Interior Painting Specifications
The performance of the paint or coating system depends not only on the quality of the paint, but also on the quality of the surface preparation. Even the highest quality paints that are applied to poorly prepared surfaces will fail to give the service expected.General surface preparation calls for all surfaces to be clean and dry. Remove all dirt, dust, rust, stains, scale, mildew, wax, grease, oil, bond-breakers, efflorescence, and other contaminants that can adversely affect the paint adhesion and performance. Completely remove all loose, peeling, or checked paint. In most cases, normal scraping, power sanding, hand sanding, or wire brushing will adequately remove peeling paint. A good paint and varnish remover may be used to remove old oil-base coatings. Use these removers in strict accordance with the manufacturer's directions.
Paint, regardless of quality, will peel if applied over old paint that is not adhering securely to the underlying surface. This happens because as the new paint film dries, it will contract and cause tension on the underlying coat(s) of paint, which could pull them loose.
Glossy surfaces should be dulled by sanding, washed with a solution of tri-sodium phosphate or treated with a liquid de-glossing compound, such as Paso, to provide a roughened surface, or "tooth", for good adhesion.
If mildew is present, remove it by washing the surface. Use a commercially available mildew remover, or use the following bleach solution, rinsing after with clean water:
- 1 gallon liquid chlorine bleach
- 3 gallons warm water
- 1/3 cup powdered detergent
- (2/3 cup Tri-Sodium Phosphate may be added for additional cleaning. However, this will leave a residue which requires a thorough, double rinsing).