Flooring Tile - Marbling. Underlayment for cement floor necessary?

I just removed the laminate flooring in my kitchen and noticed mold growing underneath so I'm assuming moisture is seeping through the cement foundation. I know that marble is used in showers where moisture is abundant, so would it be okay to put directly on the cement floor in my kitchen? I'm afraid that mold spots will appear through the marble flooring if I put it directly on the cement floor. Should I put a moisture barrier first?

A membrane of some sort is needed.

There are thin sheet-applied membranes, such as the ones from Noble, Schluter, etc. that will encapsulate the moisture underneath.

The other method is to use a membrane which will let the moisture in the slab be released. Schluter's DITRA membrane is applied with thinset over the slab, but its design allows moisture to be released over time. It also uncouples the slab and tile layer, which would reduce cracking translating through from the slab.

The moisture may be coming from water going through the laminate floor when you spill something on it, too. Wood sitting in water is the likely cause of the mold you're seeing.

David

stick to the question

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Let me rephrase my question: Is it bad to lay marble on top of concrete that gets moist? What would happen if I did?

Gtibri: To answer your question, if you put the marble directly on the concrete slab, you would have to deal with the movement between the two, in addition to the moisture problem.

Marble dislikes moisture as much as it does movement. Put DITRA down between them and you'll be fine.

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gtibri:you first must get a cacium/chloride test to see just how much moisture is in the slab and determine just what is causing the moisture problem wether it hydrostatic pressure or something from the top.Is this slab new?How old is it?You can set tile or marble directly on a slab as long as it is stable,something with mold growing on it is not suitable for tile or anything else for that matter,also, if there is this much moisture in this area either from above or below i dont think marble would be a very practical thing to put in this area,maybe ceramic or pocelain would be better suited for this.If there are no cracks in the slab then go directly over the concrete,if there are cracks isolate them with a crack isolation membrane and go on but first find out where and how this moisture is getting in:cool:

the MIA states--to always use a moisture barrier on grade.Not doing so is the #1 reason for failure on grade.Nobleseal is warrented for this application.