Can I Paint Over Swirled Walls With Semi-Gloss Paint on Them?

Considerations

• Whether you use a roller or an airless sprayer, you have to apply more paint to a highly textured surface than a flat one to get even coverage. A heavy coat of paint takes longer to dry than a thin one, increasing the likelihood of drips and sagging. This likelihood is more pronounced if the underlying surface has a semi-gloss coating. Not only can new paint separate before it dries on a semi-gloss surface, it can bubble or flake off afterwards, because a semi-gloss surface offers poor adhesion, especially if the room has moisture or the wall is dirty.

Cleaning and De-Glossing

• To get the best paint adhesion on any wall, it's important to clean and de-gloss it. The first step in cleaning is to scrape off any loose paint, but you need to do this carefully to avoid damaging the texture, so lightly scrubbing it with a scrub brush is preferable to using a scraper. Then you should wash the wall down with a solution of warm water and a strong detergent such as trisodium phosphate or a TSP substitute to remove grease. The detergent removes some of the gloss finish, but the surface will provide better adhesion if you then de-gloss the paint with a commercial de-glosser.

The Advantages of Priming

• While painters typically reserve primer for walls that haven't been painted, it can also be useful on painted walls, especially when lightening the color. The chemical composition of primer is different than regular paint; it adheres better to the surface and provides better bonding for paint that you apply over it. If you prime a textured wall before painting it, you'll get better coverage from the topcoat and won't have to apply as thick a coat, thus reducing the possibility of drips and other defects.

Applying the Topcoat

• The best way to paint a swirled texture is to spray it, but if that isn't practical, rolling is the next best alternative. Be sure to use a heavy-nap roller to ensure the paint gets into all the crevices created by the texture. Whether you spray or roll, avoid trying to get complete coverage with a single coat, or the paint will collect in the texture and sag or drip. Let each coat dry completely before you apply the next one. If you do have drips, repair them only after the paint has dried by sanding them lightly.