Why is so much mortar needed to set a tile [Archive] - Ceramic Tile Advice Forums - John Bridge Ceramic Tile


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02-29-2008, 07:50 PM
I am aware that a 1/2" notched trowel would be recommended to lay 16 x 16 inch floor tile. What I don't understand is the rational for such a thickness. A 1/2" mortar layer would certainly help to bury a high spot, but is there something additional that it is needed for.

Assume for argument purposes that I had a pefectly flat floor. Would it not be sufficeient to use a 1/4" notched trowel and also butter the back of the tile? Would the extra 1/4" of mortar provide an additional benefit?

What is driving me to ask this question is that I would like to minimize the dimensional stackup of backerboard plus mortar plus tile.


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02-29-2008, 08:19 PM
Steve~ If you have a perfectly flat floor, a 1/4" trowel will get the job done, although I generally go to a 3/8" for that size material. The only time I've used a 1/2" trowel is for Sautillio Tile . Sure...if the floor hasen't been adjusted or leveled, you may need the larger size. For myself, I'd correct an uneven floor first.

02-29-2008, 08:19 PM
if your floor is flat you can use a smaller trowel size. but by using a little larger one you are assuring you can get the tile flatter by having more of a bed to set the tile in and adjust them.

being cheap on thinset thats $20 a bag isn't worth having a floor with dips and high tile.

02-29-2008, 08:20 PM
Laz....quick on the trigger tonight aren't you ?? lol :tongue:

02-29-2008, 08:23 PM
"My cross to bear," Brian...... :lol1:

02-29-2008, 08:28 PM
Hiya Steve, Keep in mind that a 1/2"x1/2" trowel leaves about an 1/8" mudbed after bedding the tile in.

02-29-2008, 09:53 PM
You can also save yourself a little on the thickness buildup you're worried about by using Ditra instead of a 1/4" backer board.

Not only does the floor need to be perfectly flat for a smaller notch to work, the tiles themselves need to be perfectly flat as well. The bigger notch also serves to accomodate any cupped tiles or stones.

02-29-2008, 09:59 PM
The big tiles tend to be cupped a little. A 1/4 inch may barely touch the middle of some. I usually use a 3/8 notch and also skim coat the backs. Like the others said, a 1/2 inch notch doesn't leave a 1/2 thick mudbed. :)

03-01-2008, 07:36 AM
NOW I understand. I really appreciate all of the great responses. This site is really amazing,

Rd Tile
03-01-2008, 08:11 AM
And BACKBUTTER all of them while setting with the flat side of the trowel, that's more important than what size trowel you use.:)