Why does paint fail?
Quality paint that’s been correctly applied can last for decades, but paint can also fail. Paint failure – when the paint cracks, peels, or bubbles – usually indicates a problem with the paint or its application. Let’s look at some of the most common causes of paint failure, and what you can do about it.
Common causes of paint failure
Poor surface preparation Surface preparation may be the single most important thing you can do to ensure the success of a painting project. Dirt, oil or grease, dust and other contaminants can prevent paint from bonding to a surface. Proper surface preparation starts with observation. If a surface is already painted, a thorough cleaning will remove any dust, dirt, or grease. If your intended target has cracks or chips in the paint, you’ll want to fill those with spackling paste. (Use wood filler for wood surfaces.) Once the repair has dried, sand it smooth and prime it before applying any paint. If your surface has never been painted before, you should clean and prime it before applying any paint.
Incompatible surfaces Paint can also fail if you apply it to a glossy, glazed, or milled surface. These surfaces don’t allow new paint to penetrate properly. Without anything to “stick” to, the paint will chip and peel readily.
Incompatible paints Not all paints make nice with each other. Water- and oil-based paints may or may not cooperate with each other, depending upon the order of application. For example, you can put latex paint over oil-based paint with good results, but oil-based paint over latex will fail. To get a good result with latex over oil, you must properly prepare the surface before painting. No amount of surface preparation (short of stripping) will produce a good result when you put oil over latex.
Exposure Exposure to the elements, including UV light, can deteriorate paint quickly. If you’re planning to paint an exterior surface, choose an exterior paint that can stand up to the elements. High quality exterior paints are UV- and moisture-resistant. They may also be designed for specific surfaces like wood or masonry.
Other causes of paint failure
Too much paint! Multiple layers of paint can cause problems. Covering up old paint doesn’t stop it from aging. As the oldest layers age, they lose their elasticity. This means they can’t expand and contract with temperature changes. The paint will take on an “alligator” look. (This usually happens on wood surfaces.) No amount of new paint will fix this problem. The only cure for an alligatored surface is removing the old paint completely before repainting.
Moisture and heat Moisture and heat can both cause paint failure. Painting a damp surface traps water between the surface and the paint. If the moisture can’t escape, it will create “bubbles” in the paint. Heat can also cause bubbling or blistering. Painting a hot surface can trap solvents in the paint. The outer layer of paint dries before the heated inner layer does. This causes a “blister” to form in the paint. Although moisture and heat failures look different, the result is the same: paint failure. A permeable surface can attract moisture from an unfinished side after you’ve painted it, too. Cinder block, often used for foundations, is a good example of a porous surface that can admit moisture. If you plan to paint a permeable surface, you may need to work with a special waterproofing paint.
Margo Painting and Power Washing offers professional painting services for residential and commercial customers. We take both interior and exterior painting projects and guarantee that you’ll be satisfied with our results! Please give Margo Painting and Power Washing a call at (330) 204-7277 for a cost estimate.