We are moving into a home and the flooring needs replacing. We'd love to put down nice tile in the main living areas.

Currently there is carpet and pad over concrete slab. The floor *seems* to be true and level, but we haven't pulled the carpet yet to be sure.

My question is can I install 16in tile directly to the slab or should I install cement backerboard first?

Directly to the slab is fine. If the slab is sound and clean and free of old sealers you can't get a better base.
Be very watchful on setting the tile in a full bed of thinset. Large tiles being so wide there is a tendency for installers to not get full spread and you will get a "pocket" and a hollow sound to the tile in spots and a chance of a crack down the road. Check with the tile specks and you may need to add laticrete in the thin set for movement proposes. And you are sub grade and that can change the thinset application here. Again check a real tile store for better information and not just the box stores that just sells and really not qualified as prof installers. The thing you may want to look for is cracks in the crete floor. A control joint could be here to address movement in the floor Or if a lot of cracks in movement durarock could help minimize the chances for cracks later but it won't completely stop it.

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Steve,

You can not and have no reason to install a tile backer board on a concrete subfloor. Once you remove the carpet and inspect closely please return to this thread with details.

Generally, you will need a slab that has no sealers or curing agents. No cracks and it must be flat. Let us know.

Jaz

Just on a side note I would agree with jazman on the no reason for a backer board. But I want to pass this along. I'm a G.C. contractor for 30 plus years and I do work In Puerto Rico what I thought was so dumb and odd was the Puerto Ricans would build a whole concrete house (which 99% are built that way including the roof.) They are the tile kings usage wise. Here is what they do to set the tile. The lay a 2x4 on top of the cured new concrete floor and use that as a guide in control thickness. They set the tile right in the new wet 1 1/2 concrete floor. I thought what a waste! Then I looked at the old homes and even though the temps are the same almost of the time They RARELY get cracks in the tile. I helped build a 3 story beach front bed and breakfest there as a construction worker and asked WHY do you re pour concrete on top of good crete to set tile. The answer was they get small earthquake tremmers which the buildings concrete floors may get hairline cracks as the building adjust and cures. The 1 1/2" extra floor helps creat a barrier sub-straight to the original floor doesn't telegraph the crack to the tile and the 1 1/2" extra concrete is a buffer for that. The duroarock I mentioned would act as that sub straight "buffer" for lateral movement. Ive been tiling for 25 years and I would have never know this in the states until I saw how the islands kings in tile there whole house and porches and even driveways. So I thought I share that for reason of "backer board"
Jazman you are correct in your advice not trying to say otherwise. I was blown away when I did work In the crib and saw how the address sub floor cracking in the future

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