What are the implications of painting over existing wallpaper?

Painting over existing wallpaper can lead to significant challenges, particularly concerning adhesive issues and the creation of uneven surfaces. When paint is applied over wallpaper, the moisture from the paint can react with the adhesive used on the wallpaper. This reaction can cause the adhesive to weaken, which may result in the wallpaper bubbling, peeling, or curling away from the wall. As the paint dries, any imperfections in the wallpaper—such as seams, texture, or damage—can also become more pronounced, resulting in an uneven appearance.

Furthermore, the existing wallpaper may not provide a suitable substrate for the paint, especially if the wallpaper has a glossy surface that makes paint adhesion difficult. Therefore, proper surface preparation is critical to avoid these potential pitfalls. This involves removing the wallpaper entirely or ensuring it is in good condition, securely adhered, and properly prepared before any painting takes place.