To determine how many rolls of peel-and-stick wallpaper you need, measure the square footage of the walls you’re covering and divide that by the square footage that each roll covers. Add 10% to 20% of your total square footage to account for pattern matching or damage while installing.

It’s possible to hang your own wallpaper, but the process is tedious and potentially frustrating, and it can be challenging to get seams to line up and look clean and professional. Plus, depending on the type of wallpaper you’re installing, using too much or too little adhesive could cause damage to your drywall or plaster, peeling, and bubbling in the final product. It’s usually a better idea to hire a professional wallpaper installer to do the work for you, as the relatively low cost is justifiable, if only to avoid damage to your walls.

No, you don’t always have to remove old wallpaper before applying a new layer. However, you should pull off the existing wallpaper if it’s cracked, peeling, or in poor condition. We’d also recommend against putting wallpaper over textured or dark-colored wallpaper because the old layer may be visible through the new one. In addition, if you try to hang new wallpaper over vinyl-coated wallpaper, the adhesive might not stick properly. 

Ideally, you want to ask the wallpaper installers you’re considering for examples of past work, and references you can call. These will prove that the installer can handle your job, make your room look professional, and will also give you some insight into the kind of customer service you can expect. Before you start calling companies, you might want to narrow down your options by finding installers with mostly positive reviews online.