Dealing with Alkali Issues in Exterior Painting
Definition: Color loss and overall deterioration of paint film on fresh masonry.
CAUSES:
* Applying oil-based or vinyl water-based paints to new masonry that has not fully cured can cause painting poor alkali resistance.
PAINTING POOR ALKALI RESISTANCE SOLUTIONS:
* Allow fresh masonry surfaces to cure for at least 30 days before painting. If this is not possible, use a high-quality, alkali-resistant primer.
* Test alkalinity of the surface with phenolphthalein or a pH pencil.
* Paint with a high-quality water-based paint and avoid colors that are alkali-sensitive.
