Apply over rough walls such as cinder block or paneling to provide a smooth surface for wallpaper.

Here is a real handy product for preparing wood paneling for wallpaper And for covering up a plaster wall that is too far gone to spackle or perhaps covered in a rough texture.

Liner paper is a smooth surface, heavy weight paper like product that is a real time saver. applied over wood paneling it will hide the grooves (some Mudding is necessary on real deep grooves), it also can be applied over textured walls prior to applying a smooth surface paper. it is available in several different weights from lite weight to very heavy. The width is normally 36" .

Along these lines another product,"embossed papers" is also a real time saver, These wallcoverings,also very heavy, come in a number of patterns from stucco like to the old tin ceiling look. They can be painted or finished in a Faux finish to simulate real tin or antiqued stucco.