Concrete slab moisture and new bamboo laminate

[Miguel G]

Hi, great forum, already learning. We had some rain getting under our laminate floor in one of our rooms that I think stayed a few weeks there until we noticed the leak, fixed it and removed the laminate completely, disinfected, etc. I now have the bare concrete drying with a dehumidifier for several days now ( airtight room, closed ac running at 30% RH). I have a relative moisture meter, dielectric type, that measures a large difference between the “unnafected” areas and areas that had water ( coincidentally darker in color)...difference is as large as 60% and unchanged for days despite the dehumidifier. Meter is relative, so if I assume concrete is dry where I had no water, that reading is my reference (40% in my case)...See pics.

I already ordered a set of “CALCIUM CHLORIDE TEST” to check for absolute moisture per laminate manufacturer....

My question is:
How bad do you think the situation of the slab is?. How long do you think until I can try measure or install laminate (bambu self locking). Until all the slab is about same color/relative moisture readings?.... Area is about 140sqft.


Thanks for any advice.

 

[Jon]

Could moisture be coming up underneath the concrete slab where that crack in photo 3 is?
Maybe there is no plastic between the earth and the concrete when the concrete was poured originally?

 

[Miguel G]

As I said, water came from a roof leak. The area around the cracks is not discolored and does not measure high moisture readings

 

[Nick]

Put a fan in the room .. Get the air circulating ..

 

[Miguel G]

Done!...thanks....any idea how long will it take?...days, weeks, months. Tks

 

[Jon]

As I said, water came from a roof leak. The area around the cracks is not discolored and does not measure high moisture readings

Why I asked was that in my experience any water which has been laying on top of the concrete will dry a lot quicker once the concrete is exposed to moving air as compared to water coming up through the slab

 

[Nick]

We always put two dehumidifiers in the room, and a few fans .. Depending how wet the concrete is it can take a week or more ..

 

[Miguel G]

Thanks guys!

 

[Nick]

 

[Ernesto]

In some situations like that where there is a time deadline I will use a trowel on vapor retarder like Bostik MVP4 plus six mil plastic. What type of underlayment/vapor retarder are you using? Manufacturers name.....