Underlayment and moisture factor

[Asriel]

Hi all.

I'm a total noob who's going to use laminate to cover my apartment's floor. I leave on the 2nd floor of an old apartment building and because the floor wasn't properly levelled beforehand the tiles were removed and it was levelled with a layer of concrete.

So my question is regarding underlayment. I hadn't done my homework when I got the underlayment went with what was advised in the shop, I think mine is simple foam. They had only two kinds, the other option being with moisture protection but the seller said I shouldn't need it in my case (I don't trust shop employees where I live much though).

From what I'm reading about underlayment if the subfloor is concrete then moisture is a factor and I picked the wrong one, but I wonder whether that applies only to ground floor subfloor or as in my case also upper floors. Pardon my ignorance but I don't see why should there be much moisture in the upper floor.

Hopefully your answers can clarify that.

P.S. I don't live in an english speaking country, english is not my native language, so forgive me if I'm not using the correct terms. Not sure whether when I say layer of concrete it's the correct term, or is it cement or mortar?

 

[Ernesto]

Asriel, you need not be too concerened unless the new layer of concrete had not dried out suffiiciently. Or there is some moisture issue from below like condensation or like a basement or water source.

In any case you will find out soon enough.There are some moisture meters out there that can give you an idea of the moisture in the concrete. Kind of pricey for just one job, or are you a professional installer?

I use a Tramex CME like the one linked below for surveying concrete for wet spots, we call them hot spots actually. If I find anything out of the ordinary then I'll perform another moisture test like a relative humidity test.

Your english is very good.

http://www.amazon.com/dp/B0083CK9N0/?tag=skimlinks_replacement-20

 

[Asriel]

Thank you for your reply, I feel much more serene now. There are no condensation humidity sources but because in what I read around it said simply that concrete needed moisture protection without elaborating I thought there was something in its inherent qualities of which I wasn't aware of, as I said I'm a newbie. It has had over a week to dry now so I guess that isn't an issue either.
Thanks again