A water-based sealer is a surface preparation step to create a smooth transition for installing a wallpaper.
It is always recommended to apply water-based sealer prior to all wallpaper installation. It assist on creating a barrier against any incoming moisture penetration from the wall or leakage. Hence it stopped the growth of mould and fungus. It also create a stronger adhesive between the wallpaper and the base paint of the wall to ensure a longer lifespan of the wallpaper.