engineered hardwood over concrete - problem

[michele525]

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Here's the story. We're trying to install engineered flooring over a concrete slab floor in our home just north of Tampa, Fl. There was a crack that went the width of the slab and the slab was uneven so the installers chipped out and patched the floor and the crack. They layed down a glue down engineered floor the next day. There was some hollowness to the floor so we insisted that be fixed. Upon pulling up the section that was hollow the installers discovered the floor was now wet underneath. (Note: They said they used a moisture reader before laying the floor and it was fine)They pulled up the entire floor (and subsequently chipped some of the slab and made a mess of my house.) The moisture reader measured high - above 9)where they had patched while we were there to witness it but they said it measure high the day before (while we were not home) in areas far from the crack and where they patched. Last week the moisture reader is measuring off the charts only along where the crack was, but a 2 to 3 elsewhere. We can find no water pipe leaks and our water bill has remained steady so we have no idea where the moisture is coming from. We've taped down plastic over the slab but there was no water after 48 hours. The home was built in the late 70's. My question - is there any kind of engineered wood floor we can put down with a measurement this high? We've looked into floating floors and have a pergo in my daughter's bedroom that is fine but hubby hates the hollow sound. I'm also concerned that putting a moisture barrier down will entrap the moisture between the slab and plastic and we will get a mold problem Also, can there be a problem with the patching material the installers used? They said it is supposed to dry in 3 hours but I'm wondering, if the crack went all the way down the slab (4") could it take this long to dry?

[Floorguy]

Thats crazy.

Had a slab here, where there was a natural spring bubbling out of.

[stullis]

Sounds like you have some real winners for installers.

Yes, the patching material, if mixed properly, could "dry" in 3 hours but probably not to the point that wood flooring could be glued over it.

As far as mold, do you have a mold problem underneath the Pergo?

wood could probably be done but you would need more extensive testing as well as a moisture barrier installed.
Cheap alternative would be to look at Konecto.

[jasonfromlaguna]

You always put a moisture barrier down on conrecte when installing eng. wood. No matter what the moisture test reads. i will not install eng. wood over concrete without a moisture barrier. I use Bostik's MVP. After that has dried for 24 hrs, you can then glue down the material.

[Barry Carlton]

you said 'moisture reader' . these are seldom accurate enough for any properly warranted floor covering (wood or not).
a more accurate moisture test (calcium chloride, rapid Rh) will give you a more reliable idea of the moisture in your substrate.
moisture barriers are absulutely necessary when needed (i know that is redundant)
but engineered floors are designed to deal with more moisture than their solid/natural conterparts.
if your have excessive moisture coming from the crack there are methods to minimize (not stop) the problem.
i strongly concur that it sounds like an installer oversight.

barry