordude (Aug 30, 2007)

Guys besides a tool to get the mortar on the substrate. A trowel is a measuring tool. The notches measure out the amount of mortar that gets on the substrate. 

OK, if a 3/8 trowel gets coverage on a smaller tile. It is in theory, going to get the same coverage on a bigger tile. Why would it not, if the substrate was as flat as a pane of glass? How thick is the mortar bed under the tile. It is going to be the same, for all sizes of tile. This is just common sense. Now, go to a bigger notching. Are you going to get a better bond, if the smaller notch provided, equal and plenty of coverage before. 

The kicker is, the flatness of the substrate and the profile of the back of the tiles. The bigger format of tiles makes the ability to level the tiles harder with less mortar, and you will not get near the coverage because of it.


----------



## Bill_Vincent (Apr 6, 2005)

Tom, What Bud's referring to is that fact that most books on tile setting aren't worth the ink used to print them. Unless they're written by someone Like Mike Byrne, or Tom Meehan, I wouldn't trust them.

As for the whole trowel size thing, with a tile that size or larger, the SMALLEST trowel I'd consider using is 1/2x1/2, and that's only with flat troweling the back of the tile, and ONLY if the subfloor is just about perfectly flat. Otherwise, it's 1/2x3/4, and it's medium bed mortar instead of thinset, and preferrably, they'd be mudset, instead. For large format, I'll choose mudset any day of the week, if I've got anything to say about it (I know-- that isn't very often). Otherwise you're pulling your hair out to get a perfectly flat floor.


----------



## HS345 (Jan 20, 2008)

Floordude said:


> OK, if a 3/8 trowel gets coverage on a smaller tile. It is in theory, going to get the same coverage on a bigger tile. Why would it not, if the substrate was as flat as a pane of glass? How thick is the mortar bed under the tile. It is going to be the same, for all sizes of tile. This is just common sense. Now, go to a bigger notching. Are you going to get a better bond, if the smaller notch provided, equal and plenty of coverage before.


While this would seem to make logical sense, in the real world, it does not.

Large format ceramic tile tend to be "domed" a little bit, even though they may not appear so to the naked eye. This makes it impossible to get good coverage in the center of the tile with a smaller notch, without adding extra mortar to the center of each tile. This will only slow you down.

You do make a good point about the extra mortar being needed to keep larger tile on plane, one that I failed to mention in my last post. 

Hey there Bill, you look very familiar to me, hmmmmm, I just can't place where I've seen you before.:cheesygri


----------



## Bill_Vincent (Apr 6, 2005)

Yeah, I'm a tile slut. I get round.   

I may be easy, but I ain't CHEAP!!


----------



## Twust1285 (May 7, 2008)

1/2x1/2in is the standard. Unless there are other things that need to be considered, like the floor being really bad, but the point is on a 20x20 I would never go below a 1/2x1/2 trowel, the tiles are just too big, and no floor is perfect. Most of the builders I sub for don't mind (so much) time or money, so for me I usually will just mudset tiles of that size and up. Also anything over a 16x16 is a new price range, it just takes ALOT more time to set them right, level and with no lippage.

P.S. I just read Bill's post after I posted, did not mean to repeat, I read the post and replied, and this is why I like reading Bill's posts our work seem to be similar, and not to mention most of the other guys on here try to say that the way I do things (mudset) is a dead art, takes too long BLAH, BLAH, BLAH. If you do not have enough time, and you really should mudset then you should fight for time, and money. It's worth it for me, less headaches honestly, and getting paid in the high $20/sqft always works for me also.


----------



## jarvis design (May 6, 2008)

I have found that the flatness of the floor is so important with larger tiles. 

A 1/2 x 1/2 trowel, once applied and the tile set will yield about an 1/8" of mortor - of course depending on the texture of the tile, etc.

Whatever trowel you are using, always lift a tile to check for coverage.

I believe that 90% transfer is what you are going for (minimum), unless doing exterior where you need 100%.

www.jarvisdesignbuild.ca


----------



## nwtile guy (Feb 13, 2008)

I did a floor a couple weeks ago with 20 by 20's and used a 3/8 by3/8 notched trowel and it worked great. The floor was nice and flat though! I agree with most of the guys here and have that 1/2 incher ready to go.


