Concentration of water-soluble paint ingredients called “surfactants” on the surface of a latex paint. May be evident as tan, brown, or clear spots or areas, and can sometimes be glossy, soapy, oily, or sticky.
Latex paints contain surfactants designed to make applying them possible. All latex
paints may exhibit this tendency to some extent if applied in areas where moisture (rain, dew, bathrooms, laundry rooms, etc.) comes in contact with an uncured latex paint.
Cool temperatures will retard the paint’s curing process, which can allow surfactants to separate out and float to the top of the coating.
Moisture accumulating on a fresh latex paint will retard the paint’s drying. This moisture may extract and concentrate different water-soluble materials from within the paint onto the paint surface. When the water evaporates, a concentrated residue is left behind, causing staining, unsightly runs, and gloss patterns.
Inside: Wash the affected area with soap and water, and rinse. The discoloration may occur once or twice again before the surfactant is completely removed. When paint is applied in a bathroom, it should dry thoroughly before using the bath or shower. Remove as much staining as possible before repainting.
Outside: Apply paint to all surfaces during weather conditions that allow proper curing of the paint film. When surfactant leaching occurs, flush with clean water immediately, before the stains have sufficient time to set up or harden. Light scrubbing with a soft brush is acceptable. If stains cannot be removed in this manner, then repainting will be necessary during more favourable weather conditions.
In many minor cases, exterior surfactants will wash off with normal weathering.
All preparation and painting works should be in accordance to the AS/NZS 2311:2009 “Guide to the Painting of Buildings”.