Walls should be as smooth as possible before applying peel-and-stick wallpaper. Although you technically can apply wallpaper on textured walls, the peel-and-stick variety won’t last long without a clean, smooth surface for the adhesive to stick to. If you have textured walls, consult a pro about removing the textured finish before moving forward with wallpaper.

Yes, you can put wallpaper in a bathroom, but whether it's a good idea depends on several factors. Because bathrooms are high-humidity areas, it's crucial to choose a water-resistant wallpaper, such as one made of vinyl. Proper wall preparation is also critical to ensure the paper adheres well, even after many steamy showers. The wallpaper's placement also affects its longevity; it will hold up better on an accent wall or away from direct water contact, rather than immediately next to a shower. A well-ventilated bathroom will yield the best results.

Hiring a professional wallpaper hanger is usually a worthwhile idea because, while the application of wallpaper itself is easy, getting the finished product to look good is complicated and takes a lot of practice and patience. A professional wallpaper hanger will not only be able to hang your wallpaper seamlessly, but they will also get an even application of wallpaper paste to avoid bubbling and imperfections immediately and over time. Plus, they can provide their professional opinion on whether to remove or wallpaper over an existing layer of wallpaper.

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.