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-   -   What size trowel for 20" tiles? (http://www.diychatroom.com/f5/what-size-trowel-20-tiles-12127/)

kemerick 10-05-2007 06:09 PM

What size trowel for 20" tiles?
 
I am laying 20" porcelain tiles on top of Hardibacker and I am wondering what size trowel I should use? 1/2"? 3/8"? 1/4"?

Or does it really matter? From what I have read, it all comes down to what provides the best coverage.

The floor is fairly level and I floated some of the Hardibacker boards to make up for the minor low spots. The floor in question is my kitchen:

http://www.emerickdesigns.com/media/.../target43.html

jproffer 10-05-2007 11:21 PM

I would think 1/4" x 1/4" would be fine. How thick are the tiles?

kemerick 10-06-2007 11:22 AM

1/4" thick

jproffer 10-06-2007 07:19 PM

1/4" x 1/4" is fine. Make sure you get 100% coverage on the tiles. Really that applies to any tile, but especially 20 inchers.

RemodelMan 10-06-2007 08:32 PM

If the tiles are ceramic 1/4" notched is cool. Otherwise, you may need a 3/8" if the tiles are rough like a slate. The trick here is to "butter" the back of the tile just before you set this into the thinset or mortar. This will greatly improve and help insure the bond without any voids. You can also maniplate the height of the trowel by adjusting the angle of contact. This will allow you to aquire a uniform "setting" so that you won't have to clean out nearly so much thinset between the joints.....

JazMan 10-07-2007 01:34 AM

I can't imagine a 20x20 tile being only 1/4" thick. I bet it's closer to 3/8" or thicker. Even most standard 12" are 5/16". Regardless of that, the texture of the backs is more important when choosing a trowel, that and the flatness of the floor. I would never use such a small notch. My standard trowel for anything around 12-13" is 1/4x3/8x1/4. On 20" I would probably choose 1/4x1/2 or 1/2x1/2. You want at least 85% coverage.

What kind/type of thinset are you going to use? It should be a medium bed mortar. Tell us what you've chosen. I hope your floor is almost as flat as your kitchen table with tiles that size. Did you double check the subfloor structure and consult a span chart to see that it'll be stiff enough for tile?

Jaz

RemodelMan 10-07-2007 07:13 AM

JazMan, makes a very important point. Your subfloor needs to be well supported without any detectable flexibilty. Otherwise, you risk poping or at least cracking grout joints and eventually loose tiles. 1" solid substrate is the industry minimum, Note: minimum. Also be sure to fill all substrate/subfloor joints. BTW these joints don't have to be sanded.

flooring dude 10-09-2007 07:42 PM

Quote:

Originally Posted by JazMan (Post 66698)
I can't imagine a 20x20 tile being only 1/4" thick. I bet it's closer to 3/8" or thicker. Even most standard 12" are 5/16". Regardless of that, the texture of the backs is more important when choosing a trowel, that and the flatness of the floor. I would never use such a small notch. My standard trowel for anything around 12-13" is 1/4x3/8x1/4. On 20" I would probably choose 1/4x1/2 or 1/2x1/2. You want at least 85% coverage.

What kind/type of thinset are you going to use? It should be a medium bed mortar. Tell us what you've chosen. I hope your floor is almost as flat as your kitchen table with tiles that size. Did you double check the subfloor structure and consult a span chart to see that it'll be stiff enough for tile?

Jaz


I agree. The key if 100% transer from floor to tile.

kemerick 10-09-2007 09:29 PM

The subfloor is good. I pulled all the 1" x 6" planks, added supports in areas where needed and put down 3/4 tounge and groove plywood wthe 3" screws and I also used 3 1/2 boxes of Liquid Nails subfloor glue. The I used a 1/4" trowel to set the 1/4" Hardibacker board.

I ended up using a 1/2" x 1/2" trowel and after pulling up a couple I was getting about 90% coverage since you guys made me all paranoid :-)

The tiles are all very close to .280". I went back and measured them with my micrometer :thumbsup:

Here is the latest gallery from working on the house this past weekend. The first couple are from a 1.3 MP camera phone so the quality is not great, but the rest show the floor tiles going in.

http://www.emerickdesigns.com/media/..._05/index.html

Thanks again for all the advice...

JazMan 10-09-2007 09:31 PM

Thanks. While 100% would be nice, it's not necessary for interior tile work. I think the standard is about 85% for floors. Outdoor work requires 100% to avoid place for water to collect, freeze, then cause trouble.

While I was typing, you were posting....Great, the new info sounds good to me.

Jaz


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