Cemflow Grit Prime Primer to provide a key between non-absorbent existing floors and new underlayment (formerly known as Cemflow Don Grit Prime) You might also be interested in Cemflow GPU Self smoothing floor leveling underlayment Cemflow Base S Cement based self leveling industrial surface system Cemflow Primer Water based polymeric primer Cemflow TS350 Trowel applied cementitious screed