Causes

Powdery, chalky or friable substrate Moisture ingress Weakly adhering underlying coatings Inadequate surface preparation Adhesion failures resulting from surface contamination and inadequate surface preparation prior to treatment is a frequent cause of this type of breakdown. Moisture problems may occur in floor slabs that do not incorporate a damp proof membrane.

Solution:

Remove loose and failing material by scraping or brushing with a stiff bristle brush to a sound edge. Any oil, grease, polish etc must be removed with an emulsifying de-greaser. For surface dirt, wash with hot water and liquid detergent solution to remove any contaminants, frequently changing the water. Rinse thoroughly with clean water to remove all residues. Allow to dry. Feather edges of sound coatings and mechanically dry abrade any glossy surfaces to provide a key. Remove all dust by vacuum cleaning.