When prepasted wallpaper is made, a thin layer of glue is applied to the back of the paper. This process takes place in the factory before the wallpaper is packaged for distribution and sale. The quality of the adhesive used varies from manufacturer to manufacturer and even from batch to batch.
The adhesive on the back of prepasted wallpaper must be activated before applying to the walls. This is generally done using water. A sponge saturated with water can be used or small pieces of the wallpaper can be soaked in a tray of water for several seconds. There are some alternatives to using water for activation. A special adhesive activator can be purchased that is made specifically for prepasted wallpaper. It is applied like paste and eliminates the need for water. There is also a product known as One Step Wallpaper Prep and Adhesive for prepasted wallpaper. Some hangers forgo the activation process and apply additional adhesive to prepasted wallpaper. This is not recommended because there could be a chemical reaction between the two adhesives, causing discoloration of the wallpaper or even repelling the paper from the wall rather than adhering it.
Once the prepasted wallpaper is activated, it must then be further prepared through a process called "booking." Booking keeps the paper moist and prevents the activated paste from dripping on the floor or other surfaces. The edges of the wallpaper are turned upward and laid on the middle of the paper. The resulting two halves are then pressed against one another without creasing the paper, similar to an accordion pattern. This fold should be held for approximately 10 minutes to allow the paper to "cure." Specific manufacturer instructions for booking will usually be included with the prepasted wallpaper.
The process for hanging prepasted wallpaper is almost identical to hanging traditional wallpaper. Once the paper has been activated and the booking process completed, the last step is to apply to the walls. Prepasted wallpaper should be applied with a wet sponge, smoothed with a smoothing brush or tool and properly aligned for maximum aesthetic appeal.