If the Parquet Will Be Laid on Top of the Concrete Base The Best Option Wuld Be to Use A Cement-Sand Mixture, And to Be More Precisely Organizing a Screen. If the is a desire, The You Can Apply A More Expensive Self -leveling Mixture. In the Event that Parquet Will Fit on a Wooden Base for Alignment You Can Moisture -Resistant Plywood and Wooden Lining.