Screed moisture levels before laying laminate flooring

[Simon88]

We had our extension screeded at a depth of 50mm and were told we could lay laminate flooring after 5 weeks. It has now been 8 weeks since the screed was laid and our builder has been checking the moisture with a hygrometer over the last few weeks to ensure the moisture level is less than 12%.

The readings over the last few weeks have fluctuated around 12 to 14% and our builder says we should wait a couple more weeks before laying the floor. Out of interest we checked the moisture in the existing floor that was laid a few decades ago and we got readings between 12 and 14%.

This to me suggests we are good to go but I'd be keen to hear the opinions and experiences of others!

[B17NNS]

Dries at about 1mm per day. I’d say you’re good to go.

[Simon88]

Thanks. I think I'll go for it this weekend!

[Rodney Trotter]

The R/H ( relative humidity moisture level in the concrete) needs to be 75% or less.
Working for a flooring company, we would not take that risk without having a hygrometer on the floor for a week to check the R/H.
If you do go ahead use the underlay with polythene on that acts as Dpm and tape the joints so any moisture that comes out of the concrete does not attack the laminate in the future.
It will make the laminate expand and when the expansion gap has gone it will start to tent up,and then the fun really begins.