Wallpaper Over Texture
Unfortunately, Installing wallpaper over texture is an issue in most modern homes. In order to keep from having to get the walls as smooth as they should be, builders have come up with all sorts of wonderful textures to cover a multitude of sin. Orange peel, knockdown, stucco and a host of others methods have spread like a disease in modern architecture. You would be hard pressed to find a home that is not infected. Thankfully, there are treatments for this malady.
do I need to smooth the wall
The best way to tell if your textured wall is going to have to be dealt with is to run your hand over it. If you can feel inconsistencies then they will probably show. Generally an orange peel texture is just fine, not further treatment is necessary. With a light sanding, you can go right on to priming.
what will happen if i just hang over it
Knockdown and other types heavier textures will however, require some further consideration. You have to ask yourself, do I want to see this texture through the wallpaper; if the answer is yes, then to what degree?
Letting it show … I have done many jobs in which the client did not want to lose the texture but wanted the paper anyway. In this case we went with very light weight, light colored material that would blend itself down into the texture of the wall. It looked awesome; the texture complimented the paper and visa versa. It was a very unique and novel look.
Picking a heavily textured material such as Grass Cloth or Mica wallpaper can positively effect this issue also. They minimize the effect the texture has on the wallpaper and look good with what little does show through.
WALLPAPER OVER TEXTURE
This illustration shows a typical pattern hung over textured walls
Bridging Material
This is very thick heavy wallpaper that is designed to bridge over gaps and inconsistencies in a wall. Typical material of this type really works best at covering minor damage, small cracks, and lighter textures on a large scale. There are however, specifically designed bridging materials that can tackle the big stuff. Using these products is not a cure for all texture problems. They do require that you do your best to knock down any nubs or dinks (scientific terminology) that will stick through. They require specific adhesives and installation processes that assure they will not come loose when you apply your finish paper. Finally, by the time they dry in, they usually eliminate about 85% of the texture.