If you have recently removed flooring laid on top of quarry tiles, it is quite likely you will find damp. This is not necessarily a serious rising damp issue. Instead, it is more likely, this is moisture trapped by the modern floor covering. Simply allowing the floor to breathe and dry out should remove this problem.
How do you clean quarry tiles before sealing?
Wash the floor with a cup of vinegar in a gallon of hot water, to remove all traces of grease, dirt and efflorescence, a white and powdery residue common on tiles. Allow the floor to dry. The desired result is a perfectly clean and dry floor.