What Causes Paint to Crinkle?

Types of Paint

• Interior and exterior house paints come in several different formulations, some of which include latex, oil-based and acrylic. In general, paint materials hold their consistency while adhering to surfaces because of the ingredients used to make them. Paint, in and of itself, consists of a pigment, a binder and a solvent. The pigment gives the paint color. The binder acts as the adhesive that allows paint to stick to surfaces. The solvent makes it possible to spread or apply paint with brushes and rollers. All types of paint become filmlike as they cure. Some paints, such as oil-based, form a tough, plasticlike film, while latex paints dry to a less rigid surface coating.

Drying

• As all types of paint undergo a drying process, a crinkled effect develops on painted surfaces when undercoats failed to dry sufficiently. Not surprisingly, different types of paint dry at different rates. Oil-based paints never really stop drying. Instead, these paints are continually affected by oxygen exposure and, over time, become increasingly brittle. Latex-based paints dry quickly and retain a pliable surface texture over time. So, if paint is applied in multiple coats and the bottom coat doesn’t dry sufficiently, a wrinkled look can appear after additional coats of paint are applied. Paint color also affects the drying process, with darker-colored paints taking longer to dry.

Surface Conditions

• External conditions such as heat and humidity can affect how well paint adheres to a surface. Paint applied within hot or humid environment -- whether outside or inside -- may dry faster on the surface than on the bottom layer. When this happens, the paint develops crinkles in partially dried areas. Partial drying can also happen when applying paint in thick coats, with top surfaces drying the fastest. Primer-treated surfaces such as bare wood can also develop crinkles when the primer coat doesn’t dry completely. Walls or ceiling with dirty or waxy surfaces affect the paint drying process, causing wrinkles to form along moist or sticky areas.

Considerations

• For both interior and exterior applications, paint adheres best when applied on a smooth surface. Surfaces likely to absorb water will, in most cases, absorb paint. If paint absorbs in some areas and not others, this can result in uneven drying and eventual crinkling. Under these conditions, a primer coat is needed. In some cases, it’s possible to remove a crinkled area by scraping or sanding and then repainting in an even coat. A particular type of paint will also list the manufacturer’s specifications, so applying paint coats according to the manufacturer’s recommended spread rate can help reduce the likelihood of wrinkling.