Flooring Tile - underlayment for tiles on bathroom concrete slab?

I am going to put ceramic tiles in my bathroom with a sound and level concrete slab. My friend told that the moisture inside the bathroom can damage the tiles eventually and he recommended me to have a Cement Fiber Panels (hardie backerboard) as an underlayment for the tiles to block the moisture going underneath the tiles. So my questions are:

1.) Can I install tiles directly on the concrete slab? Will the moisture be a concern using this method?

2.) If hardie backerboard is required, how can I secure the board on the concrete slab? Drill the concrete slab with a hammer drill and put anchor screws? Is there any alternative underlayment which can be easilier to install on a concrete slab?

Thanks.

Does the floor sweat, if not you should go straight to the slab. After installing the tiles seal the grout with a sealer.

I am going to put ceramic tiles in my bathroom with a sound and level concrete slab. My friend told that the moisture inside the bathroom can damage the tiles eventually and he recommended me to have a Cement Fiber Panels (hardie backerboard) as an underlayment for the tiles to block the moisture going underneath the tiles.


THAT is so much NONSENSE you wouldn't believe. Since when does moisture have an effect on fired clay? Sense never that's when.

And you CAN NOT effectively install any backerboard over concrete, that's even farther out there in left field than the first statement.:wall:

If the floor sweats so what! Natural evaporation will remedy that problem.

If there are cracks in the concrete you may want to consider a crack isolation membrane.

THAT is so much NONSENSE you wouldn't believe. Since when does moisture have an effect on fired clay? Sense never that's when.

And you CAN NOT effectively install any backerboard over concrete, that's even farther out there in left field than the first statement.:wall:

If the floor sweats so what! Natural evaporation will remedy that problem.

If there are cracks in the concrete you may want to consider a crack isolation membrane.

To be precise, I was told that high humidity in the bathroom can create expansion problem in the mortar under the tiles and the tiles will crack. But it seems it is wrong.

I really thank for all of your replies. Now I feel more confident to install the tiles directly on the concrete slab. I thought I should use mortar set to secure the backerboard to the slab before....

Thanks.

No backerboard on concrete.

An isolation membrane maybe, but no backerboard.:)

High humidity won't hurt anything in your particular project.:)