Woodchip wallpaper refers to a textured form of wallpaper that, while deft at hiding uneven or damaged walls, can give a room an industrial or less elegant atmosphere, particularly with the knobbly woodchips that protrude slightly from its surface. Removing such wallpaper is not only time-consuming, but can be an extremely difficult task to complete without damaging the walls behind. This doesn't mean you have to live with this kind of wallpaper; instead, by painting over such wallpaper you can adequately disguise it.
Combine 60 ml (1/4 cup) all-purpose household cleaner in a bucket with water. Dip a scrub brush in the mixture and scrub down the walls vigorously. Allow them to air dry.
Check the wallpaper for protruding nails, and hammer them down if you find any. Fill any cracks with caulk.
Pour any brand of cover-up plaster designed for textured wallpaper into a paint roller pan and dip a paint roller into it. Apply an even coat to one area of the wall, then smooth over the coat with the flat edge of a trowel. Repeat this process until you've covered the entire wall. Allow it to dry overnight.
Apply a coat of oil-based paint to the wall with a fresh paint roller. Work in even, uniform strokes until you cover the wall completely.