Hello!
I received a call from our contractor saying they are having difficulty reducing the moisture content in our concrete slab. It is currently at 95%. They poured the slab on September 28. They used a concrete with a w/c ratio of 0.55. From what I understand, the moisture level in the concrete is high. We have heating coils, but they are not turned on; they are using heaters and dehumidifiers. I asked if the painter could start his work, but they say he also needs to paint the moldings, so he must come after the floor is laid. We have chosen a Pergo floor that requires a laying moisture content of 75%. But when I contacted customer service, they said:
“The relative humidity in new production and the desire for short production times are naturally a challenge. We see that when laying, in newly produced houses, where the humidity is up to 80-85%, there is often no problem, but we cannot deviate from the guidelines we have and that comply with industry standards. Problems often arise because one has not taken into account that a longer acclimatization time is needed for the floor at higher humidity. Higher humidity in a newly poured slab is, after all, a minor problem because you know the slab cures. High humidity in an 'old' slab is another issue."
Under the laminate, a Tarkoflex with a built-in vapor barrier will be laid.
I also spoke with a moisture expert who says you can lay laminate flooring when the slab is at 90%.
What are the risks, what might happen? What guarantees can we claim? How low does the slab need to be in moisture content?
/Anna
