Any remaining adhesive residues must be checked to ensure that they are not water-softenable and that they are hard, sound and have enough cohesive strength to receive a levelling compound.
Where moisture-sensitive floorcoverings are to be installed the floor must be dry with less than 75% Relative Humidity (RH) when tested in accordance with BS 8203.
It's common for older properties built before the 1970s to not contain a structural damp proof membrane or to exhibit moisture readings up to 98% RH. In this instance, a pre-smoothing layer of ARDITEX NA followed by a suitable surface damp proof membrane such as ARDEX DPM 1 C is recommended.
ARDITEX NA can then be applied directly to the ARDEX DPM, up to 48 hours after application, to provide a surface ready to receive the floorcovering.