First Tile Job, laying ceramic on concrete floor. How thick should the thinset be? I put down a layer about 1/4 thick but after setting tile it seems that the tile is flush to the floor.

 

It depends what size format the tile is.

1/4"x1/4"x1/4" is ok for tiles up to 8-10"

I use a 3/8"x3/8"x1/4" on bigger format up to 14x14.

Over that and it is 1/2"x1/2"x3/8"

 

What exactly do the demensions signify? If you put down 1/4 inch of thin set, how high will this raise a tile?

 

Geigerman,

Using the proper trowel doesn't raise the tile that much. It would depend on how fluid you have mixed your thinset. Your thinset should "hold the ridge" created by the trowel.

But there is more:

The physical size of the tile doesn't have as much to do with the trowel notch size as does what the back of the tile is like. Just because a tile is a certain size doesn't dictate the final size of the trowel notch to be used.

Some tiles (of all sizes) can be very flat on the back, others can have deep and deeper depressions. Some even have a perfectly flat back with nubs that stand pround of the flat surface.

Look at the back of the tile to determine what size notch is most suitable not the dimensional size of the tile.

It stands to reason the deeper the depressions in the back of a tile the more thinset (adhesive) that is required...thereby a larger notch. A flat smooth tile requires a smaller notch ("v"-notch maybe).

To answer your question...
In your example (1/4 X 1/4 X 1/4) the inch fraction represented means that the notch is 1/4" wide and 1/4" deep with a tooth also of 1/4" width.

 

Bud,

Thanks for the information, it was very helpful.
Geigerman

 

Tool out the thinset with the notched trowel. Put a single tile down. Seat it firmly. If it squirts out from under the more than a very little, too much. It will fill the grout joints. Pull the tile up. Look at the back. You should have 100% coverage with thinset. If not, to little. Use a rtowel with a larger tooth. Holding the trowel at an angle allows adjustment of the ridge height between notch sizes.
Find a copy of "Setting Ceramic Tile", Michael Byrne, Taunton Press. It will tell you everything.

 

100% coverage isn't necessary but anything less than 80% should be addressed before continuing. One little trick is to comb all the thinset in one direction so that when the tile is placed the highs collapse into the lows.

You don't want thinset purging upward between the tiles more than 1/3 of the depth of the grout joint. Keep a bucket of water and a sponge at-the-ready so that any purges can be quickly removed before they get forgotten.

 

I use more mortar under bigger formats because I can adjust for lippage better.

Popcicle sticks work good for mortar ooze at the edges.