For installation of the parquet flooring on cement screed  moisture needs to be below 2 %,  and in the case of floor heating floors moisture in the screed must be below 1.5%.

Rough calculation regarding the drying of screed is that it dries 1 cm in a month,  and since the average screeds have a thickness  about  4.5 cm, drying time is about 5 months to reach moisture level below 2 %.

Small acceleration can be reached with a regular airing (windows open during the day half-open and during the night completely closed) or if you  lease equipment for moisture draining.  These equipment will not  dry only your floors, but also the walls, and will create a healthier environment with less humidity.