Paint burning is a loss of paint continuity on a stucco exterior.
Fresh stucco is highly alkaline, and its pH level ideally lowers to 10 as it cures. If stucco isn't properly hydrated, its pH level may be too high for painting. Paint burning occurs when the stucco is at pH levels higher than 10. At a high pH level, the stucco may react to rainfall and splashing with a short-term rise in pH, burning (attacking) the paint and breaking it down to reduce its sheen and color uniformity.
The breakdown of the paint coating allows further water entry and subsequent paint burning. The result is a loss of sheen and a mottled appearance on the home's exterior. Paint burning is particularly an issue in areas of the exterior where water tends to sit on the stucco, such as at eyebrow details. Paint burning can lead to aesthetic issues in the form of chips, holidays (small areas of missing paint), and large areas that have no paint coverage.
Cause 1:
Poorly hydrated stucco
If the stucco isn't properly hydrated, its pH level will be too high. At pH levels higher than 10, the stucco may react to rainfall and splashing with a short-term rise in pH, attacking the paint and breaking it down to reduce its sheen and color uniformity.
Cause 2:
Lack of primer coat
If primer isn't applied, alkalines in the stucco can more easily break down the paint coating.
Cause 3:
Inadequate first and second coats
If an inadequate topcoat is applied, the coating will be too thin overall. A thinner paint film enables alkalines in the stucco to more easily break down the paint coating.
Cause 4:
Inconsistent application
Inconsistent spraying and backrolling can create thin areas in the paint coating. A thinner paint film enables alkalines in the stucco to more easily break down the paint coating.
