Hanging wallpaper may seem simple, but in practice it requires significant planning and finesse to make it look professional. To start, you need to get an even application of wallpaper paste across all of your wallpaper, which requires experience and large pasting tables to get right. You also need to plan out your design and match it exactly so that you don’t have imperfections in the finished product. It’s often better to hire a professional wallpaper hanger who can get the job done properly for a clean, smooth finish.

Once again, contact with moisture is the culprit here, though water-resistant varieties of wallpaper are less likely to become wet and develop mold. Using a high-quality exhaust fan or dehumidifier and leaving the doors or windows cracked after bathing will keep this issue at bay. 

We don’t recommend wallpapering over older paper. That’s because creating layers of glue can invite bubbling or excess moisture on the wall’s surface. You should also prime your wall before applying wallpaper and smooth the wall as much as you can, and another layer of wallpaper complicates this process.

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.