Wet slab

[willie83]

Hi All,

I wasn't sure where this post belongs, but it has to do with water being where it should not be, so I chose waterproofing.

I moved into a newly constructed home a couple of years ago. We had laminate flooring installed and noticed, quite quickly, that the joints began to peak. Long story short, the flooring sub cut a hole in the center of our floor and found it very moist underneath. The concrete cured over an entire hot, dry summer in Southern California. All the high pressure water pipes run through the attic and we had the drain lines checked for leaks as well as the high pressure lines, so we are down to the slab itself.

Is it code to have a vapor barrier under the slab, or is it used at the discretion of the contractor?

We also learned the person who poured our slab has a habit of pouring a VERY wet slab, a high water to mix ratio. Does this cause the concrete to "wick" water to the surface?

Any thought on this would be greatly appreciated.

[Rich]

Concrete will "off-gas" vapor for a considerable amount of time. There should have been a calcium choloride test done on it to see how much water vapor was being released before laying the floor. It isn't necessarily the concrete contractors fault - the flooring installer should have checked before laying the floor.
There are several ways to mitigate migration of water from under the slab and the easiest way is to apply a barrier under the slab as well as gravel to break capillary action.