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New Unpainted Masonry Surfaces
New concrete or plaster contains a high degree of moisture which is gradually lost as the surface hardens and dries. It is crucial that ample time is allowed for this drying out process. High moisture content is a common cause for premature paint failures, such as blistering and discoloration (moisture < 17%).
Concrete or plaster are also alkaline in nature and together with the presence of salts and moisture may cause paint systems to fail prematurely.
Masonry surfaces must be reasonably dry and free oil or grease and other contaminants before an appropriate sealer is applied
The sealer selected should be appropriate for the surface and the finish coat.
Previously Painted Surface
Surface and previous paint film must be sound and have good adhesion. If paint film is losing adhesion remove by hard scraping. High pressured water jetting (1500psi) must be carried out of the surface problem such as powdery, flaking, algae and fungus infestation and damp. Apply 1 coat of Dulux Fungicidal Wash to surfaces that are infected with algae and fungus. This will ensure algae spores are killed. Allow to dry before painting.
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