| Cement Plaster Surface |
| Damp Surface | Dry Surface | Sheet-Float finish & Lime Plaster | Cement Rendered Surface | Textured finish |
Damp surfaces: Wet or damp surfaces should be handled with care as they are liable to chemical attack from alkalis. Oil paint applied to damp surfaces will not adhere and may blister or peel. Therefore initial decoration should be confined to emulsion paints which are porous and allow the breathing process to continue. Alkaline salts contained in the building fabric can be brought to the surface during the drying out process and then form a crystalline deposit, known as efflorescence. All surface deposits should be regularly removed by dry brushing and ideally paint should not be applied until all efflorescence stops.  Dry surfaces  Usually no complications are experienced when decorative paint systems are applied to dry surfaces. The general recommendation is to scrap off excess plaster, sand paper lightly and commence paint application. Steel-Float Finish and Lime Plaster:  Remove all efflorescence and loose material. Dust off. Fill small cracks and imperfections with Supafix Crack Filler, sandpaper down and dust off. Allow surface to become reasonably dry before applying emulsion paints. Surface must be completely dry before oil-paint is applied. Cement Rendered Surfaces. Fair-Faced & Pre-cast Concrete:  Remove dust, efflorescence and loose material with stiff brushes. Scrape off dry cement splashes. Large cracks and imperfections should be filled (by the main building contractor) with sand/cement mixture. On interior surfaces minor cracks in fair-faced and pre-cast surfaces can be filled with Supafix Crack Filler. Allow the surface to become reasonably dry before applying emulsion paint and completely dry before oil paints are applied. Textured Finish. Cement Bagwashed Surfaces: Brush down with stiff fibre brushes to remove any loose material and dust off. If surfaces are found to be patchy in appearance and porosity the application of a clear sealer should be considered if a uniform paint finish is to be obtained. |