All surfaces must be thoroughly cleaned and prepared. All loose particles, laitance, dust,curing compounds, floor hardeners, oil, grease,fat, bitumen and paint must be removed if good bond strength is to be achieved. Gloss surfaces must be abraded.If oil, grease, fat, etc. are present, they should bere moved before starting any other form of preparation. All laitance weak or friable concrete should be removed by chipping, grit blasting, or scrabbling until a sound base is obtained.All laitance should be removed by mechanical scarification, grit blasting, or by acid etching.Visible signs of mould growth, lichen, or algae,should be removed and treated with a fungicidal wash.New concrete should have cured until the shrinkage and moisture movement is low.Surfaces heavily impregnated with mould oil should be decreased and grit blasted or mechanically scarified to remove the contaminated surface. All curing compounds should have disintegrated or be removed and application carried out only onto a clean, dust free surface.