When painting the exterior of a home there may be problems with the paint that become evident. These problems usually occur innocently because of common mistakes that are made by the painter. However, exterior painting problems may lead to a great deal of work to repair the exterior paint – a job that can be avoided with a little knowledge.

Alligatoring of paint appears as the top coat of paint fails to adhere to the undercoating, leaving exterior paint that appears to have scales. This exterior paint problem occurs because the base coat is a latex primer and the top coat is an alkyd enamel. While the latex is a flexible paint, the alkyd enamel dries to a hard finish that will not adhere to the latex. To repair this exterior paint problem the paint should be sanded from the surface completely and latex enamel applied as the under and top coats to the exterior.

Blistering of exterior paint can occur when water or humidity affects the exterior paint surface. The exterior paint surface is affected by oil based paint being applied over a wet or damp surface. It can also be apparent if there is water leaking from an exterior wall, or the exterior painting job has been completed during times of high humidity. In each of these cases the affect is dominant because the exterior paint is oil based. To repair the exterior paint problem the surface should be sanded, and latex paint applied.

Chalking of exterior paint is evident when there appears to be a chalk-like film present after the exterior paint has dried. The exterior paint surface may also appear to be “running” with a chalk film on to other parts of the exterior of the house. The exterior paint problem is often caused because of the quality of the exterior paint, or because an interior paint was used on the exterior surface and the durability of the paint is not sufficient for outdoor wear.

To resolve the exterior paint issue of chalking, using a power washer to clean the surface of the powder chalk is recommended. Once there is a significant reduction of the chalking, allow the surface to dry and then apply a quality grade exterior paint over the finish. This will seal in the paint that has been applied and prevent further chalking on the surface.