In most cases, it is not recommended to wallpaper over existing wallpaper, as the success depends on the type of paper already on the wall. While you might be able to cover non-coated wallpaper, you should never apply new wallpaper over a vinyl-coated one, which is more common. Doing so can lead to poor adhesion, resulting in bubbles, imperfections, and peeling. It can also trap moisture, potentially causing hazardous mold growth between the layers.

Even if the existing wallpaper is suitable, experts recommend applying only one new layer. Adding multiple layers (more than two total) can cause significant adhesion problems, leading to warping and bubbling. For the best results, the recommended approach is to remove the old wallpaper and all paste residue before hanging the new paper. If you are unsure about your wallpaper type, consider consulting a professional.

The average cost to install or hang wallpaper is around $575 per room or project, with typical prices ranging from $200 to $1,500. Costs can be higher for custom or luxury products. Since project size varies, it's often helpful to estimate labor costs per square foot, which generally fall between $1 and $7, with an average of $4 per square foot. The total cost depends on several factors, including the quality and type of wallpaper, the size and type of the room, and whether old wallpaper must be removed first. Opting for less expensive materials like peel-and-stick wallpaper or choosing to do the installation yourself can lower the overall cost. For the most accurate estimate, it is best to have a professional inspect the space and provide a quote.

While it is possible to paint over wallpaper, it is generally better to remove it first to guarantee a smooth, professional finish. Painting over wallpaper can save time, but it may lead to issues if not done correctly.

You can paint over existing wallpaper if it is in excellent condition: smooth, non-textured, clean, and firmly adhered to the wall. Ensure there are no bumps, tears, or peeling areas, and that all corners and seams are securely glued down. You might also consider painting over wallpaper if removing it would damage the underlying wall. Additionally, some wallpapers are specifically designed to be paintable, which can add texture to a room.

However, there are risks. If the wallpaper is textured, damaged, or peeling, these imperfections will show through the new paint. The moisture from the paint can also loosen the wallpaper's adhesive, causing it to bubble and potentially damage the wall. To mitigate these issues, clean the surface thoroughly and use an oil-based primer to help the paint adhere and prevent the old adhesive from bleeding through.

Wallpaper in bathrooms can last anywhere from one to 10 years, depending on what type was used, how well it was installed, and the measures in place to reduce moisture and humidity levels. Opting for a more durable variety and taking all the necessary protective measures will get you closer to that longer lifespan.