----------



## Twust1285 (May 7, 2008)

I personally would never go less than a 1/2x1/2 on a slab there is just no way the floor is going to be level or flat enough. The way these guys poor slabs there are rolls and valleys and pitches where there should not be. The only time I would go less is if I would to screed the entire floor of MYSELF first, which i have done before on decks and also inside of large homes when flagstone style mudset was not an option either due to price or Rinker being out of my special sand which has been alot lately.


----------



## OCRS (Apr 29, 2008)

:no:


There used to be a post right before mine. It was a spammer selling tools or something. It started with "thanks,....tools..." and then a web site. That's why I'm doing the shake the head thing.


----------



## Bud Cline (Feb 12, 2006)

Twust,

Aren't you the guy that is selling-off tools and pulling up stakes and moving 1300 miles because you have no work where you are now?:whistling


----------



## Bill_Vincent (Apr 6, 2005)

Not for nothing, but I agree with him. Anything less than a 1/2x1/2 on tile that big, and you're asking for trouble. Even with the 1/2x1/2 you're going to need to flattrowel the back of the tile. I'd be willing to BET that you won't get adequate coverage with 1/4x3/8, unless maybe you notchtrowel both the floor and the back of the tile.


----------



## MattCoops (Apr 7, 2006)

Bud Cline said:


> Yow I know I know, you and Coops must have the same manager. I'm done with this thread.


Why do you have my name on your tongue?

Not for nothing, but if you need a book, or even a "standard" to tell you what size trowel to use for a job then you should stay in the library and off the jobsite.

Mix up your thinset, slap it down and trowel it, beat in your tile. Then lift your tile up and check your coverage. 
Call me a rebel, but if you're doing residential work, even the standard doesn't even call for 100% coverage. It's not hard to achieve.


----------



## R&D Tile (Apr 5, 2005)

Good thread, carry on.:clap::w00t::whistling


----------



## ridewags (Jun 5, 2008)

1/2x1/2 is what I would be using


----------



## Twust1285 (May 7, 2008)

Matt are you trying to say you DON'T need 100% coverage???????? because that's kindof promoting hackers to come out of the dark corners, and after lots of effort by quality subs in my area to push them INTO the dark corners of the world that is counter productive. No one is going to get 100% one every single tile they EVER set, but tat is certainly what I try to achieve when i set tile. I don't like hollow spots. You need to use a 1/2 trowel AT LEAST for 20x20's, as I stated earlier I would much rather just mudset a 20x20 rather than troweling all of the thinset. No slab is straight and level enough to just run it with a 1/4in or even a 3/8" trowel. I would never go below a 1/2x1/2 in trowel.


----------



## Twust1285 (May 7, 2008)

Bud Cline I am not moving because I have no work. I am moving because I can;t stand the quality of my competition any longer, and i can no longer compete with the pricing. It really aggrivates the **** out of me so I'm going to go with my woodworking skills up north. There is no way I can install tile and keep the quality high for under $3.00/ft just no way, and I am very tired of trying. One of my last jobs was a 25,000 square foot residential home for the owner of PODS, and it was 100% mudset marble, you don't get jobs like that if you don't know what you are doing buddy, and it was kinda rude of you to try to make me look like some butch, and with your comments it makes me think you may be one of the guys I am leaving Florida because of.


----------



## Bud Cline (Feb 12, 2006)

Just wanted to see if I could get you stirred up one more time.:thumbup: I get a kick out of igniting hotheads. Sorry, just my weird sense of humor.:laughing:

The guys over at the woodworking threads will be hearing from you soon?:clap:


----------



## MattCoops (Apr 7, 2006)

Twust1285 said:


> Matt are you trying to say you DON'T need 100% coverage????????


No. That is what the TCNA says. Although they state you DO need 100% coverage in commercial applications.

It actually is 100% POSSIBLE to achieve 100% coverage. You just need to try. arty:


----------

