As concrete moves through its initial drying period, regular checking of the moisture content can start after 30 days. In most cases it will take 60 days or more before the sub floor is dry enough for wood flooring installation to take place. Excess moisture in the concrete will cause problems such as condensation or failure of the adhesive under the flooring.
Moisture conditions in the concrete sub floor that ultimately create moisture problems in flooring are not the flooring contractors responsibility. All contractors should take a reading of the moisture content and let the customer know the reults before any flooring is laid. Unless the flooring contractor takes the initative to determine the potential problems, through testing for moisture content, he is the one who will get called by the customer because buckling has occured.
The flooring contractor can begin his determination with some subjective and logical questions, for example history of the building, age of the concrete, issues with surrounding buildings with damp and so on. The moisture specification of the conctete sub floor should be that the emmision of moisture vapor from the floor should not exceed 3 pounds per 1,000 square foot per 24 hours